December 1, 2023

The United States needs to deploy Covid-19 vaccines quickly and step up its surveillance before highly contagious variants catch in or the virus mutates again and makes the pandemic worse, said CDC Director Dr. Rochelle Walensky on Wednesday.

Three variants, first identified in the UK, South Africa and Brazil, have caused researchers some concern, according to a research suggestion shared with White House Chief Medical Officer Dr. Anthony Fauci, wrote. A CDC study published in January warned that variant B.1.1.7 found in the UK is expected to be the dominant strain in the US by March.

Variant B.1.1.7 has been shown to be highly transmissible, and “preliminary data suggest the possibility of increased disease severity with infection,” wrote Walensky, Fauci and Dr. Henry Walke, CDC’s Covid Incident Manager, in the position published Wednesday in the Journal of the American Medical Association or JAMA.

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

“Model data has shown how a more contagious variant like B.1.1.7 has the potential to exacerbate the US pandemic and reverse the current downward trend in new infections and further delay control of the pandemic,” Walensky said in the newspaper .

So far, the US has identified at least 1,277 Covid-19 cases with variant B.1.1.7 from Great Britain, 19 of variant B.1.351 discovered in South Africa and three cases of variant P.1 identified in Brazil according to the latest data from the CDC.

Monitoring of the variants in a commercial laboratory in early February suggests that the prevalence of the B.1.1.7 variant is likely to be 1% nationwide, although the prevalence in some states could exceed 2%, according to the paper.

However, the more the virus circulates and infects other people, the more likely it is that it will mutate. This is one of the reasons global health experts have urged public health measures such as social distancing, frequent hand washing and wearing of masks to double up until vaccines can be used and the population can achieve what is known as herd immunity.

A virus that spreads faster would also mean more people would need to be vaccinated to build an umbrella of immunity, experts have said. In the US, the levels of virus spread in the community must be “aggressively reduced” and Americans should postpone travel and avoid the crowds to ensure the variants do not spread further, the leading federal health officials wrote in their view.

“The more they mutate, the more likely we are to see dominant variants that really show up and could become a problem for us,” Walensky told JAMA. “The best we can do to prevent this from happening, in general, is to have fewer diseases circulating and fewer viruses circulating.”

Monitoring is missing

The nation’s response should not only focus on the variants found in the UK, South Africa and Brazil, but also be prepared to spot mutations that may occur domestically, Walensky said.

The country’s infrastructure for carrying out “genome sequence monitoring” for the variants in the USA has not yet been sufficiently prepared to detect the circulating strains.

The CDC has partnered with public health and trade laboratories to rapidly improve genome sequencing in the country. In January, the US sequenced only 250 samples a week for the variants, which have since grown “by the thousands,” Walensky said. However, she added that “we are not where we need to be”.

“It’ll be a dial, not a switch, and we’ll have to choose it,” said Walensky.

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