One coronavirus infection wards off another — but only if it’s a similar variant

McKenzie Prillman in Nature:

Natural immunity induced by infection with SARS-CoV-2 provides a strong shield against reinfection by a pre-Omicron variant for 16 months or longer, according to a study1. This protection against catching the virus dwindles over time, but immunity triggered by previous infection also thwarts the development of severe COVID-19 symptoms — and this safeguard shows no signs of waning. The study1, which analyses cases in the entire population of Qatar, suggests that although the world will continue to be hit by waves of SARS-CoV-2 infection, future surges will not leave hospitals overcrowded with people with COVID-19. The research was posted on the medRxiv preprint server on 7 July. It has not yet been peer reviewed.

The study is “solid”, says Shane Crotty, an immunologist at the La Jolla Institute for Immunology in California. “The data make sense and are in line with multiple other studies and previous work by this group.”

More here.