Surface Survival of SARS-CoV-2

Seriously, how long can this thing survive on surfaces?

In an earlier post, I referenced some preliminary research suggesting that SARS-CoV-2, the virus that causes COVID-19, can live in the air and on surfaces between several hours and several days. This work, originally released as a pre-print and recently finalized and published in the New England Journal of Medicine, found the virus is viable for up to 4 hours on copper, 24 hours on cardboard, 48 hours on stainless steel, 72 hours on plastics, and is also detectable in the air for 3 hours. 

A lot of posts present this information out of context and headlines can make it sound frightening, “SARS-CoV-2 Lives on Plastic for 72 Hours!!!” However, what’s more important is the amount of virus that’s still alive. It’s <0.1% of what the investigators started with. So, infection is theoretically possible but extremely unlikely at the levels they saw after a few days. 

Another important thing to mention lies in the experimental design of the aerosol component of the study. It has some caveats. They found that the virus can be detected in the air for 3 hours in the lab. However, in nature, respiratory droplets fall to the ground at a faster speed than the aerosols generated in their experiments. This is because the lab-generated aerosols are smaller (<5 μm) than what is produced from a cough or sneeze, so they remain in the air at face-height longer than the natural, heavier particles. It’s not a perfect comparison (though science rarely is, we just do our best). The size of these particles can affect how they move through the air and how they impact a surface. 

So, at the end of the day you’re more likely to become infected through the air if you’re next to an infected person versus a contaminated surface. Make sure you clean surfaces with disinfectant or soap – they work because they disturb the oily external layer of the virus keeping it from infecting your cells. 

The Novel Coronavirus – Key Terms

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The novel coronavirus, or SARS-CoV-2, is the virus responsible for the COVID-19 illness.

What is the novel coronavirus?

Okay, first things first, let’s start with a few key terms to clarify any mixed messages you may be receiving.

Coronavirus: The name given to a family of viruses that cause disease of varying severity in mammals and birds. Viruses from this family can be responsible for the common cold, but other members of this family have caused two large-scale pandemics in the past two decades, sudden acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Viruses are classified into families based on their structure and genetics, so it’s kind of like coronaviruses are the Mariners.

SARS-CoV-2 (sudden acute respiratory syndrome coronavirus-2 or the novel coronavirus): This is the specific name of the novel viral organism. If we continue our example from above, this would be a specific baseball player (Ichiro, Ken Griffey Jr, etc). It’s novel, or new, because this a virus that our immune systems have never seen before.

COVID-19: This is short for coronavirus disease 2019 and the name of the disease/illness caused by the novel coronavirus that originated in Wuhan, China in 2019.

Epidemic: A sudden increase in the number of cases of a disease above what is typically expected in a given area.

Pandemic: An epidemic that has widespread human infection in multiple countries across the globe.

Signs: Objective measurement to characterize an illness during a physical exam by a healthcare provider (e.g. temperature, respiratory rate, oxygen saturation).

Symptoms: Subjective evidence of an illness or abnormal process occurring in the body and reported by the patient (e.g. fatigue, nausea, anosmia, ageusia, myalgia).

Incubation Period: The time from when someone is infected to when symptoms develop. Based on existing evidence-based research, the incubation period of SARS-CoV-2 and other coronaviruses (e.g. MERS-CoV, SARS-CoV) ranges from 2–14 days. 50% of people will become ill 5 days after infection.

Infectious Period: The time when an infected person, who may not be showing symptoms, can transmit the virus to others. While it varies from person to person, it is typically ~ 7 days.

Molecular test — RT-PCR (Reverse transcription polymerase chain reaction): This is a molecular diagnostic test that identifies the presence of virus in the body through collection of nasopharyngeal, oropharyngeal, or other respiratory specimens by swabbing. The turn-around time for results varies greatly depending on the laboratory doing the test, but the current range is somewhere between 1 and 5 days.

Antibody Test — Serology: Blood test with a turn-around time of typically same day, but sometimes can take a couple of days. Serology is especially important because it may detect previous infections in people who had few or no symptoms.

Antigen test — Rapid: Rapid diagnostic test with a turn-around time of less than one hour. Antigen tests look for specific proteins on the surface of the virus and can diagnose an active infection.


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