< 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.

Mail can be left to stand for a few hours, preferably in a warm place, before being opened, and one day for parcels. If you cannot wait and you think there is a risk of contamination, you should take care that the outside of the envelope does not come into contact with the contents, then put the envelope directly into a closed bin, and wash your hands afterwards.

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?