COVID-19 transmissions from fomites

Transmission of COVID-19 occurs in two major routes; respiratory droplet and contact transmissions. Droplet transmission occurs when a person is in close contact (within 2m) with someone who has respiratory symptoms (e.g., coughing or sneezing) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially infective respiratory droplets.

Contact transmission can occur through direct contact with infected people and indirect contact with surfaces in the immediate environment or with objects used on the infected person (e.g., home utensils, clothes, stethoscope, thermometer).  This objects which can harbor infectious agent and can get someone infected when contacted are called fomites. Transmission through fomites is common but somehow has been underrated to some people.

Virus present on fomites may be another source of infection if susceptible individuals touch these surfaces and then transfer infectious virus to mucous membranes in the mouth, eyes, or nose. It may be more likely to be a potential source of infection in settings where there is heavy viral contamination (e.g., in an infected individual's household or in health care settings).

Sadly, it is unknown how long the virus that cause COVID-19 (SARS-CoV-2) can persist on surfaces; other coronaviruses have been tested and may survive on inanimate surfaces for up to six to nine days without disinfection. In a study evaluating the survival of viruses dried on a plastic surface at room temperature, a specimen containing SARS-CoV (a virus closely related to SARS-CoV-2) had detectable infectivity at six but not nine days. However, in a systematic review of similar studies, various disinfectants (including ethanol at concentrations between 62 and 71%) inactivated a number of coronaviruses related to SARS-CoV-2 within one minute. Based on data concerning other coronaviruses, duration of viral persistence on surfaces also likely depends on the ambient temperature, relative humidity, and the size of the initial inoculum.

Prevention of transmissions from fomites.

1.       Clean your hands often. Wash your hands often with soap and water for at least 20 seconds especially after you have been in a public place, or after blowing your nose, coughing, or sneezing. If soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol. Cover all surfaces of your hands and rub them together until they feel dry.

2.       Avoid touching your eyes, nose, and mouth with unwashed hands.

3.       Except for health worker with personal protective equipment (PPE) avoid close contact with people who are sick. Stay home as much as possible. Put distance between yourself and other people to reduce risk for being in contact with fomites. Remember that some people without symptoms may be able to spread virus. Keeping distance from others is especially important for people who are at higher risk of getting very sick.

4.       Avoid touching surfaces with your unwashed bare hands. Remember, you can be asymptomatic but still infect others through fomites.

5.      Clean AND disinfect frequently touched surfaces daily. This includes tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks. If surfaces are dirty, clean them. Use detergent or soap and water prior to disinfection. Then, use a household disinfectant.