Jan. 29 (UPI) -- During a briefing Friday of President Joe Biden's COVID-19 Response Team, Dr. Anthony Fauci said the emergence of Brazilian, British and South African variants of the coronavirus is a "wake up call" that mass immunization programs should proceed as quickly as possible.
Fauci, the director of the National Institute of Allergy and Infectious Diseases, made the remarks during the response team's update late Friday morning.
"This is a wake up call to all of us that as the virus uses its devices to evade immunological pressure, we will continue to see the evolution of mutants," Fauci said, adding that vaccines would have to be "nimble" to adjust to fight mutated forms of the virus.
"The virus has a playing field to mutate. If you stop that replication, viruses can't mutate if they can't replicate."
Johnson & Johnson's late-stage clinical trials showed its vaccine is 66% effective. The figure is lower than the effectiveness of vaccines from Pfizer and Moderna, but Johnson & Johnson's was also tested against the South Africa variant.
The response team also acknowledged the first official U.S. cases of the variant that originated in South Africa and said schools nationwide would be safe to reopen if proper protocols are followed.
Centers For Disease Control and Prevention Director Rochelle Walensky said the United States is still experiencing an "extremely high" number of COVID-19 cases.
"We continue to have four times as many cases as we had over the summer," she said.
Walensky said one case of the Brazilian P1 variant was reported in Minnesota and more than 300 cases of the British mutation have so far been reported nationwide.
"We know that viruses mutate in a way that's advantageous to the virus," she said, asking Americans to be "steadfast" in a commitment to wearing masks and socially distancing.
"Now is not the time to travel," she said.
Walensky added that schools from kindergarten through 12th grade should be "the last settings to close after all other mitigations have been employed."
She said data suggest that school settings "do not result in rapid spread of COVID-19" when guidelines for masking, decreasing density and proper ventilation are followed.