The delta variant is fueling the COVID-19 surge in the United States, but experts warn that a more dangerous variant could emerge if more Americans don't get vaccinated. Delta is the most recent of ...

There is a risk that the highly transmissible delta variant first identified in India could become the dominant strain in the U.S. if vaccination rates lag, Anthony Fauci, MD, director of the National ...

The proportion was estimated at approximately 3% in late May. A highly contagious variant of the novel coronavirus that was initially identified in India now accounts for about 58% of all COVID-19 ...

The U.S. has surpassed 20,000 new COVID-19 cases for the fourth day in a row as the highly contagious delta variant persists in its track in being the most common form of the coronavirus in the ...

OBJECTIVESTo evaluate the effectiveness of the mRNA-1273 vaccine against SARS-CoV-2 variants and assess its effectiveness against the delta variant by time since vaccination. DESIGNTest negative ...