Think You Never Got Covid-19? Thank Your Genes

livemint.com:

You might know a Covid-19 super-dodger who was infected with the virus but didn’t get sick. Their luck could be written in their genes. A DNA variation that affects the immune system can boost a person’s odds of avoiding Covid-19 symptoms, a study found.

The work, published Wednesday in the journal Nature, helps explain why some people infected with the virus that causes Covid-19 don’t fall ill. The T cells of some people with the variation can find and kill the virus without having seen it before, researchers said. That is because the part of the virus their T cells home in on is similar enough to common coronaviruses they have already encountered.

“There are people out there that have got strong prior immunity from their common coronavirus exposures," said Danny Altmann, a professor of immunology at Imperial College London, who wasn’t involved in the study. The work could help researchers design better vaccines, Altmann said. People with a copy of the genetic variation were more than twice as likely to avoid symptoms than people without it, the researchers found.

For people with two copies, the chance of avoiding symptoms increased more than eightfold. Weekly reported Covid-19 deaths and hospitalizations in the U.S. are at record lows, federal data show.

Concentrations of the virus detected in wastewater have ticked up recently from a low base. Health officials and hospitals have pulled back on reporting and surveillance. Yet researchers are still exploring mysteries about the virus including why some people get infected and transmit it without getting sick.