A new subvariant of the omicron strain is highly infectious...

A new subvariant of the omicron strain is highly infectious but unlikely to cause extensive deaths or hospitalizations among those vaccinated and boosted against COVID-19, according to medical experts. Credit: Sipa USA via AP/Pavlo Gonchar / SOPA Images

A new COVID-19 subvariant that is particularly good at infecting vaccinated people or those immune from previous infection is poised to become the next dominant strain, medical experts said Wednesday.

Even so, according to experts, the rise of the BA. 5 subvariant of the omicron strain is unlikely to cause extensive deaths or hospitalizations among those vaccinated and boosted against COVID-19.

“BA. 5 is the one that is going to eclipse them all in the next month or so," said Dr. Bruce Farber, chief of public health and epidemiology for Northwell Health. "It is well on its way."

In the region comprised of New York, New Jersey, Puerto Rico and the Virgin Islands, the BA. 2.12.1 subvariant remains dominant at about 53% of confirmed new cases, according to the Centers for Disease Control and Prevention.

BA. 5 however is increasing steadily, accounting for about 31% of new cases as of the week ending last Saturday, the CDC said. The BA. 4 subvariant accounted for about 12% of new cases.

New variants and subvariants of COVID-19 continue to emerge as more contagious than older versions, Farber said. That cycle is not expected to end any time soon — or possibly ever, he said, meaning the virus could be a part of daily life.

BA. 5  has not led to a dramatic increase in the numbers of deaths or hospitalizations caused by the virus, experts said. It has led to substantial increase in "breakthrough” cases among the vaccinated and those with prior immunity, said Farber and Sean Clouston, an associate professor of public health at Stony Brook University.

The numbers of new confirmed cases on Long Island appear to have hit a plateau in recent days, though there was a slight uptick that may be connected to end-of-the-school year ceremonies and gatherings, Clouston said.

What remains unclear, he said, is whether this is the start of a new wave, though the next couple of weeks will be key. The hope is, with people moving outdoors for summer activities, the numbers will start to drop, he said.

The seven-day positivity average for Long Island was 7.63% in test results from Monday, an increase from 7.49% a day earlier. Nassau County registered 384 new cases on Monday, while Suffolk had 369. Medical experts have said those are vast undercounts because many people are doing home tests whose results are not registered with the state.

Both Clouston and Farber said it is hard to accurately predict what will happen next.

“With COVID, every time we get one of these waves I am kind of surprised by something,” Clouston said. “It changes quickly and it changes to adapt to its new conditions.”

Still, Farber said, “I don’t think rates are going to skyrocket until potentially in the fall because we are in a good position in terms of the season and being outdoors.”

As the new subvariants take over, experts said it is likely that the vaccines will have to be tweaked in the fall.

“The current vaccine, which is a long, long outdated vaccine, was made through the Alpha strain, which you can’t find if you wanted to nowadays,” Farber said.

Vaccine researchers and manufacturers “are going to be obligated to do something even if it’s not perfect and even if it’s a modest improvement,” he said.

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