Covid variants may “undermine all of our efforts”

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

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New, highly transmissible variants of Covid-19 “may” “reverse” the nation’s control of the pandemic and could undermine “all of our efforts” against the disease if the virus proliferates in different parts of the world, Chief of the United States Centers for Disease Control and Prevention said on Wednesday.

Senior U.S. health officials have warned in recent weeks that the emergence of highly contagious variants, particularly of strain B.1.1.7 from the UK, could reverse the current downward trend in infections in the U.S. and delay the nation’s recovery from the pandemic.

The problem is not limited to the United States. As the coronavirus spreads, it makes large numbers of copies of itself, and each version is a little different from the previous one, experts say. The more people become infected, the more likely it is that problematic mutations will occur.

“Even if you weren’t necessarily inclined to be part of the global health effort, we have to, as any effort we are making here in this nation could potentially be undermined immediately from these variants,” said CDC Director Dr . Rochelle Walensky on Wednesday told the National Academy of Medicine and the American Public Health Association.

Scientists are not surprised by the emergence of the variants, and have repeated that the vaccines currently available should continue to work against them, although they may not be as effective as against the original “wild” strain.

Moderna announced Wednesday that it was shipping cans of a booster shot specifically targeting the variant common in South Africa known as the B.1.351 strain to the National Institutes of Health.

“We know this virus knows no geographic boundaries and that with the rapid spread of Covid-19 variants that can reverse advances in fighting this pandemic, it is more urgent than ever to address this reality,” said Walensky .

The US reports a weekly average of around 71,562 new Covid-19 cases per day, a 12% decrease from the previous week, and a significant decrease from the average of new cases in the US in early January of nearly 250,000 cases per day, according to a CNBC Analysis of data compiled by Johns Hopkins University.

Although not every country reports similar declines, global Covid-19 cases in the United States have declined for six consecutive weeks, according to the latest World Health Organization situation report released on Tuesday.

The decline is welcome news as countries battle to get their starting doses of Covid-19 vaccines. While some nations have been administering vaccines since December, some are just getting their first shots.

The first shipment of vaccines delivered under the World Health Organization’s COVAX program arrived in Ghana on Wednesday. Some experts have previously said that an equitable distribution of vaccines may be too late as wealthier nations have made their own deals with vaccine manufacturers and claimed their initial dose supply.

“The Covid-19 pandemic is a clear reminder of how closely we are connected as a global community,” said Walensky.

– CNBC’s Berkeley Lovelace Jr. and Natasha Turak contributed to this report.