Although COVID-19 cases and hospitalizations caused by the omicron BA.5 sub-variant continue to decline in the United States, the proportion of infections attributed to other omicron branches is increasing.
According to data from the Centers for Disease Control and Prevention, BA.5 currently accounts for 67.9% of new virus cases as of last Friday.
The remaining cases consist of BA.4.6 – which has been circulating in the United States for weeks – and recently identified sub-variants such as BQ.1, BQ1.1 and BF.7, which are spreading mainly in Europe.
Sub-variants have been attributed to an increase in infections in Europe. According to the latest weekly report from the World Health Organization, released on October 12, over 1.66 million cases of COVID-19 have been recorded across the continent, compared to more than 1.53 million cases recorded in the previous report. released on October 5
Throughout the course of the pandemic, Europe has been seen as a benchmark for what has come to the United States
Should we worry about the new subvariants? Experts told ABC News that the US could see a new wave as we enter the colder months and move indoors and it’s important to stay alert.
“In the coming months, I think there is a reasonable expectation that we will likely see a wave of falling,” said Dr. John Brownstein, epidemiologist and chief innovation officer at Boston Children’s Hospital and a contributor to ABC News. “But the size of that wave, I think, is still much in question.”
What are the new sub-variants?
The sub-variant that makes up most of the cases after BA.5 is BA.4.6. According to the CDC, an offshoot of the omicron BA.4 subvariant is estimated to account for 12% of new cases.
Then there are new sub-variants, which have recently started to spread steadily in the United States: BQ.1 and BQ.1.1, both derived from BA.5 and together make up 12% of the new cases. This is a rapid rate of increase considering they accounted for only 3% of new cases for the week ending October 1.
“It seems to have come out of nowhere,” Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco, told ABC News. “But it didn’t actually come out of nowhere. It was first seen in Nigeria in the summer and then it has spread to other countries in Europe and Asia, and now to the United States.”
Another offshoot of BA.5 that is picking up speed is BF.7. It makes up 5.3% of new cases in the United States, up from 3.2% just two weeks earlier.
Meanwhile, there have been reports of another sub-variant called XBB, which combines multiple strains of the omicron variant and other COVID-19 variants and has been detected primarily in Asia. So far, it hasn’t been detected in the United States
Not much is known about any of these new sub-variants. Preliminary data suggest they have mutations that better evade immunity, whether from vaccination or previous infection, and may be more transmissible.
Another reason these offshoots could spread faster is because human behavior has changed. Travel is reaching pre-pandemic levels, children are back in school, and most restrictions, including masking, social distancing and vaccination requirements, are over.
There is good news. Since September, bivalent boosters have been approved in the United States targeting BA.4 and BA.5 for those 12 years of age and older and last week for those 5 years and older. Early data suggest that the booster increases the antibody response.
Since these sub-variants are related to BA.4 and BA.5, the booster is likely to provide at least some protection against them as well.
“I think there is a very reasonable expectation that vaccines, especially with the new boosters, will provide good protection,” Brownstein said. “But we still lack a lot of real-world data, especially as this new type of omicron variants of BA.5 and BA.4 are starting to take hold in various parts of the world.”
“We hope to have reasonable information from other countries that will help inform some of the forecasts for the coming months, but that data is still being compiled,” he continued.
Chin-Hong said it is also reasonable to expect, as with previous variants, that the Americans with the least protection are the most at risk.
“For unvaccinated people, people over the age of 65 who have never received a booster or people who are immunocompromised, can become more seriously ill and die if they don’t protect themselves,” Chin-Hong said.
Should we worry?
Brownstein said he thinks public health officials should remain vigilant and continue to monitor the spread of these sub-variants, but the public shouldn’t worry yet.
“I think it’s too early to tell the level of concern,” Brownstein said. “Of course, everyone should be concerned about how new variants emerge, especially when there is irregular vaccination in the United States and then around the world.”
He added: “The biggest burden of this concern should be on public health and scientists right now as we try to resolve it. [what’s happening]. “
Brownstein said Americans should be willing to change their behavior, such as re-masking indoors, if cases increase or a new variant emerges.
According to data from the CDC, the daily average of COVID-19 cases is 35,000 as of October 16, and the average estimate of new hospital admissions is 2,990 as of October 15.
Brownstein said that if the health care system is overwhelmed by a surge, city or state-level officials might consider masking to reduce the number of patients entering hospitals.
“I think clearly targeted masking, especially in high-risk places like health care facilities and long-term care facilities, will be key, because those places are tasked with protecting the most vulnerable,” Brownstein said. “On top of that, I think it will be really case driven at the local level.”
Sony Salzman of ABC News contributed to this report.