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How long is the coronavirus infectious?

Text updated on 2020-05-20


We don't know exactly, and it depends on the surface.

Coronavirus stability:SARS-CoV-2 coronavirus RNA could be detected on various surfaces for several days up to a week after they had been soiled, especially on plastics, metals, and masks. However, the likelihood that these viral particles could infect another person was not measured. It is therefore difficult, at present, to know how long the virus remains infectious on various surfaces. Most published studies have simply measured the presence of the virus' RNA but not its actual virulence. The available data on the time the virus remains detectable can therefore give an idea of the duration of maximum infectivity.

Virulence: During the infectious period, an infected person will touch certain surfaces (door handles, coffee machine buttons, elevators, shopping cart bars, public transport ramps, etc.) which will then be touched by dozens of other people. The number of people infected by an infected person varies greatly from person to person, and increases with population density. It has been estimated that one infected person typically infects a total of 2-6 people. Not all people who touch contaminated surfaces will become infected, especially if they apply strict hygiene rules themselves.

Evaluation of coronavirus stability in the laboratory or hospital from large quantities of virus :

paper/cardboard ~24h

copper ~4h

cotton fabric ~1 day

steel ~4 days

plastic ~ 3-7 days depending on studies

ceramic glass ~5 days

surgical mask ~7 days

After 5 min in bleach, or 70% ethanol, or soap, the virus is inactivated.

Warning: these guide values are given at room temperature and indoor temperature - they may vary under other conditions of temperature, lighting, and humidity.

In particular, under summer solstice conditions in temperate regions, sunlight illumination has a significant virus inactivation effect on non-porous materials. One hour of illumination of SARS-CoV-2 suspended in simulated and dried saliva is sufficient to inactivate virus particles.


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Sources

Measurement of the stability of the virus under different environmental conditions.

Chin, A., Chu, J., Perera, M., Hui, K., Yen, H. L., Chan, M., ... & Poon, L. (2020). Stability of SARS-CoV-2 in different environmental conditions.

Stability and methods for inactivation of coronaviruses.

Kampf et al, J Hosp Infect. 2020 Mar 104(3):246-251. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.

Covid-19 and SARS viruses persist similarly on different media.

Van Doremalen et al, N Engl J Med 2020; 382:1564-1567. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1.

Stability measurements for the SARS-CoV-1 agent.

Duan, S. M., Zhao, X. S., Wen, R. F., Huang, J. J., Pi, G. H., Zhang, S. X., ... & Dong, X. P. (2003). Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation. Biomedical and environmental sciences: BES, 16(3), 246-255.

Synthesis of information known at the end of March 2020 on SARS-CoV-2.

Bar-On, Y. M., Flamholz, A., Phillips, R., & Milo, R. (2020). SARS-CoV-2 (COVID-19) by the numbers. Elife, 9, e57309.

A study shows that simulated sunlight rapidly inactivates the SARS-CoV-2 coronavirus suspended in saliva or culture media and then dried on stainless steel. When exposed to type B UV corresponding to sunlight at a latitude of 40°N at sea level on clear days, ninety percent of the infectious virus was inactivated after 7 minutes in saliva at the summer solstice and after 14 minutes at the winter solstice. These data indicate that natural sunlight can be effective as a disinfectant for contaminated non-porous materials.

Ratnesar-Shumate, S., Williams, G., Green, B., Krause, M., Holland, B., Wood, S., .... Dabisch, P. (2020). Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces. The Journal of Infectious Diseases.

Further reading

Can a person without symptoms infect others?