With cases rising in parts of Europe and Asia, scientists fear that a highly contagious version of the omicron variant could soon lead to a rise in cases in the United States as well.
Experts also keep their eyes on another mutant: a rare delta-omicron hybrid that they say doesn’t pose much of a threat right now but shows just how insidious the coronavirus can be.
According to Dr. Eric Topol, head of the Scripps Translational Research Institute, the U.S. is likely to experience a spike in cases caused by the BA.2 omicron progeny starting in the next few weeks.
“We will inevitably see wave BA.2 here,” he said.
One reason? After about two months of falling COVID-19 cases in the US, restrictions on the pandemic have been lifted. Many people are taking off their masks and returning to enclosed spaces such as restaurants and theatres.
Dr. Anthony Fauci, the US government’s chief infectious disease expert, said on ABC’s “This Week” over the weekend that he also believes the US is likely to experience a “surge” similar to what’s happening in Europe, especially the UK. , where B.A. 2 is the dominant strain. He said he didn’t think it would be a “splash”.
In the UK, “it was the same situation as it is now,” Fauci said. “They have BA.2. They have relaxed some restrictions, such as wearing masks indoors, and have seen weakened immunity” from vaccines and past infections.
In the US, the latest data from the Centers for Disease Control and Prevention shows that the total number of COVID-19 cases is on a downward trend. But the share caused by BA.2 has grown significantly; this variant accounted for about 35% of new infections reported last week. There were about half of them in the Northeast.
Keri Altoff, a researcher at the Johns Hopkins Bloomberg School of Public Health, warned that the CDC case count understates the true numbers because some people are no longer tested and others are tested at home and do not report results. In addition, not every sample is genetically sequenced to determine a variant, she said.
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It’s clear, she said, “BA.2 is taking the stage.”
Scientists say that one of the reasons why this variant has gained popularity is is that it is about 30% more infectious than the original omicron. Research shows that, in rare cases, people can get sick even if they already had an omicron infection, although this doesn’t seem to cause a more serious illness.
Vaccines are equally effective against both types of omicrons, but breakthrough infections are possible. And experts point out that vaccination rates in the US are lower than those in the UK. About 74% of those aged 12 and over are fully vaccinated in the US compared to 86% in the UK.
“We have to emphasize that we are not protected in this country compared to other countries,” Topol said.
However, not all experts are equally concerned about the rise in BA.2 cases in the US. Dr. James Musser, head of genomic medicine and infectious diseases at Houston Methodist, said the variant has so far only caused 1% to 3% of cases in his medical system. Cases there are usually closely related to what happens in the UK.
He called BA.2 “something we keep an eye on” but said, “I don’t lose sleep” because of it.
This is how many scientists view the other variant, which some in the community call a “deltacron”, a hybrid containing genetic information from both the delta and omicrons.
Earlier this month, Maria Van Kerkhove of the World Health Organization said the hybrid had been detected at “very low levels” in France, the Netherlands and Denmark. And two recent studies that have not yet been peer-reviewed point to a small number of cases in the US.
Much remains unknown about the hybrid. There is no evidence that it causes a more serious illness, and it does not appear to infect many people. CDC researchers identified 9 specimens, seven from the Mid-Atlantic region in study published on Monday which has not yet been peer reviewed. Topol, who was not involved in the study, said there was no evidence that the virus could spread.
According to Dr. Stuart Campbell Ray, an infectious disease expert at Johns Hopkins University, it is common for coronaviruses to shuffle gene segments. With the simultaneous circulation of two variants, people can become infected with double infections, and a “daughter virus” can appear.
Given the virus ability to spawn new mutants — and BA.2 growth — experts say people should get vaccinated if they don’t and keep their masks handy.
“Be alert,” Poplar said. “It’s not over yet.”