A Genetic Test for SARS-CoV-2 Infection Risk?

The current COVID-19 pandemic has spread to nearly every country. At the time of this writing, over 1,000,000 people have been infected by the SARS-CoV-2 virus at the center of the pandemic. The damage to the global health and economy (including the impact of coronavirus on unemployment) is unprecedented. 

However, nearly 95% of cases only show mild symptoms and most of these people recover. For the other 5%, symptoms can lead to severe respiratory distress, hospitalization, and death. There are many, many reasons that some people are more susceptible to the virus than others. Poor lung health, bad circulation, and lowered immune function have all been fingered as potential culprits for increased viral susceptibility. 

However, researchers at 23andMe also believe that some answers may be found in the genome. Your DNA codes for tens of thousands of different proteins, all of which serve a different function in your body. Some of these proteins may help protect you against the virus!

In fact, genome-wide association studies have identified genetic variants that have played a role in past pandemics.

The Last SARS epidemic: Genes that Increase Your Risk

With Nebula Genomics, a whole-genome sequencing company, you can easily see how your genes may have played a role in the last SARS epidemic.

SARS – which stands for severe acute respiratory syndrome – is simply a condition caused when a virus infects your lung and respiratory tissues. Viruses use your cells to reproduce. They infect a single cell, use that cell’s machinery to produce a huge number of new virus particles, then explode out of the cell to spread.

These new virus particles spread to other healthy lung cells, infect them, and the cycle continues. If your immune system doesn’t react fast enough (or if your lungs are damaged already), the virus quickly destroys much of the healthy tissue within your cells. This leads to an inability to breathe – an essential function for life. 

In order to predict how your body may have reacted to the last SARS epidemic, researchers searched thousands of genetic variants to see which ones led to an increased risk of death and hospitalization. They found that much of the susceptibility to the last viral epidemic was in no small part caused by mutations in anti-viral proteins that your immune system uses. People with mutations in these genes had a statistically higher chance of experiencing extreme symptoms and complications due to viral infection. 

But, this is not the SARS epidemic. It’s the COVID-19 Pandemic.

The SARS epidemic in 2003 affected only 26 countries, and was contained in a matter of months. The original SARS-CoV virus was not nearly as infective or contagious, and was much more easily contained. 

This virus, SARS-CoV-2, may have a similar name but is almost nothing like the previous virus. While the two are from the same family of coronaviruses, they are as distantly related as a human and an orangutan. 

At a biochemical level, this means that the SARS-CoV-2 virus may use entirely different proteins and mechanisms in order to access and reproduce within human cells. Unfortunately, this means that previous genome-wide association studies like the one mentioned above have little-to-no value in predicting your risk in the COVID-19 pandemic.

That’s why 23andMe is launching a new study to find genetic risk factors for this new CoV-2 virus. 

How Will This Work? And When Can I Get a COVID-19 Genetic Test?

Current 23andMe customers will find a new survey on their 23andMe dashboard. This survey asks you where you live, if you have been tested for CoV-2, and how severe the disease was if you caught it.

With over 10 million customers (80% who have consented to research), 23andMe has one of the largest genetic databases on Earth. Using survey results, 23andMe seeks to correlate various genetic mutations to more severe outcomes such as hospitalization and severe respiratory distress.

However, the study is also looking at environmental factors, preexisting conditions, and a number of other factors to ensure that correlations they find are not false-positives. In other words, 23andMe is looking at as many factors as possible (including many non-genetic factors) to ensure that they find any genes that increase your susceptibility to the COVID-19 pandemic. 

If you want to help with the study and find out what genetic variants you might carry that can contribute to your risk, simply order a 23andMe DNA test kit. In addition to hundreds of other surveys – you can take the COVID-19 survey and help scientists discover the genetic basis of SARS-CoV-2 risk factors!

Genetic Testing DOES NOT tell the Whole Story

Like all genetic health predisposition tests, the findings of this study will simply be a statistical analysis of your risk. And, unfortunately, there are many genetic and environmental factors that 23andMe will not test for that could ultimately increase your risk. 

Part of the reason 23andMe is likely to miss many mutations that increase risk is that they do not search your entire genome. Instead, 23andMe uses SNP (single-nucleotide polymorphism) testing. Having searched the genomes of millions of people, 23andMe has identified some very common variants within the genome that have likely been passed down in families for a long time.

Unlike whole-genome sequencing, this does not measure every single nucleotide in your DNA. In fact, it only measures about 700 thousand out of 6 billion!

You could easily have mutations in other parts of your DNA that lead to variants within the proteins your body creates. These proteins, some of which confer resistance to the virus, can easily lose function due to many mutations that 23andMe will never be able to find. So, even if the 23andMe study finds you have a decreased risk of severe infection, you still need to be careful. 

Continue Social Distancing to Help Others

While this is an extremely cool use of 23andMe’s massive genetic database, it is not a replacement for social distancing. This is extremely important to understand.

Social distancing, stay-at-home orders, and other forms of distancing yourself from the population are not just for your benefit. Even if you find you have a decreased risk (genetically) of having bad symptoms – you can still get the virus.

If you get the virus, even if your symptoms are mild, you can still spread the virus and shed virus particles into the environment. So, you could easily infect a highly-susceptible person and cause them to be hospitalized – or worse.

Social distancing, as a community practice, is designed to lower the rate of infection. If everyone gets infected around the same time, hospitals will be greatly overwhelmed. New York is seeing the effects of mass infection now. Hospitals are overwhelmed, doctors do not have enough protective equipment, and there is a severe shortage of ventilators for people who need medical intervention.

Social distancing, though it is enormously frustrating and is currently wreaking havoc on the economy, is the only method we have of “flattening the curve” – or lowering the rate of infection so that people with severe cases can get the medical care they need. 

The more we do now to distance ourselves from others and reduce the spread of the virus, the more lives we save.

Be safe out there, and take care of each other!

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