Popular Science: “This week the U.S. Food and Drug Administration authorized a second booster dose of COVID-19 vaccines for older people and some immunocompromised people who received their first booster at least four months ago. Under the new guidance, the agency said, all adults 50 and older and individuals 12 and older who have received an organ transplant or have an equivalent level of immunocompromise may receive the additional booster of an mRNA vaccine.

“What data we have suggests that the more comorbidities that you have—the higher the risk that you are of having severe disease—the more benefit you will have from a second booster,” Li says. “I would urge people who are eligible–those who are older, those who are immunosuppressed—really to take advantage of this and to get the second booster when you can.”