Archives of Academic Emergency Medicine. 2020; 8(1): e74 REV I EW ART I C L E The Potential Role of Super Spread Events in SARS-COV-2 Pandemic; a Narrative Review Anthony M. Kyriakopoulos1∗, Apostolis Papaefthymiou2,3, Nikolaos Georgilas4, Michael Doulberis3,5, Jannis Kountouras3 1. Department of Research and Development, Nasco AD Biotechnology Laboratory, Piraeus 18536, Greece. 2. Department of Gastroenterology, University Hospital of Larisa, Larisa 41110, Greece. 3. Department of Internal Medicine, Second Medical Clinic, Ippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, 54642 Macedonia, Greece. 4. Department of Nephrology, Agios Pavlos Hospital of Thessaloniki, Thessaloniki 55134, Macedonia, Greece. 5. Division of Gastroenterology and Hepatology, University Medical Department Kantonsspital Aarau, Aarau 5001, Switzerland. Received: August 2020; Accepted: August 2020; Published online: 21 September 2020 Abstract: Coronaviruses, members of Coronaviridae family, cause extensive epidemics of vast diseases like severe acute respiratory syndrome (SARS) and Coronavirus Disease-19 (COVID-19) in animals and humans. Super spread events (SSEs) potentiate early outbreak of the disease and its constant spread in later stages. Viral recombination events within species and across hosts lead to natural selection based on advanced infectivity and resistance. In this review, the importance of containment of SSEs was investigated with emphasis on stopping COVID-19 spread and its socio-economic consequences. A comprehensive search was conducted among literature avail- able in multiple electronic sources to find articles that addressed the "potential role of SSEs on severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) pandemic" and were published before 20th of August 2020. Overall, ninety-eight articles were found eligible and reviewed. Specific screening strategies within potential su- per spreading host groups can also help to efficiently manage severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) epidemics, in contrast to the partially effective general restriction measures. The effect of SSEs on previous SARS epidemics has been documented in detail. However, the respective potential impact of SSEs on SARS-COV-2 outbreak is composed and presented in the current review, thereby implying the warranted effort required for effective SSE preventive strategies, which may lead to overt global community health benefits. This is crucial for SARS-COV-2 pandemic containment as the vaccine(s) development process will take considerable time to safely establish its potential usefulness for future clinical usage. Keywords: Pandemics; epidemics; coronavirus; severe acute respiratory syndrome coronavirus 2; disease outbreaks; cost of illness; mass vaccination Cite this article as: Kyriakopoulos AM, Papaefthymiou A, Georgilas N, Doulberis M, Kountouras J. The Potential Role of Super Spread Events in SARS-COV-2 Pandemic; a Narrative Review. Arch Acad Emerg Med. 2020; 8(1): e74. 1. Introduction Severe acute respiratory syndrome (SARS) has periodically emerged as epidemics and its natural history could be uti- lized as a "compass" to comprehend and manage the cur- rent pandemic of SARS-COV-2. SARS-COV-2 the etiologic agent of the novel coronavirus disease 2019 (COVID-19), be- ∗Corresponding Author: Anthony M. Kyriakopoulos; Department of Research and Development, Nasco AD Biotechnology Laboratory, 11 Sachtouri Str, Pi- raeus 18536, Greece. Email: antkyriak@gmail.com, Fax : 00309210818032 longs to RNA coronavirus family (Coronaviridae) and is a zoonotic coronavirus that has crossed species barriers to in- fect human (1-3). The initially investigated strains of COVID- 19 exhibited low potential for transmissibility and infectiv- ity, similar to SARS coronavirus (SARS-COV ) (1-4). Moreover, SARS epidemic was potentiated due to super spread events (SSEs), which led to unexpected elevation of the basic re- production numbers as calculated via associated epidemiol- ogy equations (5). Specifically, SSEs resulted from secondary contacts of carriers (6, 7). Infected individuals, as mediators of SSEs, represent the initial cluster of viral transmission (8); thus, inducing an exponential secondary contamination (4). This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 2 Although the prediction and subsequently the prevention of SSEs seems to be complicated, the virus, host, environmen- tal, and mass behaviors determine relative approaches to prevent and control SSEs; core community health programs can inhibit and decrease the incidence and the effect of SSEs (9). Nevertheless, horizontal austerity measures, such as recom- mending or compelling individuals to self-isolate at home, which might cause serious social and psychological burden, and quarantine, also leading to loss of income due to so- cial distancing, are associated with negative psychological and religious effects, which can be long lasting (10), thereby leading to serious instability of the global society. Prolonged social isolation and loneliness are associated with increased mortality (11). Currently, limited piece of information exists regarding the effect of SSEs on coronavirus epidemics. The aim of this nar- rative review is to mainly focus on the potential impact of SSEs on large outbreaks of coronavirus. The development of an emergency SARS-COV-2 vaccine has its potential useful- ness and/or limitations and may result in severe health out- comes, which prompts better screening for SSEs in order to control coronavirus pandemics. 2. Method 2.1. Methodological approach To avoid, in most respects, literature selection bias (12), mul- tiple electronic sources: Medline/PubMed, SciFinder, Sci- ence Direct and Goggle Scholar as well as ResearchGate and General (Google) were investigated via queries with a non- restricted time frame reaching the 20th of August 2020. Ini- tial investigation of SSEs and SARS, SSEs and MERS, and SSEs and COVID-19, gave narrative results from PubMed. The selected literature, which is included in the study, is presented in table 1. Same items were also searched in all other mentioned sources. The scope of the study was not only to investigate the transmission of SARS-COV-2 due to SSEs, its comparison with SARS-COV-1 and MERS-COV, but also to assess the general global impact due to SSEs by COVID-19. Therefore, further literature investigation was performed using the same electronic sources. Further in- vestigation was made on: a) the prevention of SSEs by coronaviruses causing SAR-1, MERS and COVID-19, b) the socio-economic relation of SARS-COV-1, MERS and COVID- 19 due to SSEs, c) the austerity caused by SSEs of COVID- 19, and d) the relation of SSEs containment to future vac- cination programs. For further investigation, the follow- ing items were searched: "SARS, MERS and COVID-19 Epi- demic Prevention", "SARS MERS and COVID-19 Infectiv- ity and Pathogenicity", "Coronavirus SSE Prevention", SSE Coronavirus Crisis and Socio-economics", "Holy Cup Reli- gion and Transmission of Pathogens and SSEs", and "Coro- navirus Immunity and Vaccination". 2.2. Selection process Screening Process and Eligibility Criteria Studies providing an adequate determination of an SSE re- lated to SARS, MERS and COVID-19 were primarily screened and selected by two reviewers (authors) blinded to one an- other. The results were thereafter cross-matched and du- plicates were removed. Based on this primary search, the socio-economic impact of coronavirus, produced by SSEs, was extrapolated by two other reviewers (authors). Following this initial selection stage, further screening was performed by all reviewers, using the previously described search items to identify parameters determining the global impact of COVID-19 due to SSEs. Identified parameters included the global impact of immunity and vaccination, the holy cup and religion transmission, and the austerity caused by COVID-19 and other coronavirus epidemics due to restrictions applied. All search results were cross-matched to remove duplicates and thereafter, exclusion and inclusion criteria were applied. Exclusion and Inclusion Criteria After removing the duplicates, review was conducted on titles and abstracts. Also, a decision was made to remove "news press opinions". Computational model methodologies pro- ducing contradictory results, studies with wrong interpreta- tion of SSEs, and studies with non-clear-cut results were also removed. Studies using the interpretation "a super spread- ing individual, known as the index case, produces a cluster of SARS, MERS, and COVID-19 secondary infections" were included. A second exclusion criterion was applied. In this stage, peer reviewed literature of recent dates, studies as- sessing SARS, MERS, and COVID-19 epidemiology measures, studies on COVID-19 restriction measures producing social and economic austerity, articles discussing the perspective for future vaccination and population immunity, and finally genetic studies on coronaviruses causing SARS, MERS, and COVID-19. 3. Results By following the described methodology, on Med- line/PubMed: a) 23 articles were found on SARS and MERS and SSE, and b) 11 articles were found on COVID-19 and SSEs. Out of: a) 13 of the 23 articles on SARS and MERS and SSE, and b) 7 out of the 11 articles on COVID-19 and SSE were deemed relevant hits. After applying the exclusion criteria, 12 articles from the first category, and 4 from the second category were included in the study. Suitable articles found by searching, which were selected and reviewed for each part, are illustrated in figure 1. Further investigation in all other electronic sources described, using the same method- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2020; 8(1): e74 Table 1: Literature included from PubMed search for SSEs* in relation to coronavirus outbreaks Literature included in review for SARS∧ and MERS! in relation to SSEs* Authors and Year Type of article** Study description Chowell et al. (2015)(51) Comparative research Investigation of relation between SSEs for SARS and MERS trans- mission in nosocomial outbreaks Al Tawfig et al. (2020) (38) Commentary Demonstration of a stochastic model of transmission of SARS virus Shaw (2006) (55) Perspective review Implementing efficient intensive care practices to avoid hospital transmission Chen et al. (2006) (96) Original research Case control study Investigation of SSE likelihood during hospital transmission Sung et al. (2009) (97) Original research Case control study Investigation of SSEs occurring in hospital and prevention strate- gies Li et al. (2004) (54) Original research Case control study Investigation of factors contributing to SSEs for prevention and control of disease Riley (2003) (5) Original research Cross sectional study Analysis of SARS epidemiology in Hong Kong Stein (2011) (98) Perspective review Analysis of SARS transmission leading to SSE Gormely et al. (2017) (52) Original research Model for prevention of pathogen transmission via sanitary plump- ing systems Lau (2004) (53) Perspective review Implementation of SSE containment with vaccination programs Literature included in review for COVID-19 in relation to SSEs Cave (2020) (56) Perspective review Call for clear epidemiologic definition for SSEs Xu (2020) (57) Original research Retro- spective cohort study Analysis of SSEs during COVID-19 in China Kwok (2020) (58) Original research Analysis of SSE influence in the nature of COVID-19 epidemic Zhang (2020)(21) Original research Description of SSE importance in COVID-19 epidemic ! Severe Acute Respiratory Syndrome; ∧ Middle East Respiratory Syndrome; &Coronavirus Disease-19; *Super Spread Events; **When clearly indicated in article, the type of study is also mentioned. Table 2: The search results of literature related to COVID-19& global impact due to SSEs* Search Item Medline/PubMed Other electronic sources** Number of arti- cles retrieved Number of arti- cles included SARS!, MERS∧, and COVID-19 epidemic prevention 42 3589 139 17 SARS, MERS, and COVID-19 infectivity and pathogenicity 672 3812 145 18 Coronavirus SSE prevention 10 627 151 22 SSE, coronavirus crisis, and socio-economics 4 3181 89 11 Holy Cup religion and transmission of pathogens and SSEs 0 15 4 4 Coronavirus immunity and vaccination 73 20975 1175 9 &Coronavirus Disease-19; *Super Spread Events; ** Science Direct, SciFinder, and Google Scholar; !Severe Acute Respiratory Syndrome; ∧Middle East Respiratory Syndrome ology, increased the number of the included literature to a) 17 and b) 14, for their respective categories of search. Studies included from PubMed in these categories of searches are briefly described and listed in table 1. Further, assessing the general global impact of SSEs related to COVID-19, using all the mentioned sources, via the same methodology, led to the inclusion of a) 10 articles related to genetic analysis of SARS- COV-1 and MERS-COV and SARS-COV-2, b) 5 articles related to super spread events, c) 2 articles related to austerity, d) 18 articles related to infectivity and pathogenicity of SARS, MERS and COVID-19, e) 17 articles related to prevention of SSEs concerning human coronaviruses, f ) 9 articles related to socio-economic impact, and g) 9 articles related to im- munity and future vaccination. Table 2 illustrates the initial numbers of hits using all search items in all sources, and the final number of articles reviewed in each category. 4. Discussion 4.1. Insights to SSEs The involvement of SSEs in SARS extensive outbreaks (1, 4, 5, 13-17), necessitates urgent elucidation as global tranquility is This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 4 Figure 1: Method followed for PubMed search and literature selection regarding SSE in relation to a) SARS-1, MERS and b) COVID-19 out- breaks. disturbed by COVID-19 pandemic. Epidemiological research has proposed that the outbreak was related to a seafood mar- ket in Wuhan (Hubei, China), underlining the ongoing risk of viral transmission from animals to induce severe diseases in humans. Metagenomic RNA sequencing of bronchoalve- olar lavage fluid from a patient with pneumonia identified a novel RNA virus strain from the Coronaviridae family (called SARS-COV-2); and phylogenetic analysis (by introducing the widely used in silico protein screening) (18-21) of the com- plete viral genome (29,903 nucleotides) disclosed that the virus was most closely connected (89.1% nucleotide similar- ity) with a group of SARS-like coronaviruses (genus Betacoro- navirus, subgenus Sarbecovirus) formerly isolated from bats in China (18-22). Insights from previous reports by Menach- ery et al. (23) (Menachery et al., 2015), pointed out that the 2002-2003 emergence of SARS-CoV introduced the possibil- ity of viruses of animal origin causing epidemics in human populations. Conclusions from their study revealed, as pre- vious studies had demonstrated (1, 5, 13, 15), that closely related SARS-like viral genes were traceable in Chinese bat populations. Authors claimed that these viruses were capa- ble of infecting humans, by selective adaptations or adjust- ments, and thereby, causing a new epidemic (23). Enhance- ment of virulence is also attributed to these adaptations due to acquisition of spike protein via adaptive mutations (24). Continuous viral random mutations are possible through in- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 5 Archives of Academic Emergency Medicine. 2020; 8(1): e74 Figure 2: Flow of genetic variation of coronaviruses leading to increase of virulence and pathogenicity; epidemiologic steps for specific and targeted diagnosis to prevent super spread events. Blue arrows point to the flow of genetic variation across gene pools where genetic variation occurs, i.e. a) between hosts of the same species, b) between hosts of different species by crossing the species barrier, spreading to c) humans and subsequently to super spreader individuals, where disease transmission is potentiated. Grey arrows point to specific identifications that can lead to effective interventions with the potential to control the disease spread. termediate host transmission, until a deadly virus develops, as illustrated in Figure 2. Recent evidence revealed that re- combination within intermediate hosts has contributed to development of SARS-COV-2 (1, 24). Asian outdoor markets could constitute the ideal places for continuous viral muta- tion exchanges (25). As presented in Table 3, the best way to circumvent continuous virus production is targeted surveil- lance; to at least stop the overspreading by SSEs (2, 3, 22, 26). This has also been proposed by Menachery et al. (23). 4.2. SARS epidemics and SARS-COV-2 pandemic SARS-COV-2 is accountable for the unprecedented COVID- 19 pandemic (27), and the interplaying mechanisms involved in the pathophysiology of COVID-19 include SARS-COV-2 virulence, host immune response, and complex inflamma- tory reactions (28). Emerging data, also, imply that the reser- voirs of SARS-COV-1 infection may be similar to COVID-19 (1, 4, 5, 13, 29), as remarkable similarities exist between SARS and swine acute diarrhea syndrome (SADS) in topographi- cal, temporal, environmental and etiological backgrounds. However, the increasing coronavirus variety and spread in bats were recognized as a potential target to diminish future epidemics that might impend livestock, community health, and financial progress (30). Probably, identification of an- imal and insect vectors that transmit the disease, identifi- cation and control of alternative routes of transmission like fecal-oral route, and identification of super spreader patient groups could help minimize the epidemiological extent com- pared to the one observed for SARS-COV-2 infection world- wide. Lessons from SARS epidemic taught us that the key to control is minimizing the time from the diagnosis of infection to prompt hospital isolation and diminishing the probability This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 6 Table 3: Key clinical and laboratory screening functions to appropriately forecast, prevent, and confront SARS! Coronavirus 2, and future coronavirus epidemic waves Specific Clinical and Laboratory Investigation Validated techniques to be used Forecasting of pre-symptomatic infection To estimate the probability of a major outbreak, use simulations of stochastic compartmental epidemic models. Use of diagnostic tests to detect asymptomatic susceptibility and pre-symptomatic infectivity Estimation of Super Spread Events of current and previous coron- avirus epidemics Introduction of individual reproductive number. Integrated and computational analysis of the influence of individual variation by binomial distribution and use of branching process analysis of dis- ease data. Genetic characterization of inpatient viral isolates to identify in- termediate animal hosts facilitating the infection Next generation sequencing of samples and cultured viral isolates to obtain full sequence and phylogenetic analysis application. Environmental detection and continuous sewage monitoring RT-qPCR# screening on sewage systems, vectorsÙĹ and potential air transmission. Autopsies and detection of serology conversion of potential vectors. Heptad repeat region screening for positive selection Computer simulation models to detect positive selection events e.g. codeml branch-site Test coupled with Bayes empirical Bayes procedure, and mixed effects model of evolution. Receptor recognition analysis of ACE-II+ to identify origin of cross- species and human to human transmissions coronaviruses Genetic sequencing and phylogenetic analysis of ACE-II to provide origin and efficiency of cross-species and human to human trans- mission and identification of intermediate hosts. !Severe Acute Respiratory Syndrome; #Reverse Transcriptase Quantitative Polymerase Chain reaction; +Angiotensin-converting enzyme-II. Table 4: Potential groups of coronavirus super spreaders within the human population* Population Group Potential route of transmission Hepatitis B and C virus positive patients Airborne Pulmonary tuberculosis positive patients Airborne HIV! positive patients Airborne, urine & fecal-oral (98) Patients receiving hemodialysis Airborne (droplets by nebulizer) and fecal-oral MRSA# Staphylococcus aureus acquisition Constant Worn Glove Contact Transmission Rhinovirus co-infections Airborne Gastrointestinal (Salmonella enteritis) co-infections Fecal – oral Frequent contact with wild animal reservoirs (including domestic animals) and birds** Airborne and fecal – oral Construction area workers Air particles Sewage system workers*** Fecal – oral *In both community and hospital environments. **Including slaughter houses, pet shops, animal and bird collectors and breeders, cow, and pig farmers. ***Including workers coming in contact with environment contamination. !Human Immunodeficiency Virus, #Methicillin Resistant Staphylococcus aureus. of another SSE (5). 4.3. The 20/80 rule as applied to SARS The typically recognized 20–80 rule or the so-called "Pareto rule", states that 20% of efforts lead to 80% of results (31). More specifically, this comprises a principally convenient state when tackling infectious diseases and is applied to in- vestigate infection transmission, and initially among cattle farms. In this regard, Woolhouse et al. (17) reported that tar- geted actions concerning disease control and prevention in 20% of the farms that mainly supplied the basic reproduc- tion number (Ro) decreased spread by 80% (32). Focusing on the COVID-19 virus, Ro is a sign of virus transmissibility, denoting the average figure of novel infections caused by an infectious individual in a totally naive population. For R0 > 1, the number of infected people tends to increase, whereas for R0 < 1, transmission is likely to stop; Ro represents a chief model in the epidemics, signifying the risk of an infec- tious mediator with regard to epidemic spread (33). Recent data indicate that the estimated mean Ro for COVID-19 is al- most 3.28, with a median of 2.79 and the interquartile range (IQR) of 1.16, which is substantially higher than WHO’s es- timation of 1.95. However, due to biased methodology, Ro for COVID-19 is expected to be about 2–3, which is approxi- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 7 Archives of Academic Emergency Medicine. 2020; 8(1): e74 mately consistent with the WHO estimate (33). SSEs appear to be a main limitation of the Ro concept. Ro, when calcu- lated as a mean or median value, does not include the het- erogeneity of transmission between infected individuals (4); two infective agents with equal R0 estimates might have no- ticeably diverse patterns of transmission. Moreover, the goal of a Health Care System is to achieve Ro <1, which is prob- ably only phenomenally feasible in certain conditions with- out scheduled prevention, recognition, and response to SSEs (9). Naturally, epidemics follow the aforementioned 20 / 80 rule (17). Specifically, in human population, due to heteroge- neous exposure to infectious agent, the 20% core population may transmit the disease, widely. For SARS, the rate might have been even lower than 20% (4). The increased infec- tious potential of a small population subgroup seems to be related to immunodeficiency, such as in hemodialysis, can- cer, immunosuppressive therapies (4, 5, 15, 34). Additionally, facilitation of disease spread and transmission due to vec- tor exposure has been investigated in relation to cockroaches (35). Possible mechanical transportation by rats and cat (13, 36) and air transmission (37) in SARS-COV-1 have also been studied. Other animals capable of being SARS-COV-2 carri- ers (excluding mice and rats), like pigs, ferrets, cats, and non- human primates have recently been introduced (3), and con- tamination of sewage with SARS-COV-2, has probably pre- ceded COVID-19 outbreak in France (29). All these agents may contribute to a minimum of 80% of the total transmis- sion potential (17), maybe even more (4, 5). Table 4 displays possible super spreader groups; thus, indicating screening targets to prevent SSEs. SARS epidemic taught us that control programs were inefficient in controlling the epidemic within a population, and failed to identify and provide a targeted infection diagnosis in groups causing potential SSEs (5, 17). On the other hand, SARS-COV-2 having the ability to cause a pandemic rather than an epidemic, resulted in an increased number of cases and deaths; albeit having a lower mortal- ity rate than SARS coronavirus (2). SSEs during COVID-19 may involve not only one city, but also a whole country or many countries, requiring investigation of their effects on a national or international level (2, 38, 39). 4.4. Prevention of SSEs Preventing and decreasing COVID-19-related SSEs necessi- tates the decryption of the mechanism through which SARS- COV-2 spreads through super spreader individuals, for exam- ple within healthcare facilities (7, 9). Healthcare facilities are essential for prevention and control of SSEs (9). SSE preven- tion may enable us to even overcome initial low COVID-19 virus infectiveness. The capability of the virus to produce SSEs troubles the epidemiological attempts to restrict viral spread only by isolating individuals at high risk and perform- ing obsolete isolation at home for the general population as carried out in countries such as Greece (5). During the SARS epidemic in China (Beijing) and Singapore, the vast major- ity of infected individuals were barely infective and only 6% of the population was highly infectious, in contrast to many published SARS models (4, 5). Other ways of potential coro- navirus transmission between hosts may provide explana- tions for enormous outbreaks (16). It should not be disre- garded that coronaviruses cause both respiratory and intesti- nal infections and share common evolutionary roots with hepatitis viruses (40, 41). Passing the cross-species barrier and genetic adaptation within hosts may promote virulence of coronaviruses in humans (14). This, prompts to specifi- cally identify potential super spreader groups within popula- tions through targeted diagnosis. Some of these groups are listed in Table 2. For this purpose, a usual infection must be distinguished from a super spread infection (4, 5). Dur- ing SARS epidemic, the coronavirus infectiousness mostly occurred in the late stages of infection (5, 17), whereas in COVID-19, viruses are transmitted even in pre-symptomatic stages (42). As with Influenza A virus subtype H1N1 trans- mission (43), accurate diagnosis of COVID-19 in potentially asymptomatic super spreaders may help contain the magni- tude of large outbreaks (44). In the case of Diamond Princess Cruise ship, an early- assessed R0 of 14.8 (âL’́L4 times higher than the R0 in the epi- center of the outbreak in Wuhan, China) was decreased to an assessed effective Ro of 1.78 following on-board isolation and quarantine processes (45). Similarly, in China (Wuhan) the application of non-pharmaceutical interventions in the so- ciety, including a cordon sanitaire of the town; interruption of community transport, school, and most employment; and termination of all community events decreased the Ro from 3.86 to 0.32 over a 5-week period (46). Nevertheless, these strategies could not be maintained. Emerging research evidence (29) regarding sewage contam- ination that preceded Paris COVID-19 epidemic is pointing to the reports of 2003 from the health department of Hong Kong (35, 36), the noble work by Ng (13), and urge for ex- tensive environmental monitoring (29, 37) to prevent future COVID-19 relapses. However, the flow of genetic variation may be even more complex as illustrated in Figure 2. There- fore, advanced clinical and laboratory monitoring is required to prevent SSEs and thereafter, new coronavirus epidemics. Assembly of key functions and screening techniques of ref- erence centers is presented in Table 3. Newer therapeu- tic agents and protocol applications are promising (47), al- though probably carrying the possibility of resistance state (48). First, these also require specific diagnostic and surveil- lance strategies to overcome any unknown adverse epidemi- ology consequences (48). Inhibiting wild meat markets and related consumption of wild meat by creating vivid cam- paigns could be a critical for interrupting the introduction of This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 8 coronaviruses crossing from animals to the human popula- tion, as was the case for SARS (1, 4, 5) and Middle East respi- ratory syndrome (MERS) (49) epidemics, and probably now for COVID-19 pandemic (1-3). Furthermore, the food pro- duction process requires radical reconsideration, concerning the industrial environment of current food production and serious violations of natural ecosystems (50). Current indus- trial procedures for preparing food increasingly favor condi- tions where viral evolution produces new mutations and in- creased rates of mutations (25), thus raising the probability of new and more infectious viral strains. In SARS and MERS epidemics, the role of SSEs in vigorously distributing the epidemics has been substantially proven (51-55). The new COVID-19 epidemiology evidence also adequately highlights the important role of SSEs in homeland of China (21, 56, 57), although surprising evidence from neighboring coun- tries show the unlikely role of SSE in the spread of the disease (58). 4.5. Effective molecular screening of SARS-COV-2 and socioeconomic relations The Coronaviridae family is characterized by a positive-sense single-stranded RNA genome. Mouse hepatitis virus is a rep- resentative member of the family (41). Additionally, human hepatitis E virus also has a positive-sense single stranded RNA genome and shares a common evolution pathway with coronaviruses (40). Hepatitis-related incidents were de- scribed for SARS (59). The genetic recombination of these viruses within arbitrary intermediate hosts produced conta- gious strains that are extremely pathogenic to humans (40, 60). In this respect, the relation of SARS-COV genetic se- quences isolated from human, civets, and bats permitted us to find the reason for such a dangerous epidemic, which af- fected people on a worldwide scale in 2003 (61). Moreover, the unpredictable epidemic of MERS-COV posed a serious risk to the health of communities worldwide. These under- scored the necessity for further research of the virus epidemi- ology and pathophysiology to develop successful therapeu- tic and preventive medications against MERS-COV infection (62). While SARS-COV-2 is genetically and structurally con- nected with MERS-COV, it has its own exclusive structures which are responsible for its quick spread throughout the world (60). Specifically, variations in coronavirus pathogenicity within different species (63) make the understanding of SARS epi- demics even more unclear through their capability to over- come the barrier for cross species transmission, which also alters their infectivity status (14, 64). As a result, boosting the pathogenic behavior of coronavirus strains, within species (65), and across species barriers (49), which is a reflection of their positive adaptation to rapid recombination events (49). The recent MERS epidemic revealed the tendency of the strain to genetically adapt and produce greater outbreaks (49) as occurred in SARS epidemic in 2003 (66). However, mainly for socioeconomic reasons, alarm signals were ig- nored until recently (67). A new phylogenetic analysis tech- nique employed on clustered COVID-19 strains displayed a geographic variation preference in infectivity and pathogen- esis (39). This is probably due to predominating strain’s ten- dency to cause an SSE as an outcome of a multi- factorial epi- demic process presented in Figure 2 (23, 24). Marked SSEs for COVID-19 have already been fully characterized and warrant urgent investigation (23, 24). As presented in Tables 3 and 4, each way of transmission should be investigated. Hetero- geneity of epidemic characteristics across nations (39) im- plies that in this way we may minimize coronavirus trans- mission. Therefore, salvation of national economic catastro- phes will also be achieved in this way (66). Thus, the whole Biomedical Science machinery needs to perform targeted di- agnosis of SSEs and share the obtained experience. Sub- sequently, central authorities will no longer need excessive non-specific contact measures, which will in turn normalize both societal and economic activities. 4.6. SSE-related large outbreaks and uncon- trolled austerity On the other hand, improper understanding of how COVID- 19 spreads resulted in societal imbalance due to arbitrary re- striction of social and religious life including Holy Commu- nion Cup. It has been consecutively demonstrated by ex- pert research that the Holy Cup (Chalice) and the Holy Cloth are not sources or pathways, for potential spreading of in- fectious diseases including Human Immunodeficiency virus (HIV ) (68), Hepatitis B virus (HBV ) (69) as well as other com- municable pathogens (70). Specifically, a review (69), con- sidered other 129 relative studies. In this review, the possi- bilities that the shared communion cup can act as a vehicle for indirect transmission of human immunodeficiency virus, since it was detected in the saliva of infected individuals, was investigated. It was emphasized that although for bacterial contamination, the alcoholic content of the wine, the mate- rial that the cup is made of, or the practice of partially ro- tating the cup, cannot stop the occasional transmission of microbes, the microbial transmission was considerably re- duced by the intervening use of a cloth to swab the lip of the cup between communicants. Notably, it was emphasized that transmission means not an obligatory inoculation or in- fection. Furthermore, it was also emphasized that out of the epidemiology of microbes transmitted via saliva, particularly for the transmission of the herpes viruses, the indirect trans- mission is rare, and indeed transmission is highly possible by other means than by the saliva. It was also emphasized that neither hepatitis B virus nor human immunodeficiency virus infection can be transmitted by saliva, rendering their indi- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 9 Archives of Academic Emergency Medicine. 2020; 8(1): e74 rect transmission also less likely by inorganic objects. Finally, the study concluded that no episode of disease transmission has ever been reported as a result of the shared communion cup use, and that there was not any scientific evidence that the communion cup practice should be abandoned due to the possible risk of spreading of any infection (71, 72). Like- wise, Kingston et al. (68), by considering 44 relative papers, also concluded that there is no evidence that the Holy Com- munion Cup spreads infections. Moreover, more recent esti- mations also demonstrated that no infections have ever been observed as a result of religious rituals including Christian Common Communion chalice practice (70); whereas, data of previous studies implied that saliva could play a role in HBV transmission, are likely to be trivial (69). Similarly, recent ev- idence indicate that, although HBV DNA and HCV RNA can be discovered in the saliva of infected patients, they seem un- likely to transmit infection (72). It should be noted that, as in the case of coronavirus (73, 74), HBV also exists in many body fluids including saliva, nasopharyngeal fluid or tears by mea- sures of qualitative and PCR methods (75). The detection of HBV DNA in saliva motivated our study group to investigate the potential viral transmission through the Holy Communion Cup. Two successive retrospective studies were conducted to investigate the role of Holy Com- munion as an independent risk factor of HBV dispersion. The first preliminary study included patients from our reg- istry of those with chronic hepatitis B under entecavir ( Jannis Kountouras-personal communication) treatment (76), and in the next step, the relative registry of another Depart- ment of the same Hospital was incorporated. Other param- eters studied, the substantial independent categorical vari- able to evaluate our hypothesis was the patients’ occupation, thereby introducing two sub-groups; priests and non-priests. This classification was performed based on a standard active and perpetual exhibition (at least once weekly) of priests to many people’s saliva, as a part of the grounded process of the Holy Communion Cup. The control group comprised of the aggregate of Orthodox priests in Greece (10,338) and the rest general population (10,680,866) at that timeframe. Ap- proval of the Institutional Ethics Committee was obtained and all predispositions of the Helsinki Declaration were ful- filled. The reservoir database did not include any personified information (name, ID number, etc.) and thus no informed consent was required. Pearson’s chi-squared test with 1 de- gree of freedom was performed to evaluate whether there was a statistically significant difference between the frequen- cies of HBV infection in case and control groups and statisti- cal significance was set at p <0.05. The first single-centre registry included 71 patients and one (1.4%) of them was a priest. Chronic hepatitis B was signifi- cantly more frequent among non-priests compared to priests (x2 (1, N=71)=12.65, p <0.05). The extended sample (N=429) included the registry of another Department and an aggre- gate of four (0.93%) priests were diagnosed with chronic hep- atitis B. Likewise, the chi-square test revealed that non-priest subjects were more likely to suffer from chronic hepatitis from HBV infection compared to priests (x2 (1, N=429) = 31, p <0.001). In conclusion, both of our analyses indicated a lower prevalence of HBV chronic hepatitis among priests when compared to other occupations. 4.7. Coronavirus vaccination and relationship with SSEs Currently, vaccines for COVID-19 are in pre-clinical devel- opment, and no final clinical phase has been ended due the recent emergence of the disorder. Many global enti- ties have stated their plans to produce a vaccine for COVID- 19. According to the WHO, 41 candidate vaccines are be- ing produced for COVID-19 as of March 13, 2020 (77). Im- portantly, for production of highly effective and safe COVID- 19 vaccines, features such as the possibility of the induction of antigen-dependent enhancement (ADE) and additional severe opposing effects previously detected with SARS and MERS should be considered. ADE is a phenomenon that oc- curs when non-neutralizing antibodies against proteins of a virus increase, also increasing virus infectivity (78). In this regard, coronaviruses can escape the immunity provided by inactivated or recombinant protein vaccines via fast evolu- tion (79). The problem with live attenuated vaccines is that the coronavirus can recover its virulence via serial passages in cell culture or in vivo (80). Moreover, vaccination in an- imals and humans could facilitate, rather than inhibit, the pathogenesis of the targeted viruses. This can be the con- sequence of an ADE phenomenon. This underlines a mech- anism by which specific antibodies facilitate infection with the targeted virus, or cell-based augmentation, a process re- sulting in an allergic inflammatory response induced by im- munopathology (81, 82). Many experimental SARS-CoV-1 vaccines have been formu- lated from whole inactivated viruses, due to their advan- tage of large-scale production, multiple epitope presentation and high conformation stability (83). One such vaccine uses viruses from AY71A217 strain of SARS-CoV-1, which are dou- ble inactivated using formalin and UV irradiation, the so- called double-inactivated virus (DIV ) vaccine (84). Although DIV had initially been demonstrated to induce neutralizing antibodies and to protect against SARS-CoV-1 viral replica- tion, both in tissue culture and in young mice, it soon became apparent that older mice suffered from vaccine-induced im- mune pathologies, including failure to contain viral replica- tion, augmented clinical disease and associated symptoms, and increased inflammatory response and eosinophilic in- flux (84, 85). In this respect, there is an overlap between the immunopathologic responses connected with coronavirus This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 10 disease and vaccination, and the role of T helper (Th) 17 cells in immune augmentation and eosinophilic lung im- munopathology; host Th17 polarized inflammatory reac- tions portray an important role in the pathophysiology of COVID-19 pneumonia and edema (86, 87). Eosinophilic pathology, indicating increased pathogenesis and disease severity in the elderly, has been attributed to the nucleocap- sid (N) protein, despite the incorporation of multiple SARS- CoV-1 antigens in the DIV (82, 84). This is on grounds that the N protein is a strong modulator of innate immunity, also acting as an interferon antagonist, and therefore, it has the capability to induce inflammation with subsequent immune pathology in situations of heterologous viral challenge or in immune senescence, where patients fail to mount effective immune responses against the disease (84, 88). The route of transmission is important to be established for SARS COV- 2. As seen with other important infectious diseases of a) air borne transmission such as tuberculosis (89), b) orofe- cal transmission such as HEV (90) and c) blood transmis- sion such as HBV and hepatitis D virus (91), even if effi- cient vaccination is established, understanding of SSEs is still important. Recent research data on the immune re- ceptors used by coronaviruses, which reflect their ability to propagate in the human population, imply that complex im- mune reactions are responsible for a cell to cell transmis- sion. In addition to ACE-II receptor, as is the case with SARS- COV, MERS-COV (92) and possibly for SARS-COV-2 (92, 93), viruses use complex receptor recognition systems common to immunopathology damage mechanisms in coronavirus- infected individuals, which clearly define the clinical out- come (94). Therefore, application of vaccines that may inter- fere with antibody-mediated infection by coronaviruses (95) without true epidemiologic containment of coronaviruses, to restrict genetic adaptation events and inevitably producing an SSE, may be a miscellaneous attempt. However, synergy of SSE prevention measures with proper vaccination can pro- vide a robust attempt for disease containment. 5. Limitations This study aimed to perform a literature review. Although effort was made to decrease the risk of bias of results via double-blind screening of literature and employment of mul- tiple electronic search engines, bias cannot be eliminated due to incomplete retrieval of identified research and biased estimations of included literature conclusions and methods used. Outcome of the study may also contain biased estima- tions originating from wrong interpretation of super spread- ing individuals in literature reviewed for SARS, MERS, and COVID-19 outbreaks. Although the importance of SSEs in COVID-19 was recognized by this study, more data from fu- ture accumulated epidemiology studies are needed to justify these findings. 6. Conclusion Taken all together, management of SSEs is mandatory to yield efficient control over SARS-CoV-2. This is achievable through early diagnosis of pre/asymptomatic infected indi- viduals within potential super spreading groups. Prevention of outbreaks is more essential, especially due to the lack of efficient vaccination and therapeutic protocols, which ne- cessitates efficient monitoring, as SARS-COV-2 virus follows complex infectious patterns. The SARS-COV-2 epidemiolog- ical models that do not take SSEs into consideration seem to lead to confusing results with high uncertainty. SARS-CoV- 2 causes prolonged "pandemics" through complex adapta- tion routes. Currently, in addition to the high technology uti- lized for diagnosis, clinical observation is indispensable to deeply comprehend SSEs and prohibit further outspread of COVID-19. Reference laboratories with efficient and accred- ited molecular and serological diagnosis must be inter-linked between countries. All these parameters could contribute to avoiding a second blind unjustified response that character- ized the first COVID-19 pandemic spread. Understanding the epidemiology of COVID-19 through SSEs could be preventive for future epidemics. A systematic meta-analysis research methodology, when COVID-19 epidemiology data accumu- late further, would be advisable to confirm the conclusions of this study. 7. Declarations 7.1. Ethics approval and consent to participate This study did not involve the participation of any humans or animals as it was based only on literature research. 7.2. Consent for publication All authors agree to publish this manuscript. 7.3. Availability of data and materials All data used for this manuscript are available upon request 7.4. Competing interests All authors declare that they have no competing interests. 7.5. Funding No funding or grant was received for this study. 7.6. Acknowledgements We thank our families for providing moral assistance to ac- complish this study. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 11 Archives of Academic Emergency Medicine. 2020; 8(1): e74 7.7. Author contribution AK inspired the conception and drafted the initial manuscript. JK revised substantially the manuscript, in- tellectual content and provided disclosed data for HBV investigation. AK and JK made the primary double-blind search. AP, JK, AK, MN, and NG, made all other searches. AP contributed to the immunology aspect of manuscript. AP and NG aided in the clinical part and preparing the final version of the manuscript. MD contributed to biblio- graphical search and revision of the manuscript. All authors contributed to the English editing of the manuscript. âĂČ 7.8. Abbreviations SARS: Severe acute respiratory syndrome. SARS-COV-2: Severe acute respiratory syndrome coronavirus -2. SSEs: Super spread events. COVID-19: Coronavirus disease 2019. SADS: Swine acute diarrhea syndrome. Ro: Basic reproduction number. IQR: Interquartile range. MERS-COV: Middle East Respiratory Syndrome coronavirus. HIV: Human Immunodeficiency virus HBV: (Human) Hepatitis B virus HCV: (Human) Hepatitis C virus ADE: Antigen dependent enhancement DIV: Double Inactivated virus Th: T helper (cell) RT-qPCR: Reverse transcriptase quantitative polymerase chain reaction ACE-II: Angiotensin converting enzyme II MRSA: Methicillin resistant Staphylococcus aureus References 1. Dong N, Yang X, Ye L, Chen K, Chan EW-C, Yang M, et al. Genomic and protein structure modelling anal- ysis depicts the origin and infectivity of 2019-nCoV, a new coronavirus which caused a pneumonia outbreak in Wuhan, China. bioRxiv. 2020;32(1):2020.01.20.913368- 2020.01.20. 2. Petrosillo N, Viceconte G, Ergonul O, Ippolito G, Petersen E. COVID-19, SARS and MERS: are they closely related? Clinical Microbiology and Infection. 2020. 3. Wan Y, Shang J, Graham R, Baric RS, Li F. Receptor Recog- nition by the Novel Coronavirus from Wuhan: an Anal- ysis Based on Decade-Long Structural Studies of SARS Coronavirus. Journal of Virology. 2020;94(7). 4. Lloyd-Smith JO, Schreiber SJ, Kopp PE, Getz WM. Super- spreading and the effect of individual variation on dis- ease emergence. Nature. 2005;438(7066):355-9. 5. Riley S. Transmission Dynamics of the Etiological Agent of SARS in Hong Kong: Impact of Public Health Interven- tions. Science. 2003;300(5627):1961-6. 6. Kucharski AJ, Althaus CL. The role of superspreading in Middle East respiratory syndrome coronavirus (MERS- CoV ) transmission. Eurosurveillance. 2015;20(25). 7. Wong G, Liu W, Liu Y, Zhou B, Bi Y, Gao GF. MERS, SARS, and Ebola: The Role of Super-Spreaders in Infectious Disease. Cell Host & Microbe. 2015;18(4):398-401. 8. Adegboye OA, Elfaki F. Network Analysis of MERS Coro- navirus within Households, Communities, and Hospi- tals to Identify Most Centralized and Super-Spreading in the Arabian Peninsula, 2012 to 2016. Canadian Jour- nal of Infectious Diseases and Medical Microbiology. 2018;2018:1-9. 9. Frieden TR, Lee CT. Identifying and Interrupting Super- spreading EventsâĂŤImplications for Control of Severe Acute Respiratory Syndrome Coronavirus 2. Emerging Infectious Diseases. 2020;26(6). 10. Brooks SK, Webster RK, Smith LE, Woodland L, Wessely S, Greenberg N, et al. The psychological impact of quar- antine and how to reduce it: rapid review of the evidence. The Lancet. 2020;395(10227):912-20. 11. Holt-Lunstad J, Smith TB, Baker M, Harris T, Stephen- son D. Loneliness and Social Isolation as Risk Fac- tors for Mortality. Perspectives on Psychological Science. 2015;10(2):227-37. 12. Pae C-U. Why Systematic Review rather than Narrative Review? Psychiatry Investigation. 2015;12(3):417. 13. Ng SKC. Possible role of an animal vector in the SARS out- break at Amoy Gardens. The Lancet. 2003;362(9383):570- 2. 14. Perlman S, Netland J. Coronaviruses post-SARS: update on replication and pathogenesis. Nature Reviews Micro- biology. 2009;7(6):439-50. 15. Shen Z, Ning F, Zhou W, He X, Lin C, Chin DP, et al. Su- perspreading SARS Events, Beijing, 2003. Emerging In- fectious Diseases. 2004;10(2):256-60. 16. Taguchi F, Matsuyama S. Soluble Receptor Potentiates Receptor-Independent Infection by Murine Coronavirus. Journal of Virology. 2002;76(3):950-8. 17. Woolhouse MEJ, Dye C, Etard JF, Smith T, Charlwood JD, Garnett GP, et al. Heterogeneities in the transmission of infectious agents: Implications for the design of control programs. Proceedings of the National Academy of Sci- ences. 1997;94(1):338-42. 18. Frulloni L, Lunardi C, Simone R, Dolcino M, Scattolini C, Falconi M, et al. Identification of a Novel Antibody Asso- ciated with Autoimmune Pancreatitis. New England Jour- nal of Medicine. 2009;361(22):2135-42. 19. Guarneri F, Guarneri C, Benvenga S. Helicobacter pylori and autoimmune pancreatitis: role of carbonic anhy- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 12 drase via molecular mimicry? Journal of Cellular and Molecular Medicine. 2005;9(3):741-4. 20. Kountouras J, Zavos C, Gavalas E, Tzilves D. Challenge in the Pathogenesis of Autoimmune Pancreatitis: Poten- tial Role of Helicobacter pylori Infection via Molecular Mimicry. Gastroenterology. 2007;133(1):368-9. 21. Zhang D-h, Wu K-l, Zhang X, Deng S-q, Peng B. In silico screening of Chinese herbal medicines with the poten- tial to directly inhibit 2019 novel coronavirus. Journal of Integrative Medicine. 2020;18(2):152-8. 22. Wu F, Zhao S, Yu B, Chen Y-M, Wang W, Song Z-G, et al. A new coronavirus associated with human respiratory dis- ease in China. Nature. 2020;579(7798):265-9. 23. Menachery VD, Yount BL, Debbink K, Agnihothram S, Gralinski LE, Plante JA, et al. A SARS-like cluster of cir- culating bat coronaviruses shows potential for human emergence. Nature Medicine. 2015;21(12):1508-13. 24. Lu R, Zhao X, Li J, Niu P, Yang B, Wu H, et al. Genomic characterisation and epidemiology of 2019 novel coron- avirus: implications for virus origins and receptor bind- ing. The Lancet. 2020;395(10224):565-74. 25. Loewe L, Hill WG. The population genetics of muta- tions: good, bad and indifferent. Philosophical Trans- actions of the Royal Society B: Biological Sciences. 2010;365(1544):1153-67. 26. Yang Y, Peng F, Wang R, Guan K, Jiang T, Xu G, et al. The deadly coronaviruses: The 2003 SARS pandemic and the 2020 novel coronavirus epidemic in China. Journal of Au- toimmunity. 2020;109:102434-. 27. Rojas M, Rodriguez Y, Monsalve DM, Acosta-Ampudia Y, Camacho B, Gallo JE, et al. Convalescent plasma in Covid-19: Possible mechanisms of action. Autoimmunity Reviews. 2020:102554-. 28. Kowalik MM, Trzonkowski P, ÅĄasiÅĎska-Kowara M, Mi- tal A, Smiatacz T, Jaguszewski M. COVID-19 âĂŤ toward a comprehensive understanding of the disease. Cardiology Journal. 2020. 29. Wurtzer S, Marechal V, Mouchel J-M, Moulin L. Time course quantitative detection of SARS-CoV-2 in Parisian wastewaters correlates with COVID-19 confirmed cases. medRxiv. 2020:2020.04.12.20062679-2020.04.12. 30. Zhou P, Fan H, Lan T, Yang X-L, Shi W-F, Zhang W, et al. Fatal swine acute diarrhoea syndrome caused by an HKU2-related coronavirus of bat origin. Nature. 2018;556(7700):255-8. 31. Brown JD. Cannabidiol as prophylaxis for SARS-CoV-2 and COVID-19? Unfounded claims versus potential risks of medications during the pandemic. Research in social & administrative pharmacy: RSAP. 2020. 32. Vidondo B. Amplification of the basic reproduc- tion number in cattle farm networks. PLOS ONE. 2018;13(4):e0191257-e. 33. Liu Y, Gayle AA, Wilder-Smith A, RocklÃűv J. The repro- ductive number of COVID-19 is higher compared to SARS coronavirus. Journal of Travel Medicine. 2020;27(2). 34. Wu JCea. The current treatment landscape of irritable bowel syndrome in adults in Hong Kong: consensus statements. Hong Kong Medical Journal. 2017:641–7. 35. Hong Kong Department of Health. Outbreak of Severe Acute Respiratory Syndrome (SARS) at Amoy Gardens, Kowloon Bay, Hong Kong Main Findings of the Investi- gation. 1993. 36. Legislative Council Select Committee to inquire into the handling of the Severe Acute Respiratory Syndrome out- break by the Government and the Hospital Authority of Hong Kong. 2003. 37. McKinney Kr GYYLTG. Environmental transmission of SARS at Amoy Gardens. J Environ Health. 2006;68(9):26- 30. 38. Al-Tawfiq JA, Rodriguez-Morales AJ. SARS-CoV- 2 (COVID-19). Journal of Hospital Infection. 2020;105(2):111-2. 39. Forster P, Forster L, Renfrew C, Forster M. Phylogenetic network analysis of SARS-CoV-2 genomes. Proceedings of the National Academy of Sciences. 2020;117(17):9241- 3. 40. Rasche A, Sander A-L, Corman VM, Drexler JF. Evolution- ary biology of human hepatitis viruses. Journal of Hepa- tology. 2019;70(3):501-20. 41. Taguchi F. Coronavirus Receptors. Boston, MA: Springer US; 2005. p. 821-31. 42. Wei WE, Li Z, Chiew CJ, Yong SE, Toh MP, Lee VJ. Presymptomatic Transmission of SARS-CoV-2 âĂŤ Singa- pore, January 23–March 16, 2020. MMWR Morbidity and Mortality Weekly Report. 2020;69(14):411-5. 43. Gu Y. Pandemic (H1N1) 2009 Transmission during Presymptomatic Phase, Japan. Emerging Infectious Dis- eases. 2011;17(9):1737-9. 44. Thompson RN, Gilligan CA, Cunniffe NJ. Detecting Presymptomatic Infection Is Necessary to Forecast Major Epidemics in the Earliest Stages of Infectious Disease Outbreaks. PLOS Computational Biology. 2016;12(4):e1004836-e. 45. RocklÃűv J, Sjodin H, Wilder-Smith A. COVID-19 out- break on the Diamond Princess cruise ship: estimating the epidemic potential and effectiveness of public health countermeasures. Journal of Travel Medicine. 2020. 46. Wang C, Liu L, Hao X, Guo H, Wang Q, Huang J, et al. Evolving Epidemiology and Impact of Non- pharmaceutical Interventions on the Outbreak of Coro- navirus Disease 2019 in Wuhan, China. medRxiv. 2020:2020.03.03.20030593-2020.03.03. 47. Gao Y, Yan L, Huang Y, Liu F, Zhao Y, Cao L, et al. Structure of the RNA-dependent RNA polymerase from COVID-19 This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 13 Archives of Academic Emergency Medicine. 2020; 8(1): e74 virus. Science. 2020:eabb7498-eabb. 48. Goldhill DH, te Velthuis AJW, Fletcher RA, Langat P, Zam- bon M, Lackenby A, et al. The mechanism of resistance to favipiravir in influenza. Proceedings of the National Academy of Sciences. 2018;115(45):11613-8. 49. Forni D, Filippi G, Cagliani R, De Gioia L, Pozzoli U, Al- Daghri N, et al. The heptad repeat region is a major selec- tion target in MERS-CoV and related coronaviruses. Sci- entific Reports. 2015;5(1):14480-. 50. Tang H, Liu Y, Huang G. Current Status and Development Strategy for Community-Supported Agriculture (CSA) in China. Sustainability. 2019;11(11):3008-. 51. howell Gea. Transmission characteristics of MERS and SARS in the healthcare setting: a comparative study. BMC Medicine. 2015;13(1):210. 52. Gormley Mea. Pathogen cross-transmission via building sanitary plumbing systems in a full scale pilot test-rig. PLOS ONE. 2017;12(2):e0171556. 53. Lau Y-L. SARS: future research and vaccine. Paediatric Respiratory Reviews,. 2004;5(4):300-3. 54. Li Yea. Predicting super spreading events during the 2003 severe acute respiratory syndrome epidemics in Hong Kong and Singapore. American journal of epidemiology,. 2004; 160(8):719–28. 55. Shaw K. The 2003 SARS outbreak and its impact on infec- tion control practices. Public Health. 2006;120(1):8-14. 56. Cave E. COVID-19 Super-spreaders: Definitional Quandaries and Implications. Asian Bioethics Review. 2020;12(2):235-42. 57. Xu X-Kea. Reconstruction of Transmission Pairs for Novel Coronavirus Disease 2019 (COVID-19) in Mainland China: Estimation of Superspreading Events, Serial Inter- val, and Hazard of Infection. Clinical Infectious Diseases. 2020. 58. Kwok KOea. Inferring super-spreading from transmis- sion clusters of COVID-19 in Hong Kong, Japan, and Sin- gapore. Journal of Hospital Infection. 2020;105(4):682-5. 59. Chau T-N, Lee K-C, Yao H, Tsang T-Y, Chow T-C, Ye- ung Y-C, et al. SARS-associated viral hepatitis caused by a novel coronavirus: Report of three cases. Hepatology. 2004;39(2):302-10. 60. Tu Y-F, Chien C-S, Yarmishyn AA, Lin Y-Y, Luo Y-H, Lin Y- T, et al. A Review of SARS-CoV-2 and the Ongoing Clin- ical Trials. International Journal of Molecular Sciences. 2020;21(7):2657-. 61. Luk HKH, Li X, Fung J, Lau SKP, Woo PCY. Molecular epidemiology, evolution and phylogeny of SARS coron- avirus. Infection, Genetics and Evolution. 2019;71:21-30. 62. Li Y-H, Hu C-Y, Wu N-P, Yao H-P, Li L-J. Molecular Charac- teristics, Functions, and Related Pathogenicity of MERS- CoV Proteins. Engineering. 2019;5(5):940-7. 63. Weiss SR, Navas-Martin S. Coronavirus Pathogenesis and the Emerging Pathogen Severe Acute Respiratory Syn- drome Coronavirus. Microbiology and Molecular Biology Reviews. 2005;69(4):635-64. 64. Mousavizadeh L, Ghasemi S. Genotype and phenotype of COVID-19: Their roles in pathogenesis. Journal of Micro- biology, Immunology and Infection. 2020. 65. Hu B, Ge X, Wang L-F, Shi Z. Bat origin of human coron- aviruses. Virology Journal. 2015;12(1):221-. 66. Knobler S MALS. The impact of SARS epidemic. Wash- ington, D.C.: National Academies Press; 2004. 67. Lee Jw MWJ. Estimating the global economic costs of SARS. Washington, D.C.: National Academies Press; 2004. 68. Kingston D. Memorandum on the infections hazards of the common communion cup with especial reference to aids. European Journal of Epidemiology. 1988;4(2):164- 70. 69. Gill ON. The hazard of infection from the shared commu- nion cup. Journal of Infection. 1988;16(1):3-23. 70. Pellerin J, Edmond MB. Infections associated with re- ligious rituals. International Journal of Infectious Dis- eases. 2013;17(11):e945-e8. 71. Corstjens PLAM, Abrams WR, Malamud D. Saliva and vi- ral infections. Periodontology 2000. 2016;70(1):93-110. 72. Pintilie H, Brook G. Commentary: A review of risk of hep- atitis B and C transmission through biting or spitting. Journal of Viral Hepatitis. 2018;25(12):1423-8. 73. Peng X, Xu X, Li Y, Cheng L, Zhou X, Ren B. Transmission routes of 2019-nCoV and controls in dental practice. In- ternational Journal of Oral Science. 2020;12(1):9-. 74. Xu R, Cui B, Duan X, Zhang P, Zhou X, Yuan Q. Saliva: po- tential diagnostic value and transmission of 2019-nCoV. International Journal of Oral Science. 2020;12(1):11-. 75. Kidd-Ljunggren K, Holmberg A, BlÃd’ckberg J, Lindqvist B. High levels of hepatitis B virus DNA in body flu- ids from chronic carriers. Journal of Hospital Infection. 2006;64(4):352-7. 76. Kountouras J TEMSSCTGPA, et al. Experience of ente- cavir administration in patients with chronic hepati- tis B. Annals of gastroenterology. 2010;23 (Suppl)(57 (in Greek)). 77. AminJafari A, Ghasemi S. The possible of immunother- apy for COVID-19: A systematic review. International Im- munopharmacology. 2020;83:106455-. 78. Dimmock K ENJLAJ. Introduction to modern virology. Blackwell ed. New York, NY2007. 65- p. 79. Saif LJ. Animal coronavirus vaccines: Lessons for SARS. Developments in Biologicals. 2005;119:129-40. 80. Jimenez-Guardeno JM, Regla-Nava JA, Nieto-Torres JL, DeDiego ML, Castano-Rodriguez C, Fernandez-Delgado R, et al. Identification of the Mechanisms Causing Re- version to Virulence in an Attenuated SARS-CoV for the This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem A. M. Kyriakopoulos et al. 14 Design of a Genetically Stable Vaccine. PLOS Pathogens. 2015;11(10):e1005215-e. 81. Bolles M, Deming D, Long K, Agnihothram S, Whit- more A, Ferris M, et al. A Double-Inactivated Se- vere Acute Respiratory Syndrome Coronavirus Vac- cine Provides Incomplete Protection in Mice and In- duces Increased Eosinophilic Proinflammatory Pul- monary Response upon Challenge. Journal of Virology. 2011;85(23):12201-15. 82. Peeples L. News Feature: Avoiding pitfalls in the pur- suit of a COVID-19 vaccine. Proceedings of the National Academy of Sciences. 2020;117(15):8218-21. 83. Sheahan T, Whitmore A, Long K, Ferris M, Rockx B, Funkhouser W, et al. Successful Vaccination Strategies That Protect Aged Mice from Lethal Challenge from Influenza Virus and Heterologous Severe Acute Res- piratory Syndrome Coronavirus. Journal of Virology. 2011;85(1):217-30. 84. Spruth M, Kistner O, Savidis-Dacho H, Hitter E, Crowe B, Gerencer M, et al. A double-inactivated whole virus candidate SARS coronavirus vaccine stimulates neu- tralising and protective antibody responses. Vaccine. 2006;24(5):652-61. 85. Yap FHY, Gomersall CD, Fung KSC, Ho PL, Ho OM, Lam PKN, et al. Increase in Methicillin-Resistant Staphylo- coccus aureus Acquisition Rate and Change in Pathogen Pattern Associated with an Outbreak of Severe Acute Respiratory Syndrome. Clinical Infectious Diseases. 2004;39(4):511-6. 86. Hotez PJ, Bottazzi ME, Corry DB. The potential role of Th17 immune responses in coronavirus immunopathol- ogy and vaccine-induced immune enhancement. Mi- crobes and Infection. 2020. 87. Wu D, Yang XO. TH17 responses in cytokine storm of COVID-19: An emerging target of JAK2 inhibitor Fedra- tinib. Journal of Microbiology, Immunology and Infec- tion. 2020. 88. Chow SCS. Specific epitopes of the structural and hypothetical proteins elicit variable humoral re- sponses in SARS patients. Journal of Clinical Pathology. 2006;59(5):468-76. 89. Melsew YA, Gambhir M, Cheng AC, McBryde ES, Den- holm JT, Tay EL, et al. The role of super-spreading events in Mycobacterium tuberculosis transmission: ev- idence from contact tracing. BMC Infectious Diseases. 2019;19(1):244-. 90. Drobeniuc J, Greene-Montfort T, Le N-T, Mixson- Hayden TR, Ganova-Raeva L, Dong C, et al. Laboratory- based Surveillance for Hepatitis E Virus Infection, United States, 2005–2012. Emerging Infectious Diseases. 2013;19(2):218-22. 91. Komas NP, Ghosh S, Abdou-Chekaraou M, Pradat P, Al Hawajri N, Manirakiza A, et al. Hepatitis B and hepati- tis D virus infections in the Central African Republic, twenty-five years after a fulminant hepatitis outbreak, in- dicate continuing spread in asymptomatic young adults. PLOS Neglected Tropical Diseases. 2018;12(4):e0006377- e. 92. Chan C-Mea. Carcinoembryonic Antigen-Related Cell Adhesion Molecule 5 Is an Important Surface Attachment Factor That Facilitates Entry of Middle East Respiratory Syndrome Coronavirus. Journal of Virology Edited by S Perlman. 2016;90(20):9114–27. 93. Mothes Wea. Virus Cell-to-Cell Transmission. Journal of Virology. 2010; 84(17):8360–8. 94. Peiris Jea. Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study’. The Lancet. 2003;361(9371):1767–72. 95. Spiegel Mea. Interaction of severe acute respiratory syndrome-associated coronavirus with dendritic cells. The Journal of general virology. 2006;87(7):1953–60. 96. Chen MIC LS-C, Leong H-N, Leo Y-S. . Understanding the super-spreading events of SARS in Singapore. Ann Acad Med Singapore 2006;35:390–4. 97. Sung JJY YI, Zhong NS, Tsoi K. . Super-spreading events of SARS in a hospital setting: who, when, and why? . Hong Kong Med J = Xianggang yi xue za zhi 2009;15(Suppl 8):29–33. 98. Stein RA. Super-spreaders in infectious diseases. Interna- tional Journal of Infectious Diseases. 2011;15(8):e510-e3. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Method Results Discussion Limitations Conclusion Declarations References