Anthony Fauci

More contagious than other variants, and maybe more likely to cause severe disease, Delta is spreading so fast in the U.S. it could cause another surge this summer or fall, according to new research.

"If I had grandchildren, I would certainly recommend they get vaccinated," President Biden's chief medical adviser said. COVID-19 vaccines for younger children are being tested in clinical trials now.

Cases are up in some states, but the Biden administration's chief medical adviser says that "hopefully ... the vaccine is going to win this one." He urges continued mask-wearing and other measures.

"This is a national emergency. Four hundred thousand people have died. Everything is on the table across the whole supply chain," said Jeffrey Zients, the White House COVID-19 response coordinator.

The U.S. hit more than 4,000 deaths on Jan. 7, which also saw 274,703 new infections, according to Johns Hopkins University. The U.S. continues to lead the world in both cases and deaths.

More than 91,000 people were hospitalized with the coronavirus on Saturday — over 6,000 of them on ventilators. With the holiday season fast approaching, health experts fear the worst is yet to come.

Health officials have warned Americans to forgo the traditional holiday travel as cases of the coronavirus continue to surge across the country.

Dr. Anthony Fauci tells NPR that strong testing results for both Moderna and Pfizer vaccines are "a very, very important advance" in trying to stop the coronavirus outbreak.

Animal and human trials are promising, Dr. Anthony Fauci tells lawmakers Friday, and the government is preparing for widespread distribution once a vaccine is shown to be safe and effective.