Dr. Anthony Fauci said the recent Johnson & Johnson vaccine study, as well as one conducted by Novavax, are proof that coronavirus mutations that lead to different lineage "do have clinical consequences," and should serve as a "wakeup call" that the vaccines currently in development may need tweaks to combat new strains.

Fauci’s comments came hours after J&J released a study indicating that it’s one-shot vaccine proved to be 72% effective in the U.S. against moderate-to-severe coronavirus, but fell to 66% in Latin America and 57% in South Africa, where a "troublesome" variant has taken over.

"What we now know from this study, namely the J&J and the Novavax study, that antigenic variation, I.E. mutations that lead to different lineage, do have clinical consequences because as you can see, even though the long-range effect in the sense of severe disease is still handled reasonably well by the vaccines, this is a wakeup call to all of us that we will be dealing, as the virus uses its devices to evade pressure, particularly immunological pressure, that we will continue to see the evolution of mutants," he said during Friday’s White House coronavirus briefing. 

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"So that means that we as a government, the companies, all of us that are in this together, will have to be nimble to be able to readily adjust, readily make versions of the vaccine that actually are specifically directed toward whatever mutation is actually prevalent at any given time," he said.

The so-called U.K. variant, identified as B.1.1.7, has already been detected in over 300 cases in the U.S., while the P.1. mutation, believed to have originated from Brazil, has been confirmed in a Minnesota case. The South African variant, which health officials have previously described as worrisome, was detected in two cases in South Carolina earlier this week. The cases do not have epidemiologic relation, Dr. Rochelle Walensky, the CDC director, said in the call on Friday.

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Walensky and Fauci said increased genomic surveillance and sample testing will strengthen the nation’s ability to combat the mutations, and potentially avoid scenarios that could see one dominate the other. Fauci said the best defense, in addition to continuing public health measures, is to vaccinate as many people as possible to keep transmissibility low.

"This all tells us that it is an incentive to do what we've been saying all along -- to vaccinate as many people as we can as quicly as we possibly can," he said. "Mutations occur because the virus has a so to speak, playing field to mutate. If you stop that and stop the replication the virus cannot mutate." 

He said the variant gaining stronghold in Los Angeles and California is a result of the amount of virus in the community.

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"You can be certain as long as there is a lot of virus in the community there will be the evolution of mutants, that’s what viruses do, particularly RNA viruses," he said. "You’re giving the virus an opportunity to adapt."