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HHealth officials have identified the first US cases of Covid-19 caused by a rapidly spreading form of the coronavirus initially seen in South Africa, in two people in South Carolina.
Neither person has traveled to countries where the variant has been confirmed and there is no connection between the two, South Carolina health officials said Thursday. This indicates that there was a local spread of the variant after it arrived in the United States. One case was found in the Pee Dee area of South Carolina and one in the Lowcountry.
Thursday’s announcement means that three variants of the coronavirus that appear to be more contagious and have emerged in recent months have all been documented in the United States. But in a way, the news did not surprise the experts. They had said for weeks that the variant that first arose in South Africa, called B.1.351, was likely already in the United States, but that country’s limited surveillance system for different iterations of the coronavirus meant that the variant probably went unnoticed once imported. via a traveler and could even have spread.
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Earlier this week, Minnesota health officials confirmed the first case of Covid-19 caused by P.1, a variant first identified in Brazil. There have been a few hundred US cases of the B.1.1.7 variant, which initially appeared in the UK.
All three variants are believed to be more transmissible than earlier forms of the coronavirus and, if left unchecked, could lead to more cases overall by infecting more people faster. The Centers for Disease Control and Prevention has estimated that B.1.1.7 could become the dominant form of the coronavirus in the United States by March.
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“It’s critical that we all continue to do our part by taking small steps that make a big difference,” Brannon Traxler, interim director of public health for South Carolina, said in a statement. “These include wearing our masks, staying at least six feet from each other, avoiding large crowds, washing your hands, getting tested often and, when we can, ourselves. get vaccinated. These are the best tools to prevent the spread of the virus, regardless of the strain. “
All three variants have evolved independently – all viruses mutate and sometimes have alterations that give them a transmission advantage – but share some of the same mutations.
B.1.351 and P.1 in particular triggered a different set of alarms than that of B.1.1.7. Studies have shown that mutations that appear in both variants can help the virus partially evade the human immune response, perhaps making it more likely that the variants could re-infect people who have had an initial case of Covid-19. .
These studies have raised concerns that existing Covid-19 vaccines – which were designed based on earlier iterations of the virus – might not be as effective against the variants.
On Thursday, for example, Novavax said its investigational Covid-19 vaccine was 90% effective in a trial in the UK, but in a separate trial in South Africa it was 49% effective. Of the cases in the South African trial for which sequencing data were available, 93% were caused by B.1.351.
Other vaccines made in different ways may see less decline in effectiveness, although more studies are ongoing. With the mRNA vaccines from Pfizer-BioNTech and Moderna, it appears that the injections lose some of their neutralizing power against some of the mutations seen in both P.1 and B.1.351, but that the immune response elicited by the vaccines is so extremely powerful that the shots can withstand losing some of their punch while protecting people from getting sick with Covid-19.
On Monday, Moderna said his injection should still be effective against B.1.351 despite the neutralizing antibodies generated by the vaccine fail to recognize the form of the virus as well as other forms. Essentially, the antibody response induced by the injection should still be sufficient to help people avoid Covid-19. However, the question arises as to whether the immune response of vaccines will last as long against variants as previous viral iterations.
So far, studies on the impact of variants on Pfizer and Moderna vaccines have largely focused on neutralizing antibodies, but experts note that the injections rally other parts of the immune system as well – including T cells. , B cells, and other types of antibodies – providing additional reasons why current vaccines are still expected to largely work against variants.
Still, experts believe the coronavirus may one day detect a certain series of mutations that threaten the overall effectiveness of vaccines, so, they say, vaccine makers and regulators should start considering what will be needed to bring up to date. day vaccinations to better match the circulation. forms of SARS-CoV-2, the scientific name for the coronavirus causes Covid-19.
Moderna and Novavax said they are investigating recalls designed specifically against B.1.351.
For now, the most pressing concern about the variants, experts point out, remains their infectivity. The World Health Organization, for example, warned on Thursday that B.1.351 was leading to an increase in cases as it spread from South Africa to other African countries, Matshidiso Moeti, the regional director of WHO, claiming that the continent “is at a crossroads. . “
Cases in the United States remain sky-high, but they are dropping back from early-month highs. If any of the variants take off, the country could see another peak. It will also take a larger portion of the population to be immune to the virus to slow the spread of more contagious variants, adding even more pressure to the U.S. vaccination campaign.
Over the past week, British scientists reported that the variant first seen there, B.1.1.7, could also be deadlier than other forms of the virus, although they are still analyzing them. national data.
In general, experts actually fear a more transmissible virus more than a virus that is proportionately more deadly; more infectious variants could lead to more deaths overall, although they are not more fatal just because they lead to so many more cases.
But with B.1.1.7, “unfortunately it looks like this virus could be both,” said John Edmunds of the London School of Hygiene & Tropical Medicine.
This story has been updated with details from the clinical trials of Novavax.
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