The last thing people want to hear right now is that the coronavirus might have mutated yet again into yet another deadly variant, extending the pain, death and inconvenience of a pandemic that we long hoped would be over.

However, whether the subvariant of omicron known as BA.2 will hit the United States as hard as it’s hitting other parts of the world is hard to say at this point, an expert at modeling the disease said Wednesday.

The pandemic has been full of unpleasant surprises and BA.2 is no exception. Scientists estimate that it’s one-and-a-half times as transmissible as the original omicron strain, BA.1, and is overtaking it.

Europe, and particularly the United Kingdom, have seen an increase in the new variant in recent months, but that hasn’t been the case everywhere, said Stephen Kissler, a research fellow in the Department of Immunology and Infectious Diseases of Harvard University’s T.H. Chan School of Public Health.

“The question of if and when a surge is coming and how large is very open,” Kissler said in a Zoom conference with reporters. “I know that we’ve seen surges that are dominated by BA.2 across much of Europe. But in contrast, for example, in South Africa we saw a major BA.1 wave — that’s where we saw the omicron wave first — and now there’s a lot of circulation of BA.2, but it hasn’t really caused an increase in cases so much that it’s lengthened the decline and given the epidemic a very long tail.”

Kissler explained that vaccination rates in the U.S. are lower than those in Europe, but higher than those in South Africa. That could mean that more Americans have developed antibodies against the omicron variants than have Europeans.

“To the extent that that gives us protection against BA.2 we might see dynamics that are more similar to what happened in South Africa,” he said.

Seasonality and other factors likely will play a role, Kissler said, with spring in the United States being a season of relatively low spread and fall a season of relatively high spread.

So if there is a surge here of the new variant, how will it affect Americans of varying ages?

“In many ways it will likely resemble our experience with COVID-19 up to this point,” Kissler said.

And past experience has shown one factor to be hugely important: vaccination. 

Kissler said that being vaccinated, along with a booster dose, “really goes a long way toward helping to protect you from symptomatic disease and especially severe disease. The biggest delineation I imagine seeing is that people who are boosted will probably fare better than people who are unboosted.”

Another important factor is age, with the elderly having less natural resistance to all variants of the coronavirus than the young. Vaccines and boosters, though, can be a great equalizer.

“A vaccinated and boosted person over the age of 75, their risk is probably on the order of — if not lower than — an unvaccinated 20-year-old,” Kissler said.

COVID eventually will go from being a pandemic disease that spikes rapidly and overwhelms resources to an endemic one where a background level is present, sickening and even killing people, but in semi-predictable ways. Sadly, however, hopes that it will disappear altogether are small.

Looking forward, one simple public-health measure might be most effective, Kissler said.

“In many ways, one of the best things we can do to manage outbreaks is to just to continue to keep informing people how much COVID is circulating in their communities and make it just as accessible as a weather report,” he said. “A lot of data suggest that people tend to adjust their behavior accordingly.”

He said that probably won’t be enough to quell future waves of COVID, or be adequate in the face of major new variants.

“But as we continue to deal with COVID and we think about this permanent circulation of COVID-19 in the population — recognizing that there’s going to be different dynamics in different places, different patterns across the year — making it clear what’s happening in any given community at any given time through passive surveillance is probably the best thing we can do right now,” he said.

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