Melissa Healy

British scientists have bolstered their case that the new coronavirus variant spreads more easily than its predecessors. It could be worse in the U.S., they warn.

A poor showing by a COVID-19 vaccine from AstraZeneca and Oxford University prompted South African health officials to shelve plans to inoculate health workers.

Coronavirus variant first seen in L.A. now accounts for about half of Southern California’s infections and has spread to 18 states and six countries.

Scientists fear “nightmare scenario” where a patient is infected by two different coronavirus strains that swap mutations and become more dangerous.

Two COVID-19 vaccines have now been linked to a risk of developing blood clots. Scientists don’t know whether the vaccines are to blame.

We explain what vaccine passports are, how they work, where they’ve been implemented, and why some people object to them.

We look at the science behind the need for COVID-19 booster shots.

A growing contingent of medical experts is questioning the conventional wisdom that healthy children should get COVID-19 shots as soon as possible.

With immunity waning and the Omicron variant looming, many scientists are saying the definition of ‘fully vaccinated’ should include a booster shot.

Authorities did not say what prompted the shooting Saturday night.