At least one of two or more new SARS-CoV-2 modifications appears to have been introduced into community distribution in the United States, but they are unlikely to have much effect on vaccine efficacy or routine precaution, CDC officials said at a briefing.
The first reported U.S. case of the highly transmitted coronavirus variant first seen in Britain (known as SARS-CoV-2 VUI 202012/01) was confirmed Tuesday in a Colorado man without travel history. The strain may be at least 56% and up to 70% more susceptible than the “wild type” virus, although it is neither harsh nor lethal. The British variant seems to have been circulating there since September 2020.
Another variety that can be extracted from South Africa has arisen independently and seems to be spreading internationally now, and Nigeria has reported that another variant has arisen there. Neither was exiled in the United States.
“We expect to see new changes emerge over time,” Henry Walke, MD, MPH, CDC-19 CDC event manager, said during Wednesday’s press conference.
How many variables that have appeared so far is simply “impossible to answer,” because it depends on how you set the threshold for how different a virus must be. representing a variety, said Gregory Armstrong, MD, director of the CDC Advanced Molecular Proof Program.
The government has been working on a strain analysis system since November with two national laboratories to study genetic sequences of SARS-CoV-2 samples from across the country to see what the new changes are. mentioned. Armstrong said decisions are expected over the next few days.
It is not yet known for sure how well the vaccines and other treatments will work. One check posted on the preprint server medRxiv suggest that convalescent plasma does not work as well against changes.
However, “from what we know from experience with this strain and other mutations it is unlikely to have a significant effect on vaccine – induced immunity or immunity that exists from previous strains,” Armstrong said.
“We know that some of these mutations can lead to lower efficacy of monoclonal antibodies,” which binds one specific portion of the target antigen, Armstrong noted. But immune responses derived from diseases or vaccines recognize several components of the spike protein, he said.
“Experts generally agree that mutations like this are unlikely to have a significant impact on nesting,” he said. “It may have a small effect, but keep in mind that the level of immunity caused by a natural infection or by a vaccine seems to be large enough that a reduced titer may not have any effect at all. . “
In vitro studies of UK variables are ongoing and should provide a more definitive response, Armstrong said.
In addition, Walke said, there is no reason to think that the proposed measures to reduce transmission will not work – washing hands, maintaining speed, wearing a mask, and avoidance of large gatherings – against these variables.
“We are pushing the same messages that we have been pushing all along,” he said. “While we believe that this change that came from the UK … outweighing the wild type, we strongly believe that the mitigation measures we now have in place will work in our direction. “
Last updated December 30, 2020