APOORVA MANDAVILLI

A third dose would enhance immunity to the coronavirus, the agency said. But hesitancy is high, and less than one-third of children in this age...

Scientists and federal health officials are debating plans to pair coronavirus and flu vaccinations in the fall.

The spread of the Omicron variant has given scientists an unsettling answer: repeatedly, sometimes within months.

But prior infection does not guarantee protection from the virus, officials said, and Americans should still get vaccinated and boosted.

Blood tests showed a sharp increase in the proportion of people — especially children and adolescents — in the United States who had antibodies indicating...

Studies linked to Cassava Sciences, once a stock market favorite, have been retracted or challenged by medical journals.

The new subvariants, both related to BA.2, may help explain rising infections in the region. They have been found in more than 30 states.

Scientists are exploring a theory suggesting that exposure to one respiratory virus helps the body fend off competing pathogens.

The vaccines shielded adolescents only against life-threatening Covid, not less severe illness, scientists reported. Still, hospitalizations remained rare in children, compared with adults.

Even before the war, the country struggled with epidemics of H.I.V., tuberculosis and hepatitis. The conflict threatens to undo decades of progress.