New COVID variant spreads quickly in NJ. Here's what you need to know about BA.2

A new COVID variant is spreading quickly across New Jersey a month after it was first detected in the state, new data released this week shows.

The BA.2 variant appears to be on its way to becoming the dominant COVID strain in the region, having more than doubled in prevalence in two weeks, according to the U.S. Centers for Disease Control.

On Thursday, Gov. Phil Murphy said he expects cases to rise in New Jersey due to surges seen in parts of Asia and Europe. But he said he doesn't expect to reinstate "universal statewide mandated protective measures."

It is unclear how much of an impact BA.2 will have on New Jersey and whether it is as severe as prior strains.

BA.2 is considered a "sublineage" of the highly transmissible omicron variant called BA.1, which was responsible for the surge that hit New Jersey hard from mid-December through mid-January.

BA.2 has a different genetic sequence from BA.1 and was first dubbed the "stealth variant" because it wasn't as easy to detect.

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How fast is BA.2 spreading in New Jersey?

Since it was first detected in New Jersey in late January, BA.2 has spread quickly in six weeks.

It made up 39% of COVID strains in New Jersey, New York, Puerto Rico and the U.S. Virgin Islands for the week ending on March 12 — a sizable jump from prior weeks, according to the latest CDC data.

• Feb. 12: 3.7%

• Feb. 19: 8%

• Feb. 26: 16.7%

• March 5: 25.4%

• March 12: 39%

New Jersey's latest variant report shows BA.2 at only 9.1%, but that data is old. It uses test results from the four weeks leading up to Feb. 26.

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Does BA.2 spread faster? Is it more lethal?

Studies have shown that BA.2 is "inherently more transmissible" than omicron BA.1, according to the World Health Organization.

What's not yet known is if BA.2 causes severe illness the way omicron BA.1 did, which prompted a rapid surge in cases, hospitalizations and deaths for a month before plummeting just as quickly.

While omicron BA.1 was considered milder than both COVID's original strain and the delta variant, more than 2,000 New Jerseyans died during its short peak.

"We often don't know until it's too late," said Stephanie Silvera, an infectious disease specialist at Montclair State University. "That's been the problem with managing these surges. Deaths are one of the last impacts we see."

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Is New Jersey seeing any impact?

So far, it doesn't look as if BA.2 is making a noticeable impact. But public health officials say they are closely monitoring its spread.

Key COVID metrics such as cases, hospitalizations and deaths continue to drop almost every day, and are hovering around levels last seen in July before the delta variant surge.

As of Tuesday night, COVID hospitalizations were at 438, intensive care admissions at 81 and ventilator use at 49 — a decrease of more than 90% since omicron's peak in mid-January.

Only 559 new cases were reported on Tuesday compared to a high of 33,459 on Jan. 7 when omicron was peaking and record numbers of tests were being taken during and after the holiday season.

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Daily reported deaths have been in the low double digits and single digits in March after fluctuating between 80 and 110 most days in January.

The plummeting metrics led Murphy to lift the last two remaining state mask mandates — in schools and public buildings — in what he calls a return to normalcy.

But New Jersey health officials are uncertain what BA.2 will do.

"It’s difficult to predict how COVID-19 variants or any other emerging respiratory virus will evolve over time and what their specific impacts will be," said Dr. Tina Tan, the state epidemiologist. "And it is hard to predict whether a surge in BA.2 will translate to increased hospitalizations or deaths at this time."

Are vaccines and natural immunity effective against BA.2?

Vaccines were shown to be as effective against BA.2 as they were against omicron BA.1, according to British scientists. That means the vaccines may not prevent infection, but they work well in fending off severe illness.

If you were infected by omicron BA.1, you may also have good protection against BA.2, according to the World Health Organization.

While reinfection is possible, studies suggest that infection with BA.1 "provides strong protection" against reinfection with BA.2.

The hundreds of thousands of infections in New Jersey during the omicron surge "suggest that many residents may have some protection against BA.2," said Tan.

How does NJ compare to the rest of the US?

As with almost every COVID variant, New Jersey and the rest of the Northeast were hit first with BA.2, and are currently outpacing the rest of the U.S.

In the CDC's Region 2 — New Jersey, New York, Puerto Rico and the U.S. Virgin Islands — 39% of COVID cases are the BA.2 strain, compared to the U.S. average of 23.1%.

New England is close behind at 38.6%. California, Nevada and Arizona come in third at 27.7%.

What's happening in other parts of the globe?

Europe and parts of Asia have seen a rise in cases in the past few weeks, but it's not yet clear how much BA.2 is to blame.

The United Kingdom, the Netherlands, Germany, Switzerland and Italy saw an upswing last week. Many European countries have begun treating the virus as a part of daily life and are forgoing full shutdowns.

China ordered a lockdown of residents in the city of Changchun, closed schools in Shanghai and urged the public not to leave Beijing last weekend amid a new spike.

Hong Kong has seen its worst spike in recent weeks after limiting COVID's spread for almost two years with some of the world's most stringent health mandates. Hong Kong has reported more than 700,000 COVID-19 infections and about 4,200 deaths, most of them in the past three weeks, according to Reuters.

Will other variants emerge?

The more times a virus replicates, the more chances it has to mutate into a stronger strain, as seen with delta and omicron.

That has some public health experts worried about the latest surge in Asia and elsewhere.

"I’m more worried that the sheer biomass of virus in these places that are now experiencing major waves of omicron will lead to the emergence of new strains, of which we in the U.S. have not yet experienced," said Daniel Parker, an infectious disease expert at the University of California, Irvine. "That could certainly lead to spikes in cases like what we saw with delta and omicron."

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This article contains information from USA Today.

Clarification: Some of the percentages regarding the prevalence of BA.2 in Region 2 have changed as the CDC has received more data.

Scott Fallon has covered the COVID-19 pandemic since its onset in March 2020. To get unlimited access to the latest news about the pandemic's impact on New Jersey, please subscribe or activate your digital account today.

Email: fallon@northjersey.com

Twitter: @newsfallon

This article originally appeared on NorthJersey.com: BA.2 variant: What to know about new omicron COVID strain