Nature-Had COVID? You’ll probably make antibodies for a lifetime-NEWS 26 May 2021 Correction 27 May 2021

 People who recover from mild COVID-19 have bone-marrow cells that can churn out antibodies for decades, although viral variants could dampen some of the protection they offer.

Antibodies — proteins that can recognize and help to inactivate viral particles — are a key immune defence. After a new infection, short-lived cells called plasmablasts are an early source of antibodies.

But these cells recede soon after a virus is cleared from the body, and other, longer-lasting cells make antibodies: memory B cells patrol the blood for reinfection, while BONE MARROW PLASMA CELLS (BMPCs) hide away in bones, trickling out antibodies for decades.

To identify the source of the antibodies, Ellebedy’s team collected memory B cells and bone marrow from a subset of participants. Seven months after developing symptoms, most of these participants still had memory B cells that recognized SARS-CoV-2. In 15 of the 18 bone-marrow samples, the scientists found ultra-low but detectable populations of BMPCs whose formation had been triggered by the individuals’ coronavirus infections 7–8 months before. Levels of these cells were stable in all five people who gave another bone-marrow sample several months later.