Dr. Anthony Fauci said Friday that new variants of the coronavirus that were initially found in the United Kingdom, South Africa and Brazil — and have since been — are expected to persist and eventually outnumber cases of the earlier strain of the virus.
"We will continue to see the evolution of mutants," Fauci, the nation's leading infectious diseases expert, said at a news briefing Friday.
Thehas now been found in 29 U.S. states, according to Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention. Highly contagious variants first identified in and Brazil have also been found stateside.
Fauci said vaccinating "as many people as we can, as quickly as we can," is the best defense against new variants. "The virus has a playing field to mutate," he said, explaining that the virus cannot mutate if it is not given the chance to replicate.
"The virus will continue to mutate and will mutate for its own selective advantage," he said. If COVID-19 is prevalent in a community, it is only a matter of time before the virus mutates as it is given ample "opportunity to adapt."
A newly identified strain of the coronavirus prevalent in Southern California could be behind the drastic spike in cases in the region. A study released on January 18 found that more than a third of recent COVID-19 patients at Cedars-Sinai Medical Center in Los Angeles were infected with the strain, according to a release summarizing its findings.
"The fact is that when you have a virus that has ability to transmit more efficiently than the wild type in the community, sooner or later by pure viral dynamics itself it will become more dominant than the wild type," Fauci said.
Variants are likely affecting other U.S. cities, according to Fauci, butto identify them all. Andy Slavitt, senior advisor to the White House COVID-19 response team, again called on Congress to pass President Biden's so the federal government can scale up sequencing along with other strategies to quell the pandemic.
"We should be treating every case as if it's a variant," Walensky said, noting that "by the time someone has symptoms, gets a test, has a positive result, and we get the sequence, our opportunity for doing real case control and contact tracing is largely gone."
Fauci said federal officials are concerned about a number of variants, in particular the mutation first identified in the U.K., which has been show to transmit more easily than the original COVID-19 strain. That feature, he said, means its dominance is inevitable. Current projections show that the variant "will become more dominant than the wild type," by March or April, he said.
"The fundamental principle of getting people vaccinated as quickly and as efficiently as you possibly can will always be the best way to prevent the further evolution of any mutant. Because when you do that you prevent replication, and replication is essential for mutation."
In addition to vaccinating as many people as possible with the current vaccines from Pfizer and Moderna, Fauci said federal health officials and companies developing vaccines will need to remain "nimble" in order to produce versions aimed at variants.
"We as a government, the companies, all of us that are in this together, will have to be nimble to adjust readily to make versions of the vaccine that actually are specifically directed towards whatever mutation is actually prevalent at any given time," he said.
There have been concerns in recent weeks that the vaccines could be less effective against some variants, the highly transmissible South Africa variant in particular.
U.S. biotech firm Novavax said Thursday that its two-shot COVID-19 vaccine showed an overall efficacy of 89.3% in a major Phase 3 clinical trial in Britain, andagainst a variant first identified there. Other results showed it offered less protection against the variant identified in South Africa, but both the company and an outside health expert were still optimistic about the level of protection provided against both new strains.
Fauci on Friday also discussed new results from, which showed 66% efficacy overall, and 72% in the United States. He acknowledged that the results could appear less impressive compared to Pfizer and Moderna's higher overall efficacy, but stressed that the vaccine has other advantages, namely its impact on severe disease and the ease of delivering its single dose.
"In the United States, in South Africa and in Brazil, the overall efficacy for severe disease was 85%. And in fact in the study including the South African isolate, there was essentially no hospitalizations or deaths in the vaccine group, whereas in the placebo group there were," Fauci said. "So this really tells us that we have now a value-added additional vaccine candidate."
"This has important potential and real implications domestically and globally because … this is awhich you start to see efficacy anywhere from 7 to 10 days following the first and only shot," Fauci said. It can be stored in a regular refrigerator, is inexpensive, and the company is "capable of making doses in the numbers of billions."
The briefing came a day after Fauci said President Joe Biden's push to reopen most schools within 100 days "may not happen." In an interview with the American Federation of Teachers and the National Education Association on Thursday, Fauci expressed caution over Mr. Biden's goal.
"That may not happen because there may be mitigating circumstances," Fauci said.
Meanwhile, White House press secretary Jen Psaki on Thursday reiterated Mr. Biden's support for a $1.9 trillion COVID-19 relief package to be passed in Congress, and said that the White House was not interested in breaking the bill up into smaller portions. Some Republicans have balked at the price tag for the bill, and it is unclear whether it will be able to garner any GOP votes.
Psaki said Mr. Biden had reached out to both Republican and Democratic members of Congress to discuss coronavirus relief.