key: cord-319129-o1kzb6dm
authors: Peng, Jianhui; Su, Dongwei; Zhang, Ziwei; Wang, Mingke
title: Identification and management of asymptomatic carriers of coronavirus disease 2019 (COVID‐19) in China
date: 2020-06-08
journal: Influenza Other Respir Viruses
DOI: 10.1111/irv.12768
sha: 
doc_id: 319129
cord_uid: o1kzb6dm

nan

To the Editor,

We read with interest the recent article by Yu transmission through asymptomatic carriers has been a huge challenge for COVID-19 prevention and control. 1 There are two types of asymptomatic carriers: those who never develop symptoms and those who are detected during the incubation period (pre-symptomatic detection) prior to symptom onset. 3 Here, we discussed the identification and management of asymptomatic carriers of COVID-19 in China.

So far, asymptomatic carriers of COVID-19 may be found by the following ways. 3 Since April 1, 2020, the number of asymptomatic infectors has been reported online by National Health Commission of the People's Republic of China on a daily basis, and the following management measures were required to be carried out to minimize the risk of their transmission in China. 3 First, persons detected as asymptomatic infectors would be isolated for 14 days, which may prevent them from becoming contagion sources. Those can be lifted from isolation by negative nucleic acid tests on two consecutive samples at least 24 hours apart. 3 Second, epidemiological investigation of asymptomatic infectors would be strengthened, and strict disinfection would be implement in their living places such as homes, medical institutions, isolation wards, transport tools, and medical observation places. Third, since early detection of asymptomatic carriers is critical to contain their transmission, current screening methods also need to be strengthened. Nucleic acid screening is practical and quick for the population. However, due to specimen collection, testing methods, product stability, false-negative results have been frequently reported, which will hamper case detection and disease control. 8 Therefore, multiple screening and monitoring of nucleic acid combining with antigens and antibodies in blood and other body fluids are recommended. 8 At present, persons who are significant epidemiological associations with COVID-19 patients (eg, close contacts) will be put under 14-day centralized medical observation in China. 3 As the epidemic enters a new stage, in order to consolidate the previous anti-epidemic achievements and prevent the epidemic from rebounding, we should further strengthen the monitoring of asymptomatic carriers and some special populations who may play a greater role in the spread of COVID-19, including front-line medical staff, disease control personnel, street epidemic prevention and control point staff, and delivery personnel. Since asymptomatic carriers have no clinical symptoms, they are difficult to identify, diagnose, and isolate. This can lead to loopholes in prevention and control measures, resulting in increased difficulty in controlling the spread of COVID-19. 9 The public health education should be strengthened, and formation of good hygiene habits is important. In particular, awareness of self-protection, self-supervision and administration, and pre-service training of above special populations are critical to reducing the spread of asymptomatic infections.

In future, further definition of high-risk populations and development of effective screening strategies and programs will support rapid identification and management of asymptomatic carrier transmission of COVID-19. 9 Further study is needed on asymptomatic carriers including their frequency relative to symptomatic infections, their disease course, and factors associated with having an asymptomatic rather than symptomatic infection. 8 Since there can be a gray area between asymptomatic and symptomatic infections, Verification: All authors have seen the manuscript and agree to the content. All the authors played a significant role in the paper.

COVID-19 transmission through asymptomatic carriers is a challenge to containment. Influenza Other Respir Viruses

Covert coronavirus infections could be seeding new outbreaks

Joint Taskforce on COVID-19 Prevention and Control, China State Council. Protocol for the management of asymptomatic persons infected with COVID-19 virus

Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing

Presumed asymptomatic carrier transmission of COVID-19

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SARS-CoV-2 viral load in upper respiratory specimens of infected patients

Screening and management of asymptomatic infection of corona virus disease 2019 (COVID-19)

Advances on presymptomatic or asymptomatic carrier transmission of COVID-19


