CDC director warns that strains in hospitalized instances may reverse a decline

Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention.

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New, highly contagious variants of the coronavirus pose a “threat” to the United States and could reverse the recent decline in Covid-19 cases and hospital stays, the head of the Centers for Disease Control and Prevention warned on Monday.

The US reported a 7-day average of 119,900 new Covid-19 cases per day last week, a decrease of nearly 20% from the previous week but is still “dramatically higher” than the summer peak, CDC said -Director Dr. Rochelle Walensky told reporters during a White House press conference about Covid-19.

The nation also reported an average of 9,977 Covid-19 hospital stays per day last week, a decrease of at least 17% from the previous week, she said.

“The continued proliferation of variants remains a major problem and threat that could reverse the recent positive trends we are seeing,” said Walensky. “Please keep wearing a mask and stay 6 feet away from people you do not live with. Avoid travel, crowds, poorly ventilated rooms, and get vaccinated if you can,” she added.

U.S. health officials, including Dr. Anthony Fauci, have raised concerns about the Covid mutations that may be beyond the protection of the vaccines currently on the market. Moderna, Johnson & Johnson and Novavax have previously said that their vaccines may be less effective against B.1.351, the highly contagious strain in South Africa.

On Sunday, South African Health Minister Zweli Mkhize said the country would stop using AstraZeneca’s Covid-19 in its vaccination program after data showed it offered minimal protection against B.1.351, the nascent strain there. He said the government would wait for advice from scientists on how best to proceed after disappointing results from a trial conducted by the University of the Witwatersrand.

As of Sunday, the CDC had identified 690 cases of the B.1.1.7 variant, which were first identified in the UK, Walensky told reporters on Monday. The agency has identified six cases of the South African tribe as well as three cases of P.1, a variant first identified in travelers from Brazil.

Walensky said public health officials are working to find more cases of these variants, adding that federal and state officials have increased genome sequencing 10-fold in the past three weeks. “We expect to find more cases in the coming weeks,” she added.

The U.S. is always working to find out exactly how contagious and deadly the new strains are, said Fauci, the country’s leading infectious disease expert.

British Prime Minister Boris Johnson said last month that early data suggests the strain on the country could be more deadly. Fauci said Monday that there is currently no data to suggest the virus is mutating into a “less virulent” strain, meaning less harmful than the original virus.

The UK data “has yet to be confirmed,” added Fauci. “So far, however, there is no evidence that it is less virulent. Sometimes when viruses mutate in order to spread more efficiently they become less virulent, but we have no data to suggest that this actually happens.”

Meanwhile, Fauci has been pushing for people to be vaccinated as soon as possible, saying last week that the virus cannot mutate unless it can infect hosts and replicate.