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Covid-19 and community mitigation strategies in a pandemic

BMJ 2020; 368 doi: https://doi.org/10.1136/bmj.m1066 (Published 17 March 2020) Cite this as: BMJ 2020;368:m1066

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Rapid Response:

Need for Social distancing and self isolation during COVID 19 pandemic

Dear Editor

It is now well known that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads through close contact via droplets or aerosols when an infected person coughs directly onto the face of another person in close proximity. It is known that aerosols travel up to a distance of one metre or nearly three feet during sneezing or coughing. The portals of entry being exposed mucous membranes such as in the eyes, nose, mouth. Hands infected after touching contaminated surfaces can transfer the virus directly to mouth or during touching of the face or eye. Understanding survival period of the virus in the environment is of importance while instituting preventive measures.

Observation of the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shows that the virus remains stable up to three hours in aerosols and up to four hours on copper, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel surfaces (1).

Further, the incubation period of the virus is reported to be 0-14 days. Considering the longest period viz. 14 days and period of communicability within this period, even if the infected person or asymptomatic carrier is kept isolated and social distancing of at least 1.5 metres (2) or still better, if it is for a distance of 6 feet (3), then chances of transmission of the virus would be minimal. The virus, if spread through aerosols, will not survive in the environment beyond this period of 14 days. Such an inference seems logical for disrupting transmission of the virus. Further, there is emerging evidence that new cases of SARS-CoV-2 in China have dropped to zero nearly eight weeks after following strict massive quarantine of about 60 million people in Hubei province (4).

The model followed by South Korea, which involved extensive testing and contact tracing, might not be feasible in resource poor countries such as India, where facilities for testing are limited and infected people tend to hide their infection till they become symptomatic, by which time the virus might have spread to many close contacts.

Under the prevailing conditions and circumstances, total lockdown with social distancing and active hand and cough hygiene seems to be the only viable measures for prevention of the transmission of the SARS-CoV-2. Although we need to put in place a case for community surveillance of influenza-like illness with fever and cough as a symptom for identifying the SARS-CoV-2 in future, when the infection spreads in the community. In India, we need to involve frontline workers such as ASHA, Anganwadi workers, Health workers, local volunteers for prompt reporting of suspect cases and timely referral for taking care of infected people.

References

1. N van Doremalen, et al. Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. The New England Journal of Medicine. DOI: 10.1056/NEJMc2004973 (2020).
2. How does novel coronavirus (COVID-19) spread and how can I stop myself from getting it? Available at https://www.health.qld.gov.au/news-events/news/novel-coronavirus-covid-1....
3. As coronavirus spreads, many questions and some answers. Available at https://www.health.harvard.edu/diseases-and-conditions/coronavirus-resou... (March 24, 2020)
4. Kresge N, DodgeS. Lockdown’s success in China offers hope for world’s virus fight. Available at https://economictimes.indiatimes.com/news/international/world-news/lockd... (March 25, 2020).

Competing interests: No competing interests

25 March 2020
Dr.Mongjam Meghachandra Singh
Director-Professor
Dr.Reeta Devi, Assistant Professor
Department of Community Medicine, Maulana Azad Medical College, New Delhi; and School of Health Sciences, Indira Gandhi National Open University, New Delhi (India)
Department of Community Medicine, Maulana Azad Medical College, New Delhi; and School of Health Sciences, Indira Gandhi National Open University, New Delhi (India)