< Hygiene
How long does the coronavirus remain infectious on the skin?
Text updated on 2021-05-03
The virus SARS-CoV-2 can survive for several hours on the skin. Although contact infections seem to be rare, it is important to wash your hands often and carefully.
The only study on the survival of coronavirus on human skin shows that the number of viruses is divided by one hundred in two hours and there are no more left after 9 hours. In this study, a drop of virus-containing mucus was placed on a round of abdominal skin, removed postmortem and kept alive on culture medium at 25°C. 99% of the deposited viruses had disappeared within 2 hours, but it took 8-10 hours for all the viruses to die. This skin model has been validated: the survival of an influenza virus is indeed the same on the hands of volunteers and on these skin rings. However, our skin's temperature is 33-35°C, whereas the study was done at 25°C. But the virus dies faster when it is warmer, so it probably persists less than 8 hours on a living person.
Another study was carried out on a fresh, shaved pig skin. At 37°C the number of SARS-Cov-2 viruses was divided by 100 in 4 hours, and undetectable in 8 hours. At 22°C the number was divided by 100 in 24 hours and undetectable in 3 days. These results confirm those of the previous study.
To avoid transmitting SARS-CoV-2 particles through the skin, one should not shake hands, touch the face and face of others, and should sneeze into one's elbow and use disposable tissues. Contamination through objects that have been contaminated by an infected person seems to be rare (see the question How is COVID-19 caught?). In any case, it is important to wash your hands regularly and carefully.
Sources
Study on pieces of human skin, taken postmortem, and described above.
Hirose, R., Ikegaya, H., Naito, Y., Watanabe, N., Yoshida, T., Bandou, R., ... & Nakaya, T. (2020). Survival of SARS-CoV-2 and influenza virus on the human skin: Importance of hand hygiene in COVID-19. Clinical Infectious Diseases.Study on pig skin, taken at the slaughterhouse, and described above.
Harbourt, D., Haddow, A., Piper, A., Bloomfield, H., Kearney, B., Gibson, K., & Minogue, T. (2020). Modeling the Stability of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on Skin, Currency, and Clothing. medRxiv.One study among others shows that the coronavirus dies much faster at 37°C than at 25°C. In this study, the coronavirus SARS-CoV-2 survived 3 to 5 days on a glass plate at 20-25°C. At 37°C the virus survives less than 24 hours.
Chan, K. H., Sridhar, S., Zhang, R. R., Chu, H., Fung, A. F., Chan, G., ... & Yuen, K. Y. (2020). Factors affecting stability and infectivity of SARS-CoV-2. Journal of Hospital Infection, 106(2), 226-231.Several studies have compared a group of people who were asked to wash their hands regularly with another group who did not change their habits. All show that handwashing reduces the risk of respiratory infection.
Rabie, T., & Curtis, V. (2006). Handwashing and risk of respiratory infections: a quantitative systematic review. Tropical medicine & international health, 11(3), 258-267.