Differing strains of the coronavirus continue to appear around the world and a new COVID-19 variant, the so-called "Delta" variant, has health experts concerned. The variant, otherwise known as B.1617 ...

"As these viruses continue to evolve, public health officials watch carefully to see whether new strains will be more easily ...

A newer COVID variant called XFG is currently fueling cases of the virus across the country. Nicknamed “Stratus,” this variant first took hold over the summer and now makes up nearly 70% of COVID-19 ...

In fall 2025, rumors spread that the strain of the virus in circulation that causes COVID-19 had "very different signs" compared to other strains of the virus. Referring to it as "COVID-25," people ...

The timing of symptom onset depends on lots of factors, including the amount of virus to which someone was exposed, Hotez says. Their level of pre-existing immunity may also affect the likelihood or ...