August 15, 2020

Novel coronavirus

In the beginning of the pandemic, SARS-CoV-2, the virus that causes COVID-19, was called a “novel virus”. They weren’t kidding. One of the medical assistants at work wondered what novel meant. Back then, I explained that it was a newly recognized virus that had never infected humans before. Now, I think that this virus is novel in so many more ways than just that. The disease and symptoms it causes are unique. We have not ever really seen anything like it before, even the coronaviruses that caused the SARS and the MERS outbreaks. SARS (Severe Acute Respiratory Syndrome, caused by SARS-CoV, occurred in 2002-2004 with fever, muscle aches, cough, and severe respiratory distress in some. Only about 8500 cases occurred with a fatality rate of 11%. It was spread through mucous membrane contact with respiratory droplets and fomites (droplets that have landed on surfaces and transferred via touching the mouth, nose, or eyes with unwashed hands). That is why hand washing was emphasized early in the SARS-CoV2 epidemic. SARS was contained with isolation and droplet precautions with personal protective equipment like N-95 masks, which protected the health care workers from exposure.

MERS, the Middle Eastern Respiratory Syndrome, was an outbreak in 2012-2013 caused by MERS-CoV virus. MERS had similar symptoms to SARS, causing severe pneumonia and respiratory disease. MERS-CoV was not easy to to transmit and only 2500 cases with about 860 deaths have occurred since it was identified. In both these diseases, isolation, masking, contact tracing were all used to contain the spread.

That is why when this new, novel coronavirus appeared, there was hope that isolation and hand washing to avoid fomites would be enough to contain the spread. The prior diseases were not considered to be so highly infectious and social distancing and hand washing would be enough, based on what we knew about the prior coronavirus diseases. Best guesses were made based on initial reports of the first infections and prior knowledge.

It was not thought to be through airborne transmission. Airborne transmission is through small particles, or aerosols that are less than 5 microns, that float in the air, distinct from respiratory droplets that fall to the ground. Measles is airborne which is why we hear all about exposures when someone later diagnosed with measles passes through an area, such as a store or airport. The transmission is so much easier.

For many months the evidence has pointed towards airborne transmission of SARS-CoV-2, not just from respiratory droplets and fomites. This is the big reason being outdoors is safer than indoors. It may be why Texas, Florida, Arizona, and Georgia are hotspots if more people are indoors using air conditioning due to the heat. It is why ventilation should be considered when re-opening schools. Helpful links can help you figure out your own risks in specific situations. It may be why doctors, nurses, and other hospital workers are at higher risk for infection, as well as nursing home residents and people living in Frat houses. More evidence points to this mode of transmission and the CDC is now recognizing it exists. This makes mask wearing much more compelling.

But COVID-19 is novel in so many other ways that are unexpected. Some of these are the idea that the risks of severe disease and death increase greatly with age; that it infects so much more than the lungs and throat; it can cause severe blood clots which harm the kidneys, the lungs, the brain, and other organs; that some people with no risk factors seem to develop a hyper-immune response that causes more damage than the virus itself. It also presents in ways that doctors have never seen before: a patient with dangerously low oxygen can be talking normally and unaware of how ill they really are, they don’t have the usual symptoms of rapid breathing and shortness of breath. They have learned people can lie on their bellies and their oxygen improves. And then there are the sequela, the long term after effects. We are still learning about those. We don’t yet know what they mean and if they will improve.

So yes, this is a novel virus and the end of that novel is not yet written.

Wash your hands, cover your nose (more important than ever to wear a mask), keep safe six, outdoors.

And finally, my caveat is that this is my experience and my opinions, which are subject to change as more information is available, and not related to the organization I work for. Thanks for reading.

https://www.nationalgeographic.com/science/2020/08/what-airborne-coronavirus-means-and-how-to-protect-yourself-cvd/#close

https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome

https://en.wikipedia.org/wiki/Middle_East_respiratory_syndrome–related_coronavirus

https://en.wikipedia.org/wiki/Airborne_transmission

https://www.nationalgeographic.com/science/2020/08/what-airborne-coronavirus-means-and-how-to-protect-yourself-cvd/#close

https://www.pbs.org/newshour/health/analysis-ventilation-should-be-part-of-the-conversation-on-school-reopening-why-isnt-it

https://www.nationalgeographic.com/science/2020/08/how-to-measure-risk-airborne-coronavirus-your-office-classroom-bus-ride-cvd/

https://www.nytimes.com/2020/08/11/health/coronavirus-aerosols-indoors.html