My 6-year-old has been exposed to SARS-CoV-2 at least four times and never tested positive. Many people fall into that category. Researchers have theories about why they've been able to ward it off.
An analysis of blood from people who had received the Johnson & Johnson COVID-19 vaccine found a lower level of neutralizing antibodies against viral variants but a strong response involving T cells.
Using two different COVID-19 vaccines is a bit like giving the immune system two pictures of the virus, maybe one face-on and one in profile.
What if your body could corral an infection instead of eliminating it? Immunologists who see this sort of "disease tolerance" in plants wonder what role it might play in asymptomatic human infections.
Two new human studies back earlier hints that vaccines designed to prevent respiratory infections might also provide some protection against Alzheimer's disease.
A growing number of researchers think until there's an effective vaccine, the coronavirus will simply persist in the population, causing illness indefinitely. Better to squelch the spread instead.
As many firms and academic researchers vie for blood donations from survivors in hopes of isolating components for new treatments, one project is turning for help from 10,000 Orthodox Jewish women.
Scientists don't know whether people who have been exposed to the coronavirus will be immune for life, or if it can infect us again and again, like the common cold.
It's just a bit of genetic material wrapped in protein and fat. But the virus behind COVID-19 can wreak havoc deep inside human lungs when it triggers the immune system to go into overdrive.