New variants, family gatherings may bring more Covid-19 after the holidays, but experts don’t expect a sharp increase



CNN

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

Experts predict that Thanksgiving gatherings will spark social networks and give new variants of the novel coronavirus new pockets of vulnerable people. As a result, cases and hospitalizations may increase after the holidays, as they have in the past two years.

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

“We’ve seen, in some areas, the RSV numbers start to trend downward. The influenza numbers are still going up. Many people are getting together,” Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, said Tuesday on CNN. After the holiday pool, and we may see increases in COVID-19 cases as well.

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

“COVID positivity is on the rise,” said Shishi Lu, associate director of bioinformatics and infectious diseases at genetic testing company Helix, which monitors coronavirus variants. “It’s increasing the fastest among people between the ages of 18 and 24” in Helix samples.

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

When test positivity increases, it means that a greater proportion of Covid-19 tests are returning positive results, and it can be an indication that transmission is on the rise.

“We should expect more cases,” Lu said. “Whether they’re measured by how we measure cases right now, I don’t know, but I think in general, you should see more people sick. I certainly am.”

The rapidly increasing cases may not be picked up by official counts because people are often tested for Covid-19 at home and do not report their results – if tested at all.

Omicron’s BQ sub-variants rose to dominate transmissions in the United States. BQ.1 and its subsidiary BQ.1.1 are descendants of BA.5; They have five and six major mutations, respectively, in spiky proteins that help them evade immunity from vaccines and infections. Because of these changes, they grow more rapidly than BA.5.

For the week ending November 19, the CDC estimates that BQ.1 and BQ.1.1 caused about half of all new Covid-19 cases in the United States. But so far, they’ve risen to dominance without much effect.

Covid-19 cases, hospitalizations and deaths have remained flat for the past four weeks. But it hasn’t gone away: On average, more than 300 Americans die and 3,400 are hospitalized each day from Covid-19, according to CDC data.

Nobody knows exactly what will happen with the BQ variants. Many experts say they feel hopeful that we won’t see the big winter waves of the past — certainly nothing like the original Omicron variant, with its staggering peak of nearly a million new daily infections.

There is reason for optimism on a number of fronts.

First, there is the experience of other countries such as the UK, where BQ.1 has outperformed its competitors for controlling transmission even as cases, hospitalizations, and deaths decline. 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.

He said, “The cases went up in France and Germany just before the sub-variants arrived. Then the variants came, and the cases really fell.”

Bill Hanage, an epidemiologist at the Harvard TH Chan School of Public Health, believes that our behavior and social contacts may be one of the bigger factors determining whether cases rise in this round than any variable in the lead.

He thinks we are likely to see a rise in cases that could peak around the second week of January – as has happened in past years – but which won’t have much impact on hospitalizations and deaths.

Andrew Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, says this is probably because the benefits of BQ.1 are incremental rather than radical.

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

All this does not mean that BQ.1 and BQ.1.1 will not have any effect. They have shown remarkable resistance to the antibodies that are available to protect and treat people exposed to severe Covid-19 infection. From this point of view, there is good reason for people to be careful if they have a weakened immune system or will be around someone who does.

But these sub-variants will drop at a time when the population’s immunity is higher than ever, thanks to vaccines and infections. It’s a very different situation from the virus he faced when Omicron came out a year ago, Pecos says, and that should also help quell any coming wave.

“With so many people now being boosted and vaccinated, and with some immunity to Omicron infections, it’s a very different kind of population landscape for the emergence of a variable,” he said. “I think all the evidence is the best part of the scenario in terms of not seeing these massive increases in cases.”

If there was a reason to be concerned about BQ in the US, it might be this: Americans are not as well immune or fortified as other countries. CDC data shows two-thirds of the population have completed the initial series of Covid-19 vaccines, and only 11% of those eligible have received an up-to-date bivalent booster. In the UK, 89% of the population over the age of 12 have completed their primary series, and 70% have been boosted.

New research suggests that a country’s vaccination rate matters more than any other individual factor when it comes to the effects of variants on the population.

Scientists at Los Alamos National Labs recently completed a study that delves into the effects of 13 prevalent types of coronavirus as they spread from one to another in 213 countries. The study includes data through the end of September and has been published as a preliminary print prior to peer review.

Of the 14 variables that affected the speed and height of new Covid-19 waves, the vaccination rate of a population was by far the most important.

The number of past cases in a country, the proportion of people wearing masks, the median income, and the proportion of the population over 65 years old were the second, third, fourth, and fifth distances, respectively.

The number of other variables in the mix when a new variable rises is also an important factor, says study senior author Pete Korber, a lab fellow in the Theoretical Biology and Biophysics Group at Los Alamos.

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

“When it came through England, it was very fast, but it was much slower in the Americas,” said Corber.

By the time Alpha got to the US, we were developing our own variants of California and New York “that were very special and had a competitive edge over what we had to contend with in England,” said Corber, which may have slowed the roll here.

The CDC is tracking a soup of more than a dozen sub-variants of Omicron causing cases in the United States, and this variety may end up helping quell any flurry during the winter.

But Korber makes no predictions. It is very difficult to know what will happen, she says, pointing to Asia as a source of her uncertainty.

Asian countries were dealing with waves driven by recombinant XBB, a variant that did not have a significant presence in the United States. The BQ variants arrived later, but she says they look impressive against XBB, who is also very immune dodgy.

“BQ is really taking a stand there,” said Korber. “So I think it’s not really possible to be sure yet” what could happen in the United States.

“For me, this is the time, when possible, to wear masks,” she said. Masks protect the wearer as well as others around them. “And get the booster if you qualify and this is the right moment for you,” especially when we gather around the table to feast with our friends and family.

“It’s time to exercise some extra caution to prevent that wave we don’t want to see happen, or at least make it a smaller bump,” Korber said.

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