As health officials in the United States announced a second and possibly a third person infected with a new, more transmissible strain of the SARS-CoV-2 virus, infectious disease experts feel a sense of déjà vu.
A little less than a year ago, the early response to the coronavirus crisis was stifled by the inability to scale up tests to detect the virus and limit its spread. It is again unclear how common the new strain, which first emerged in the UK, is found in the US. A possible and probable case has already been detected in Colorado, and one case has been reported in California. But the distribution of the variant is probably not there.
“It feels a lot like the time between January 19 or so when we had the first case in the Seattle area and six weeks later, when it suddenly seemed like we had community transfer in California and Seattle and who knows where else,” Michael said. Worobey, a professor of evolutionary biology at the University of Arizona, said. “It does feel that way.”
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Trevor Bedford, a computer biologist at the Fred Hutchinson Cancer Research Institute, told STAT he does not believe the new variant, called B.1.1.7, is still widespread. There are 250 genetic sequences of SARS-2 viruses from December cases in the US recorded in an international database for viruses known as GISAID; there is not a B.1.1.7 among them, Bedford said. But he believes it can only be a matter of time.
“How I could imagine it working … looks a lot like January, February,” he said. ‘There are seed events that have taken place across the country. Some took, others did not … And you might think it would be more likely to be in places like New York and Boston with good travel connections to London, but it might just be picked up a little differently. ‘
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Worobey agrees that the new variant is probably already spreading in a number of parts of the country and traveling under the radar because the US is not doing enough sequencing of SARS-2 viruses.
“We are a bit behind the eight ball in terms of our genomic order, both in terms of absolute numbers and the kind of delay between sampling and getting the series out there, compared to the UK,” Worobey said. He warned that if the US did not find the business and the slow spread, it would probably see the same kind of rapid spread of the variant as the UK saw.
The new variant contains unusual mutations, including some that alter the behavior of the virus. It appears to be significantly more transmissible, increasing the rate at which infected people infect others.
There is so far no evidence that the variant causes serious diseases. But hospitals are trying to treat Covid patients as they are; more infections can lead to a higher mortality rate due to reduced quality of care.
“The mortality rate increases when healthcare systems are overwhelmed,” said Nahid Bhadelia, medical director of the special pathogenic unit at Boston Medical Center. “That’s just how it works.”
There are attempts to find out how widely the new variant is distributed – one of them led by Worobey’s laboratory. His team is trying to develop a test that can be used to test whether there are different viruses in wastewater from sewage systems in the community. If the test works, he will send test materials to other laboratories, test samples in their own laboratory or share the recipe according to the laboratory to make the primers and probes to use the test widely.
“I do think that wastewater in the short term would be the best way to get your hands on it better than waiting for the weird lab like Colorado to see one of them in an individual sample,” Worobey said.
The Centers for Disease Control and Prevention is also stepping up efforts to increase the number of SARS-2 viruses, officials said Wednesday.
Gregory Armstrong, who oversees the CDC team to monitor virus variants, said the national SARS-CoV-2 strain monitoring system, launched in November, is expanding to be able to handle 750 samples submitted by the state each week to handle for sequence and study. . The CDC also works with national reference laboratories in the country, providing funding for the sequencing of a number of times as many viruses. The hope is to reach about 3,500 a week, Armstrong noted.
He said experts from the CDC and elsewhere do not believe that the mutations contained in B.1.1.7 will significantly undermine the protection generated by Covid vaccines in use or in production. “It can have a small impact. But keep in mind that the amount of immunity caused by natural infection or vaccination is large enough to have a slight decrease [antibody] titer may have no noticeable effect, ”Armstrong said.
However, Bedford says the increasing use of vaccine will put additional pressure on SARS-2 viruses to mutate in an attempt to evade the protection of the vaccine.
“It’s even more of an argument to try to get herd immunity faster and reduce vaccination transmission,” he said. “The faster we can get enough people vaccinated, the better we will be at preventing this variant and other future mutants from spreading.”