Dr. Anthony Fauci says the emergence and increasing spread of coronavirus mutations means vaccine makers must be ready to make new shots to stay ahead of the public health crisis.

The government’s top infectious disease expert spoke Friday during a White House coronavirus briefing.

“This is a wake-up call to all of us,” says Fauci, noting government scientists will be working to keep pace with virus mutations.

The nature of viruses is to change in ways that promote their spread, Fauci says. The evolution of mutant versions means scientists need to be “nimble” and ready to make tweaks to vaccines. So far, the mutants haven’t overwhelmed the protective power of vaccines.

Fauci says it is important to vaccinate people as quickly as possible to keep new mutations from developing.

 The head of the CDC says doctors and public health officials should approach each new case of the coronavirus as if it is a mutation.

“I do believe we should be treating every case as it if it’s a variant during this pandemic right now,” Dr. Rochelle Walensky said during a White House coronavirus briefing.

Two cases of the variant that originated in South Africa has been detected in South Carolina. There is concern if it continues to spread, it could become dominant in a few months.

Walensky says contact tracing efforts in the U.S. are not yet up to the task of containing the potential breakout of new mutations.

It was “concerning” the two South Carolina individuals who were diagnosed with the more virulent strain first identified in South Africa didn’t know each other or travel there, so the “presumption” is there’s “community spread of this strain,” Walensky said.

White House coronavirus adviser Andy Slavitt says Congress must move quickly to pass President Joe Biden’s coronavirus relief bill, which contains money to expand efforts to track and identify mutations.