How much protection do you currently have against COVID-19? The answer depends on so much: whether you’ve already had COVID-19 (and if so, how long ago); whether you’ve been vaccinated (and if so, how ...

The Biden administration next month will relaunch a program for every American to order free COVID-19 tests through the mail, officials said. Administration officials said during a briefing Friday ...

A newly developed blood test that measures a specific immune response in the body could help doctors gauge how much protection a person has against Covid-19, according to a new study. The test, which ...

As SARS-CoV-2 continues to evolve, knowing your immunity status—both from vaccines and from infections—will become increasingly important. COVID-19 antibodies are the best proxy for disease immunity.