Danny Altmann, professor of immunology at Imperial College London, said it was not a "safe bet" to rely on immunity to Covid-19 as a strategy for coping with the pandemic.
"I can't make an accurate prediction but it's going to be very disturbing," Fauci told senators at a hearing held by the Senate Health, Education, Labor and Pensions Committee.
The number of people hospitalized with Covid-19 was growing by 5% or more in 23 states, based on a seven-day moving average, according to the Covid Tracking Project.
Regeneron Pharmaceuticals said on Monday it began late-stage clinical trials to assess the effectiveness of its antibody cocktail in preventing and treating Covid-19.
The Supreme Court struck down a Louisiana law that would have required abortion providers to have admitting privileges to a nearby hospital. The law was nearly identical to one in Texas that the Supreme Court ruled against in 2016. These laws are part of a strategy by anti-abortion activists to limit access to abortion and eventually overturn Roe v. Wade.
Even as Florida continues to report record case numbers, Gov. Ron DeSantis said the state will not halt its re-opening and refuses to order a statewide mask mandate to curb the spread of the virus.
The U.S. Food and Drug Administration has granted emergency use authorization (EUA) to Becton Dickinson for a Covid-19 antigen test that can be administered at the point of care and produce results within 15 minutes, the company said on Monday.