Asymptomatic Covid and Genetics

Covid is surging in certain areas of the United States but the good news is that only about 5% of patients that are sick enough to need hospitalization are needing intensive care. That is a very small number. But you are more likely to get Covid now than you were earlier this Summer. And the majority of cases are not reported so data comes from wastewater surveillance testing. OK that's the current landscape. Lets talk about people who have asymptomatic Covid-19.

A new study published in Nature shows us that some people have a genetic variant that gives them T-cell immunity from previous bouts of the common cold! These genes encode molecules that are essential to the immune response. By looking at 30,000 people who were potential bone marrow donors, they were able to sequence their specific genes and track their response to the Covid virus.

They found that in the small percentage of people who had Covid but no symptoms, a small allele (gene variant) known as HLA-B*15:01 stood out. People with the variant were twice as likely to have no symptoms. People with two variants (from both parents) were 8X more likely to have no symptoms than people without it. Even before the pandemic began, these people had T-cells that were effective against Covid-19.

People with HLA-B*15:01 who were previously exposed to the cold virus developed T-cells that rapidly killed Covid. This allele was found more in European ancestry. There may be other variants that have not yet been found in other ancestries and more research is needed to see.

There is not just one factor-genetic or otherwise-that determines outcomes for people with Covid. There are a number of non-genetic influences that we know...older age, obesity, smoking, vitamin d deficiency, immune suppressed, and just general poor health. It's only fair to mention that lack of access to healthy nutrition and healthcare are risk factors also. Americans living in poorer counties died during the pandemic at almost twice the rate of those in rich counties.

From 2019-2020 (before the epidemic), median income of lower-income households decreased by 3.0% and middle income households fell by 2.1%.