COVID-19 vaccination was associated with a temporary average increase in menstrual cycle length of less than one day.

Biden may not have used the right word when he described the pandemic as “over,” but things are trending in the right direction.

Updated boosters could go to the “worried well” who have good insurance rather than to those at highest risk.

Higher levels of viral antigens in the blood correlated with more severe disease.

Updated Pfizer-BioNTech and Moderna bivalent boosters contain spike proteins from the original and BA.4 and BA.5 omicron variants.

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

An experimental vaccine produced an immune response to a range of different coronaviruses in mice and monkeys, including SARS-CoV-2.

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.

Using wastewater to track the emergence of new variants of concern could be faster and less expensive than clinical testing.