This is part of a series of articles featuring responses by Elon University faculty members to questions about the novel coronavirus 2019 (COVID-19) submitted by Alamance County community members.
Has the COVID-19 virus mutated at all since it originated last year?
The virus that causes COVID-19 likely originated from bats, as nearly identical viruses have been isolated from bat caves numerous times over the past several decades. The virus apparently jumped species into a scaly anteater called a pangolin. From there it spread to humans who came into proximity with the pangolins in an open air market in the city of Wuhan, China.
Like most viruses, the COVID-19 virus has a relatively high mutation rate compared to animals and plants. However, it mutates slowly relative to other viruses. The COVID-19 virus accumulates about 25 mutations per year, which is approximately a quarter the rate of the influenza virus. This is good news for humans because it increases the chances a future vaccine will work over a relatively long period of time.
Does the virus affect our DNA if we get it?
There are many types of viruses, and some of them affect our DNA. One group of viruses that permanently affects the DNA of our cells is called retroviruses. This group of viruses includes HIV. Retroviruses contain a type of genetic material called RNA, which gets converted into DNA and then added to our genome as part of their life cycle. Because the virus is now part of our cell’s genome, the only way to destroy a retrovirus is to destroy the infected cell.
Another group of viruses that affects our DNA is called herpesviruses. This group of viruses includes the chicken pox virus. Herpesviruses place their DNA next to our genomes. The DNA can go undetected in our cells for years, which makes these viruses impossible to cure.
The virus that causes COVID-19 is not like these others. It is a type of coronavirus, which includes viruses that cause some common colds and other diseases. Like HIV, coronaviruses contain RNA, but unlike HIV, they lack the molecular machinery needed to convert RNA into DNA. Therefore after you recover from COVID-19, the genetic material of the virus does not persist in your cells and is entirely eliminated.
I’m really curious about what we know about this virus on a molecular level. I know the virus that causes COVID-19 is an RNA virus and has those spikes all around (crown appearance), but how does it infect humans?
If you have seen images of the COVID-19 virus, you know it looks like a ball with spikes sticking out. These “spikes” play a critical role in how infection works. Suppose you get COVID-19 virus on your hands, and then touch your face before washing your hands. The cells near your eyes, nose, and mouth are lined with special proteins called ACE2 receptors that stick to the spikes of COVID-19. This allows the virus to enter your cells.
After replicating a few times, eventually some viral particles are carried to the cells lining your lungs, where it is particularly good at replicating itself. The presence of the virus in your lungs is what causes the dry cough that many experience as a symptom.
How long should a quarantine last?
There are two ways to answer this question: How long should a quarantine last for an infected individual, and how long should a quarantine last for a community to rid itself of the virus? The terms “quarantine” and “social distancing” are often used interchangeably, but have slightly different meanings. A quarantine is the complete absence of physical contact with others, and can apply to individuals or occasionally to entire communities. Social distancing is a minimization of contact, and can be achieved by greatly reducing contact with others.
Individuals who believe they may have been exposed to the virus should isolate themselves for approximately two weeks. This provides time to determine if the person develops symptoms. People who develop symptoms are advised to remain isolated for eight days after their symptoms end.
Some cities have experimented with full scale community quarantines. Although community quarantines are highly effective at stopping the pandemic, stringent social distancing — when observed as universally as possible — can be an effective way to stop the spread of the virus while ensuring that basic needs and individual freedoms are preserved.
To minimize the amount of time needed for future rounds of social distancing, we must have widespread ability to test for the virus. In the absence of social distancing, even one infected person in a community is enough to start a new outbreak. An effective strategy will require a two-phased plan: First we will need to reduce the number of people who have the virus by enforcing very strict social distancing on a large scale for a few weeks. The more strict the social distancing, the less time it will need to be applied for in order for most of the infected people to get better. The less strict the social distancing, the longer it will need to last to reach the same levels of effectiveness.
Once tests are readily available, we can reduce social distancing by testing many people for COVID-19 and then tracking down all the contacts of any person who tests positive so they can be tested. This approach has been very effective in places like South Korea and Germany, but requires widespread accurate testing, large groups of workers to track down and test all the contacts of any person who tested positive, and adequate protective equipment for these workers to keep them from becoming sick or spreading the disease, such as masks, gowns, and gloves.
This second phase of quickly detecting and isolating any outbreaks of the virus to prevent it from spreading will be a critical requirement for us to re-open our societies while we wait for a vaccine. Otherwise, every time social distancing is lifted, the virus will begin spreading again.
Does social distancing exist on a spectrum?
The biggest risk of the COVID-19 pandemic for any community is that it overwhelms our ability to care for the sick. If our society did nothing to adapt to the new virus, then the number of infected people in our community would continue to double every few days for the next several weeks. This scenario would be catastrophic — several times worse than what recently happened in New York City. Alamance Regional Medical Center does not have enough doctors, beds, and ventilators to care for this large number of patients, and has no way of getting more of these resources in time. This is why it was so important we slowed down the spread of the disease through social distancing.
Different countries and populations are experimenting with different degrees of social distancing. Strict social distancing is most critical in environments with closely-packed, at-risk communities, such as retirement homes. At the same time, social distancing is more challenging for grocery store clerks, medical professionals, delivery people, and other essential workers.
Young healthy people might be tempted to think social distancing does not matter for them as the disease tends to be mild in younger people. The main problem is that these people might then pass on the disease to others, which further spreads the pandemic. Also, although most young people have only mild cases, some have gotten seriously ill.
Alfred Simkin is an assistant professor of biology at Elon University. Reach him at firstname.lastname@example.org.
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