Health

New subvariants, family gatherings may bring more Covid-19 after the holidays, but experts do not expect a serious increase

New subvariants, family gatherings may bring more Covid-19 after the holidays, but experts do not expect a serious increase

New subvariants, family gatherings may bring more Covid-19 after the holidays, but experts do not expect a serious increase



CNN

As millions of Americans travel to gather with friends and family over the next few days, there’s a good chance that Covid-19 will follow.

Experts expect Thanksgiving gatherings to stir up social media and give new sub-variants of the coronavirus fresh pockets of vulnerable people to infect. As a result, the number of cases and hospitalizations may accelerate after the holidays, as in the previous two years.

Covid-19 is not unique in this regard. Thanksgiving gatherings have the potential to increase the spread of other viruses, especially respiratory syncytial virus, or RSV, and influenza, which are already at high levels for this time of year.

“We have seen that in some regions the number of RSV is starting to decrease. The number of flu is still on the rise. And we are worried that after the holiday gathering, many people will gather, so that we could also see an increase in Covid-19 cases,” said Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, said Tuesday on CNN.

But things have been relatively calm on the Covid-19 front. Experts say that may not stay that way for long.

“Covid positivity is increasing,” said Shishi Luo, associate director of bioinformatics and infectious diseases at the genetic testing company Helix, which tracks variants of the coronavirus. “Fastest growing among 18-24 year olds” in the Helix sample.

It is the first time that test positivity has increased in Helix data since July.

When the test positivity increases, it means that more of the tests for Covid-19 are giving positive results, and this can be an indication that transmission is increasing.

“We should expect more cases,” Luo said. “Whether they’re being measured the way we’re currently measuring cases, I don’t know, but in general I think you should see more people who are sick. I definitely am.”

The official case count may not detect the growing number of cases as quickly because people are mostly testing for Covid-19 at home and not reporting their results – if they are tested at all.

The BQ sub-variants of the Omicron became dominant in US transmission. BQ.1 and its offspring BQ.1.1 are descendants of BA.5; they have five and six key mutations in their spike proteins that help them avoid vaccine- and infection-induced immunity. Due to these changes, they grow faster than BA.5.

For the week ending November 19, CDC estimates that BQ.1 and BQ.1.1 caused approximately half of all new cases of Covid-19 in the US. But so far they have risen to supremacy without much impact.

The number of Covid-19 cases, hospitalizations and deaths have remained at the same level over the past four weeks. But it didn’t disappear: more than 300 on average Americans are dying and 3,400 people are every day in the hospital with Covid-19, according to the CDC.

No one knows exactly what will happen with the BQ variants. Many experts say they hope we won’t see the big waves of past winters — certainly nothing like the original Omicron variant, with a staggering peak of nearly a million new daily infections.

There is reason for optimism on several fronts.

First, there is the experience of other countries such as the UK, where BQ.1 has outperformed its rivals to dominate transmission even when cases, hospitalizations and deaths have fallen. Something similar happened in France and Germany, notes Michael Osterholm, an infectious disease expert who directs the Center for Infectious Disease Research and Policy at the University of Minnesota.

“Cases went up in France and Germany right before the subvariants came in. Then the subvariants came in, and the cases actually went down,” he said.

Bill Hanage, an epidemiologist at the Harvard TH Chan School of Public Health, believes that our behavior and our social contacts may be a greater determinant of whether cases rise to this extent than any leading variant.

He thinks it’s likely we’ll see an increase in cases that could peak around the second week of January — as in previous years — but that it won’t have a big impact on hospitalizations and deaths.

Andrew Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, says that’s likely because the benefits of BQ.1 are incremental, not drastic.

“It probably has a bit more of a fitness advantage, so what we’re seeing is a gradual replacement without a big change in the overall number of Covid-19 cases,” he said.

All this is not to say that BQ.1 and BQ.1.1 will have no impact. They have shown marked resistance to antibodies that are available to protect and treat people who are susceptible to severe Covid-19 infections. From that point of view, there is good reason for people to be cautious if they have a compromised immune system or will be around someone who does.

But these sub-variants will appear at a time when population immunity is higher than ever, thanks to vaccines and infections. That’s a very different situation than the virus faced when Omicron emerged a year ago, and it should also help dampen any incoming waves, Pekosz says.

“With many people now primed and vaccinated and with people having immunity from Omicron infection, it’s also a very, very different kind of population in which a variant can occur,” he said. “All the signs are, I think, the best part of the scenario in terms of not seeing this big increase in cases.”

If there is any cause for concern about BQ in the US, it might be this: Americans are not as well vaccinated or boosted as other countries. CDC data shows that two-thirds of the population has completed the primary series of Covid-19 vaccines, and only 11% of those eligible have received the updated bivalent booster. In the UK, 89% of the population aged 12 and over completed the primary series and 70% received a booster.

New research shows that a country’s vaccination rate is more important than any other single factor when it comes to the effects of variants on a population.

Scientists at Los Alamos National Labs recently completed study investigating what drove the effects of 13 dominant coronavirus variants as they passed from one to another in 213 countries. The study includes data up to the end of September and was published as a preprint prior to peer review.

Among the 14 variables that affected the speed and height of new waves of Covid-19, population vaccination rates were by far the most important.

The number of previous cases in the country, the percentage of people wearing masks, the average income and the percentage of the population over 65 were a distant second, third, fourth and fifth.

How many other variants are in the mix when a new one emerges is also an important factor, says senior study author Bette Korber, a lab associate in the Theoretical Biology and Biophysics Group at Los Alamos.

She points to the Alpha variant, B.1.1.7, and how it performed in the UK compared to the US.

“When he came through England, he was extremely fast, but he was much slower in America,” Korber said.

By the time Alpha arrived in the United States, we were developing our own California and New York variants “that were very distinctive and had a competitive advantage over what she had to go up against in England,” Korber said, which has probably slowed down here.

The CDC is tracking a soup of more than a dozen Omicron subvariants causing cases in the U.S., and that diversity could eventually help dampen any surge over the winter.

But Korber makes no predictions. She says it’s just too hard to know what will happen, pointing to Asia as the source of her uncertainty.

Asian countries are fighting waves powered by recombinant XBB, a sub-variant that really hasn’t had much of a presence in the US. BQ variants came later, but she says they look impressive against XBB, which is also very immune-resistant.

“BQ is really pushing it,” Korber said. “So I don’t think it’s yet possible to say for sure what might happen in the US.”

“It’s a good time for me, when possible, to wear masks,” she said. Masks protect the wearer as well as others around them. “And get an amp if you’re eligible and the time is right for you,” especially as we gather around the table to mingle with our friends and family.

“It’s time to be a little more careful to prevent that wave that we don’t want to happen, or at least make it less of a blow,” Korber said.



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