< Decontamination

Can you contaminate yourself by opening your mail?

Text updated on 2020-05-31

It's unlikely to contaminate itself by opening its mail.

The SARS-CoV-2 coronavirus can survive on paper and cardboard for about a day, so the likelihood of being infected through letters and packages is low.

Plastic blisters should always be removed, discarded, and then washed hands thoroughly. Mail can be left to rest for a few hours, preferably in a warm place, before opening, and one day for packages. If you can't wait, make sure that the outside of the envelope does not come into contact with the contents, then put the envelope directly into a closed garbage can and wash your hands afterward.

For microwave oven decontamination, first make sure that the object does not contain plastic or metal, and add a glass filled with water to the microwave oven to inactivate the virus. Without water, the decontaminating effect of the microwave is lost. Studies show that a microwave run at 900-1250 W for 20 seconds can inactivate many types of viruses.

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The SARS-CoV-2 virus can survive on paper and cardboard for about a day.

van Doremalen, N., Bushmaker, T., Morris, D. H., Holbrook, M. G., Gamble, A., Williamson, B. N., ... & Lloyd-Smith, J. O. (2020). Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. New England Journal of Medicine.

A microwave oven can kill HCV and AIDS viruses present in a liquid.

Siddharta, A., Pfaender, S., Malassa, A., Doerrbecker, J., Engelmann, M., Nugraha, B., ... & Goffinet, C. (2016). Inactivation of HCV and HIV by microwave: a novel approach for prevention of virus transmission among people who inject drugs. Scientific reports, 6(1), 1-10.

The avian IBV coronavirus and other viruses can be inactivated in 5 seconds in a 900 W microwave oven. The avian influenza virus (AIV) is inactivated in 20 seconds, but not completely in 5 seconds.

G. Elhafi, C. J Naylor, C. E. Savage & R. C. Jones (2004) Microwave or autoclave treatments destroy the infectivity of infectious bronchitis virus and avian pneumovirus but allow detection by reverse transcriptase-polymerase chain reaction, Avian Pathology, 33:3, 303-306.

Microwaves can inactivate pathogens in the presence of water but are ineffective on dry objects.

Jeng, D. K., Kaczmarek, K. A., Woodworth, A. G., & Balasky, G. L. E. N. (1987). Mechanism of microwave sterilization in the dry state. Appl. approx. Microbiol, 53(9), 2133-2137.

This study compares different mask decontamination methods, including microwave and conventional ovens.

Heimbuch, B. K., Wallace, W. H., Kinney, K., Lumley, A. E., Wu, C. Y., Woo, M. H., & Wander, J. D. (2011). A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. American journal of infection control, 39(1), e1-e9.

Further reading

How do you wash your hands?

Is the SARS-CoV-2 coronavirus resistant to cold or heat?

Can the SARS-CoV-2 coronavirus be inactivated in a microwave oven?

How long is the coronavirus infectious?