Health and Science

CDC director says U.S. needs to curb Covid before it can mutate again and make the pandemic even worse

Key Points
  • The U.S. needs to rapidly deploy Covid-19 vaccines and ramp up its surveillance before highly contagious variants make the pandemic even worse, CDC Director Dr. Rochelle Walensky said.
  • The variant first found in the U.K. has proven to be highly transmissible and early data suggests it could be more deadly, Walensky said in a paper published Wednesday.
Dr. Rochelle Walensky, who has been selected to serve as director of the Centers for Disease Control and Prevention speaks during an event at The Queen theater in Wilmington, Del., Tuesday, Dec. 8, 2020.
Susan Walsh | AP

The United States needs to rapidly deploy Covid-19 vaccines and ramp up its surveillance before highly contagious variants take hold or the virus mutates again and makes the pandemic even worse, CDC Director Dr. Rochelle Walensky said Wednesday.

Three variants first identified in the U.K., South Africa and Brazil have given researchers some concern, according to a research opinion she wrote with White House Chief Medical Advisor Dr. Anthony Fauci. A CDC study published in January warned that the variant found in the U.K., known as B.1.1.7, is likely to become the dominant strain circulating in the U.S. by March.

The B.1.1.7 variant has proven to be highly transmissible, and "preliminary data suggest the possibility of increased severity of disease with infection," Walensky, Fauci and Dr. Henry Walke, the CDC's Covid incident manager, wrote in the viewpoint published Wednesday in the the Journal of the American Medical Association, or JAMA.

Walensky told JAMA in a separate interview Wednesday that the variant is thought to be about 50% more transmissible than previous strains and early data suggests it could be up to 50% more virulent, or deadly.

"Modeling data have illustrated how a more contagious variant, such as B.1.1.7, has the potential to exacerbate the trajectory of the US pandemic and to reverse the present downward trend in new infections and further delay control of the pandemic," Walensky said in the paper.

The rise of variants

So far, the U.S. has identified at least 1,277 Covid-19 cases with the B.1.1.7 variant from the U.K., 19 of the B.1.351 variant, which was discovered in South Africa, and three cases of the P.1 variant found in Brazil, according to recent data from the CDC.

Surveillance for the variants at one commercial laboratory in early February suggests that nationwide, the prevalence of the B.1.1.7 variant is likely approaching 1%, though the prevalence in some states could exceed 2%, according to the paper.

However, the more the virus circulates and infects other people, the more chances it's given to mutate. That's part of the reason why global health experts have pushed for people to double down on public health measures, like social distancing, frequent hand washing and mask wearing, until vaccines can be deployed and populations can reach so-called herd immunity.

A faster spreading virus would also mean more people would need to be vaccinated to build an umbrella of immunity, experts have said. In the U.S., the level of viral spread in the community needs to be "aggressively decreased" and Americans should postpone travel and avoid crowds to ensure the variants don't continue spreading, the top federal health officials wrote in their viewpoint.

"The more they mutate, the more we're likely to see dominant variants that could really emerge and become a problem for us," Walensky told JAMA. "So the best thing we can do to prevent these in general is to have less disease circulating, less virus circulating."

Accelerate vaccinations

The U.S. needs to accelerate the pace of vaccinations to "decrease transmission and thereby viral replication that creates opportunities" for the concerning variants to emerge, "especially where virus is most rapidly spreading," the officials said.

Early data suggests that the B.1.351 variant first found in South Africa may be able to escape natural immunity acquired by people who recover from Covid-19, they said, adding that "currently employed vaccines might be less effective at preventing infection due to this variant."

The problem isn't isolated to the U.S. So far, countries that have been able to roll out vaccines to their populations have predominantly been in higher-income nations that have supply agreements with the pharmaceutical companies.

"If there's still virus circulating in huge volumes in other countries and other parts of the world ... they continue to be a threat to us because, in fact, those variants continue to threaten whether our vaccines will continue to work. So this is a global problem," Walensky said.

Surveillance lacking

The nation's response not only should address the variants found in the U.K., South Africa and Brazil, but it should also be prepared to detect mutations that may arise domestically, Walensky said.

The country's infrastructure to conduct "genome sequence surveillance" for the variants in the U.S. has so far been underprepared to detect the circulating strains.

The CDC has partnered with public health and commercial laboratories to rapidly scale up the nation's genomic sequencing. In January, the U.S. was only sequencing 250 samples per week for the variants, which has since grown "to the thousands," Walensky said. However, she added that "we're not where we need to be."

"It's going to be a dial not a switch, and we need to dial it up," Walensky said.

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