What to know about COVID symptoms, testing and incubation as the new "razor blade throat" Nimbus variant has caused a summer 2025 spike.

The incubation period for COVID-19—the time between when SARS-CoV-2 first infects a person and when resulting COVID-19 symptoms first appear—has gradually shortened as the pandemic has ...

A new study suggests that with the evolution of mutant strains, the mean incubation period of COVID-19 decreased gradually from five days for cases caused by the Alpha variant to 3.42 days for the ...

Incubation period data were obtained from a total of 513 individuals which included 255 Delta and 258 Omicron cases who reported onset of symptoms between 1 December 2021 and 2 January 2022.

As the U.S. experienced a surge of the omicron variant in the previous months, information emerged about the new strain, prompting guidance changes from the Centers for Disease Control and Prevention.

A small study by the Centers for Disease Control found that omicron’s incubation appears to be about a day shorter than delta’s.

Early studies indicate omicron may have a shorter incubation period than prior coronavirus variants, but does that affect how long someone is contagious with the virus?

Early studies indicate omicron may have a shorter incubation period than prior coronavirus variants, but does that affect how long someone is contagious with the virus?