key: cord-343759-me0n2k3f
authors: Majiya, H.; Aliyu-Paiko, M.; Balogu, V. T.; Musa, D. A.; Salihu, I. M.; Kawu, A. A.; Bashir, I. Y.; Sani, A. R.; Baba, J.; Muhammad, A. T.; Jibril, F. L.; Bala, E.; Obaje, N. G.; Aliyu, Y. B.; Muhammad, R. G.; Mohammed, H.; Gimba, U. N.; Uthman, A.; Liman, H. M.; Alhaji, S. A.; James, J. K.; Makusidi, M. M.; Isah, M. D.; Abdullahi, I.; Ndagi, U.; Waziri, B.; Bisallah, C. I.; Dadi-Mamud, N. J.; Ibrahim, K.; Adamu, A. K.
title: Seroprevalence of COVID-19 in Niger State
date: 2020-08-05
journal: nan
DOI: 10.1101/2020.08.04.20168112
sha: 
doc_id: 343759
cord_uid: me0n2k3f

Coronavirus Disease 2019 (COVID-19) Pandemic is ongoing, and to know how far the virus has spread in Niger State, Nigeria, a pilot study was carried out to determine the COVID-19 seroprevalence, patterns, dynamics, and risk factors in the state. A cross sectional study design and clustered-stratified-Random sampling strategy were used. COVID-19 IgG and IgM Rapid Test Kits (Colloidal gold immunochromatography lateral flow system) were used to determine the presence or absence of antibodies to SARS-CoV-2 in the blood of sampled participants across Niger State as from 26th June 2020 to 30th June 2020. The test kits were validated using the blood samples of some of the NCDC confirmed positive and negative COVID-19 cases in the State. COVID-19 IgG and IgM Test results were entered into the EPIINFO questionnaire administered simultaneously with each test. EPIINFO was then used for both the descriptive and inferential statistical analyses of the data generated. The seroprevalence of COVID-19 in Niger State was found to be 25.41% and 2.16% for the positive IgG and IgM respectively. Seroprevalence among age groups, gender and by occupation varied widely. A seroprevalence of 37.21% was recorded among health care workers in Niger State. Among age groups, COVID-19 seroprevalence was found to be in order of 30-41 years (33.33%) > 42-53 years (32.42%) > 54-65 years (30%) > 66 years and above (25%) > 6-17 years (19.20%) > 18-29 years (17.65%) > 5 years and below (6.66%). A seroprevalence of 27.18% was recorded for males and 23.17% for females in the state. COVID-19 asymptomatic rate in the state was found to be 46.81%. The risk analyses showed that the chances of infection are almost the same for both urban and rural dwellers in the state. However, health care workers and those that have had contact with person (s) that travelled out of Nigeria in the last six (6) months are twice ( 2 times) at risk of being infected with the virus. More than half (54.59%) of the participants in this study did not practice social distancing at any time since the pandemic started. Discussions about knowledge, practice and attitude of the participants are included. The observed Niger State COVID-19 seroprevalence means that the herd immunity for COVID-19 is yet to be achieved and the population is still susceptible for more infection and transmission of the virus. If the prevalence stays as reported here, the population will definitely need COVID-19 vaccines when they become available. Niger State should fully enforce the use of face/nose masks and observation of social/physical distancing in gatherings including religious gatherings in order to stop or slow the spread of the virus.

1 and inferential statistical analyses of the data generated. The seroprevalence of COVID-19 in Niger State was found to be 25.41% and 2.16% for the positive IgG and IgM respectively.

Seroprevalence among age groups, gender and by occupation varied widely. A seroprevalence of 37.21% was recorded among health care workers in Niger State. Among age groups, COVID-19 seroprevalence was found to be in order of 30-41 years (33.33%) > 42-53 years (32.42%) > 54-65 years (30%) > 66 years and above (25%) > 6-17 years (19.20%) > 18-29 years (17.65%) > 5 years and below (6.66%). A seroprevalence of 27.18% was recorded for males and 23.17% for females in the state. COVID-19 asymptomatic rate in the state was found to be 46.81%. The risk analyses showed that the chances of infection are almost the same for both urban and rural dwellers in the state. However, health care workers and those that have had contact with person (s) that travelled out of Nigeria in the last six (6) months are twice ( 2 times) at risk of being infected with the virus. More than half (54.59%) of the participants in this study did not practice social distancing at any time since the pandemic started. Discussions about knowledge, practice and attitude of the participants are included. The observed Niger State COVID-19 seroprevalence means that the herd immunity for COVID-19 is yet to be achieved and the population is still susceptible for more infection and transmission of the virus.

If the prevalence stays as reported here, the population will definitely need COVID-19 vaccines when they become available. Niger State should fully enforce the use of face/nose masks and observation of social/physical distancing in gatherings including religious gatherings in order to stop or slow the spread of the virus. Pandemic is caused by a novel coronavirus-SARS-CoV-2 that is believed to have crossed from bats to humans for the first time (Rothan & Byrareddy, 2020; Lai et al., 2020; Shereen et al., 2020) . COVID-19 is an infectious disease of respiratory system of humans and animals and the virus can be transmitted through facial openings which include mouth, nostrils and maybe eyes (Lai et al., 2020; Shereen et al., 2020; Wu et al., 2020) .

The first case of COVID-19 in Niger State, Nigeria was announced by the NCDC on 10 th April 2020; this was after about six (6) weeks when the first confirmed case (index case) of COVID-19 in Nigeria was announced on 27 th February 2020 when a foreigner in Lagos tested positive . CC-BY-ND 4.0 International license It is made available under a perpetuity.

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The copyright holder for this this version posted August 5, 2020 . . https://doi.org/10.1101 for SARS-CoV-2. Since then, many cases have been confirmed for the state and it is still increasing.

Coronavirus Disease 2019 , like most of infectious diseases, the isolation of the aetiologic agent-SARS CoV-2 through tissue/cell plate culture technique would have been the gold standard method for the diagnostic test. However, plate culturing is usually laborious, time consuming, complex and costly and therefore impossible to use especially for epidemiological studies where large samples may be involved. Also, even though Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) have been predominantly used to test for the agent of COVID-19 world over including Nigeria (WHO, 2020a; 2020b) , it is laborious, time consuming, costly and complex.

Infection by many pathogens including viruses do elicit production of antibodies in humans and animals even if no symptoms manifested. The detection of the antibodies in the whole blood/serum/plasma of humans and animals have been used as preliminary diagnoses of infectious diseases (WHO, 2020a (WHO, , 2020b 2020c; Xiao et al., 2020) . Also because of the relative ease of use and simplicity of the antigen-antibodies test kits compared to cell/tissue culture and PCR, they are mostly used in the epidemiological studies to determine infectious diseases prevalence, patterns, dynamics, and risk factors (WHO, 2020a (WHO, , 2020b Xiao et al., 2020) .

Antigen-Antibody based kits unlike other methods can detect previous exposure to the infectious agents (WHO, 2020a; 2020b; 2020c; Xiao et al., 2020 )-this information is very important especially in COVID-19 with assumed high rate of asymptomatic cases in order to see how far the virus has spread and infection patterns, effectiveness of social distancing measures enforced and determination of herd immunity to the disease to know the extent of vaccination to do when COVID-19 vaccines become available. This study was aimed at determining the COVID-19 prevalence, patterns and dynamics and risk factors for contracting the disease in Niger State.

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The copyright holder for this this version posted August 5, 2020. IgG/IgM Rapid Test (Whole Blood/ Serum/Plasma) is a rapid chromatographic immunoassay for the qualitative detection of IgG and IgM antibodies to COVID-19 in human whole blood, serum or plasma as an aid in the diagnosis of primary and secondary COVID-19 infections.

Sterile lancets, cotton wool, face masks, hand gloves, methylated spirit, dustbin, dustbin bags, material transportation bags were all locally purchased. Also, three (3) laptops with EPIINFO 7.2.2.6 software installed were used: one laptop for each of the three (3) geopolitical zones of Niger State, Nigeria.

Ethical approval (STA/495/Vol/152) for this study was given by the Research Ethics Committee of the Niger Sate Ministry of Health. Consents were also sought from each of the participants prior to tests and questionnaire administration, and only those individuals that have given full consent were used in the study. Parents/Guardians were responsible for the consents of their wards that participated in the study and were under 18 of age.

The study area was Niger State and its residents were the study population ( Figure 1 ). Niger State ( Figure 1 ) is one of the federating geopolitical states in Nigeria. It has Minna as its capital.

Other major towns are Bida, Kontagora, Suleja, New Bussa, Mokwa, Lapai, and Agaie. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint A cross sectional study design and clustered-stratified-random sampling strategy were used.

The three (3) geopolitical zones (Zone A, Zone B and Zone C) in the state were covered fairly ( Figure 1 ). Places of residents (classified as urban and rural), gender, occupation, age group/range, were the stratifications that were applied in those places chosen in each of the zones (Figure 1 ). With full consent to participate in the study, samples were taken randomly from 185 participants for COVID-19 IgG and IgM Rapid Tests and questionnaire (created by EPIINFO 7.2.2.6) administered simultaneously. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

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The COVID-19 IgG and IgM Rapid Test Kits were validated with the blood samples of those individuals that were confirmed by the NCDC through PCR as positive and or negative for 

COVID-19 IgG/IgM Rapid Tests were carried out using the whole blood of the participants.

It is qualitative membrane-based immunoassay for the detection of COVID 19 antibodies in whole blood. The tests were carried out and interpreted according to the kits manufacturer's instruction. The test result of each participant was recorded and entered into the EPIINFO questionnaire administered for that particular participant.

In order to be able to determine the COVID-19 prevalence, patterns and dynamics and risk factors for contracting the disease in Niger State, a questionnaire (See Supplementary 2) was designed and created using EPIINFO 7.2.2.6. The questionnaire was designed to ask some . CC-BY-ND 4.0 International license It is made available under a perpetuity.

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The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint questions with categorical responses (Yes or No) and also to accommodate the test results of the participants; this was to be able to run 2x2 table statistics including calculating infection risk ratios for many scenarios. COVID-19 IgG and IgM Test results were entered into the EPIINFO questionnaire administered simultaneously with each test for a participant. EPIINFO was used for both the descriptive and inferential statistical analyses of the data generated. Bar charts were plotted in Origin Pro 2019b (9.65).

A cross sectional study design and clustered-stratified-random sampling method were used to choose 185 participants across Niger State for this study that was aimed at determining the COVID-19 seroprevalence, patterns, dynamics, and risk factors in the state. Although the sample size is small, the sampling strategy employed made it a true representative of the state.

The demographic characteristics of the participants in this study are shown in Figure Considering other demographic characteristics of the participants, male and female participants in this study stood at 55.68% and 44.32% respectively (Figure 2 B) . The gender of the participants also reflected the ratio of male to female in Nigeria which is 50.6% male to 49.4% female currently (Figure 2 B) (Countrymeters, 2020) . The percentage of participants that were urban dwellers in this study was 62.16% while for the rural dwellers, it was 37.86% ( is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint rural areas (Worldmeters, 2020) . Also, the participants in this study were categorised either as health care worker (23.24%) or non-health care worker (76.76%) (Figure 2 D) . Among health care participants, males constituted 51.16% while 48.84% were females (Figure 2 E) .

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COVID-19 Pandemic is ongoing and at the moment, no available vaccines for the disease. For now, the reliable ways of preventing the transmission of the SARS-CoV-2 (the causative agent of COVID-19 Pandemic) among human populations are social/physical distancing measures and good sanitation and hygiene practices. Adherence to these COVID-19 preventive measures should be impacted by the knowledge and beliefs of people about the disease since the measures involve some behavioural changes and practice. People can only believe what they know (aware of) and can practice when they believe.

In order to assess the knowledge, attitude and practice of the participants with regards to COVID-19 in Niger State, the participants were asked whether they know and believed that the disease is in the state. They were also asked about their adherence to the social distancing and face and hand hygiene. Overwhelming majority of the participants (81.62%) were aware and know about COVID-19 pandemic (Figure 3 A) . However, only 58.92% of the participants believed that the disease is in Niger State while 41.08% did not believe (Figure 3 B) . More than half (54.59%) of the participants in this study did not practice social distancing (Figure 3 C) at any time since the pandemic started even as the lockdown was once enforced in the state.

Majority (61.62) of the participants practiced hand and face hygiene (Figure 3 D) .

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The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint physical distancing and other required COVID-19 control measures may not be observed or enforced (Majiya, 2020) .

The second reason is the prevalence of disbeliefs, myths and conspiracy theories. Many people did not believe in the existence of COVID-19 (Figure 3 B) and especially about the highly contagious nature of the disease. This may be the chief reason why many people did not care to observe social/physical distancing (Figure 3 C) even when not enforced on them at the ATMs, markets, religious gatherings, motor parks, shops, supermarkets etc. Also, myths and conspiracy theories such as COVID-19 does not affect black people, that high environmental temperature and weather will kill off the virus, or that COVID-19 is for rich people and elites are some of the reasons why people are slow in accepting the enormity of the pandemic and therefore usually takes observance of social and physical distancing lightly (Majiya, 2020) .

Thirdly, no efficient and robust housing and biometric data management systems where everyone is accounted for, especially for the purposes of employment, health, security and social welfare. If these are available, foods and other goods purchased online can be sent to houses with ease. In addition, utilities such as power, water, internet etc, are in most cases not provided or grossly inadequately supplied. It is difficult for people to stay back at home and observe social/physical distancing in such situations (Majiya, 2020) .

The first confirmed case (index case) of COVID-19 in Nigeria was announced on 27 th February 2020 when a foreigner in Lagos tested positive for SARS-CoV-2. Soon after that, many people including the contacts of the index case and those that came back into the country and their contacts tested positive for the virus. Although overseas travel prior to the border closures and lockdowns in Nigeria has been associated with the increased chance/risk of contracting COVID-19, this might have changed overtime to more of community transmission of the virus.

Participants in this study were asked whether they travelled out or have had contact with . CC-BY-ND 4.0 International license It is made available under a perpetuity.

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The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint someone that travelled out of Nigeria since when the pandemic started (last 6 months). Also, the participants were asked whether they have had flu-like experience in the last 6 months since when the COVID-19 index case was announced in Nigeria; this can help deduce the rate of COVID-19 asymptomatic rate in Niger State. Vast majority (97.84%) of the participants did not travel out of Nigeria since the beginning of the year when the pandemic started (Figure 4 A). Only very few (2.16%) of the participants did travel out of Nigeria in the last 6 months and have returned (Figure 4 A) . However, more (12.97%) of the participants have had contact with someone that travelled out of the country in the last 6 months (Figure 4 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint 

system) were used to determine the presence or absence of antibodies to SARS-CoV-2 in the blood of sampled participants across the Niger State as from 26 th June 2020 to 30 th June 2020.

The test kits were validated using the blood samples of some of the NCDC confirmed positive and negative COVID-19 cases in the State. All the ten (10) confirmed NCDC positive cases sampled tested positive for the IgG for SARS-CoV-2 while all the five (5) confirmed NCDC negative individuals (that have never tested positive before) tested negative for the IgG and is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020 . . https://doi.org/10.1101 IgM for the SARS-CoV-2. This means that 100% sensitivity and specificity were observed for the test kits used in the study.

The seroprevalence of COVID-19 in Niger State was found to be 25.41% and 2.16% for the positive IgG and IgM respectively as at when the sampling and tests were carried out ( The number of participants that did not experienced flu-like symptoms in the last 6 months and have tested positive for SARS-CoV-2 IgG amounted to the COVID-19 complete asymptomatic rate in Niger State (Figure 5 B) . The COVID-19 asymptomatic rate in the state was found to be 46.81% (Figure 5 B) . It has been reported that majority of infected people SARS-CoV-2 (about 50-75%) are usually asymptomatic (Day, 2020; Nishiura et al; . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint COVID-19 seroprevalence among age groups, gender and by occupation varied widely ( Figure   6 ). Among age groups, the COVID-19 seroprevalence was found to be in order of 30-41 years (33.33%) > 42-53 years (32.42%) > 54-65 years (30%) > 66 years and above (25%) > 6-17 years (19.20%) > 18-29 years (17.65%) > 5 years and below (6.66%) (Figure 6 A) . A seroprevalence of 27.18% was recorded for males and 23.17% for females in the state (Figure   6 B). The seroprevalence among the age groups and gender correlated with the most mobile/active of the age groups and gender in our society. Age groups 30-41 years, 42-53 years and 54-65 years are the most mobile of the age groups while men are more mobile than the women and therefore can contract the virus easily. Generally, around the world, the case fatality of COVID-19 varied widely (1-20%) with more cases and fatalities observed in males compared to females (Baud et al., 2020) . Seroprevalence of 37.21% was recorded for health care workers in Niger State (Figure 6 C) . Among the non-health care workers in the state, the seroprevalence recorded was 19.01% (Figure 6 C) . It is expected for the health care workers to have higher COVID-19 prevalence compared to the non-health care workers because they are the frontline workers responsible for the diagnosis, treatment, and management of patients is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint including symptomatic and asymptomatic COVID-19 patients. COVID-19 seroprevalence among the urban dwellers in the state stood at 27.82% while for the rural dwellers, it was 21.42% (Figure 6 D) . The same COVID-19 seroprevalence (about 25%) was recorded among the overseas returnees and those that did not travel (Figure 6 E) . However, a higher COVID-19 seroprevalence (41.68%) was recorded for those that had contact with the overseas returnees compared to those that did not have contact with the returnees (22.98%) (Figure 6 F) .

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In order to determine the risk factors of COVID-19 and also the effectiveness of COVID-19 preventive measures enforced in the state, 2x2 table statistics was used to calculate odd and risk ratios for many scenarios (Table 1) . When gender of the participants and Positive COVID-19 IgG results were cross tabulated, the risk ratio recorded for female participants was 0.8524 (Table 1 ). This means that being a female is a protective factor against the infection of SARS-CoV-2 in Niger State. This also correlated with the COVID-19 Seroprevalence recorded among males and females participants (Figure 6 B) . The less risk of infection by the females in this study maybe due to the physical attributes such as the less mobility and activity of the females compared to that of males in our society.

The risk analyses showed that the chances of infection are almost the same for both urban and rural dwellers in the state even though COVID-19 Seroprevalence among urban dwellers was a little higher than that of rural dwellers (Table 1 and is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint Health care workers and those that had contact with person (s) that travelled out of Nigeria in the last six (6) months are twice ( 2 times) at risk of being infected with the virus (Table 1) .

However, the risk analyses showed that returning from the overseas did not conferred a protection or posed any increased risk of contracting the virus (Table 1) . World over, health care workers are the frontline workers for the diagnosis, treatment, and management of COVID-19 Patients. These enormous essential tasks for controlling the COVID-19 Pandemic coupled with the inadequate or lack of PPE in some instances and high asymptomatic rate of COVID-19 among people put the health care workers at greater risk of contracting and transmitting the disease. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint are almost the same for both urban and rural dwellers in the state. However, health care workers and those that had contact with person (s) that travelled out of Nigeria in the last six (6) months are twice ( 2 times) at risk of being infected with the virus. More than half (54.59%) of the participants in this study did not practiced social distancing at any time since the pandemic started. The observed Niger State COVID-19 seroprevalence means that herd immunity for the COVID-19 is yet to be achieved and the population is still susceptible for more infection and transmission of the virus.

Although Niger State is out of the enforced lockdown, the COVID-19 cases keep increasing because the population is still susceptible for more infection and transmission of SARS-CoV-2. This study shows that the virus is already here, and we must find ways of living with it such that it caused no or minimal human and socioeconomic losses in Niger State and Nigeria as a whole. Since this study recorded high COVID-19 asymptomatic rate in the state as well as observed mild symptomatic cases of COVID-19 in the communities, isolation and quarantine centers with no fatality, going back to the lockdown should never again be entertained.

However, the state should fully enforce the use of face/nose masks and observation of social/physical distancing in gatherings including socioeconomic and religious gatherings in order to stop or slow the spread of the virus. PPEs should be made adequately available for all the health care workers in the state. If the prevalence stays as reported in this study, the population will need COVID-19 vaccines when they become available.

The sample size used in this pilot study is small although very representative of the state due to the sampling strategy employed. The COVID-19 Rapid Tests Kits that are suitable for epidemiological studies are highly costly. More COVID-19 seroprevalence surveys that can have larger sample size are required and monthly surveys for the next 8 months to determine the rate of infection among the state residents is also needed. Validated COVID-19 Rapid Test . CC-BY-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted August 5, 2020. . https://doi.org/10.1101/2020.08.04.20168112 doi: medRxiv preprint

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This work was funded by the Ibrahim Badamasi Babangida University, Lapai, Niger State, Nigeria. The research team would like to thank the Niger State Ministry of Health for their support throughout the study.

Names, latitude, and longitude of the of the sampling and testing points 
