Whether omicron coronavirus variants cause long COVID symptoms as often—and as severe—as previous variants is a matter of heated study.

The engineered protein vaccine was highly effective in a clinical trial but faced a long delay for authorization.

The update aims to help the public better protect themselves and understand their risk.

New studies offer evidence that an unexpected virus plays a role—but it needs a helper.

Antibody levels decrease substantially within three months after a booster, according to new clinical trial data.

The pandemic also disrupted medical care and had an indirect effect on other causes of death.

Two drugs widely used to treat certain autoimmune diseases substantially improved clinical status and reduced deaths.

After a long wait, the FDA authorizes Pfizer and Moderna vaccines for children as young as 6 months old.

The virus can be transmitted via respiratory droplets at close range, but it does not spread through the air over longer distances.