The BA.2 COVID variant: what you need to know

A new COVID variant, first discovered two months ago, is making its way across the US and spreading faster in the Northeast and West, new data released this week shows.

According to the US Centers for Disease Control and Prevention, the BA.2 variant appears to be on track to become the dominant COVID strain, doubling roughly every week for the past month.

BA.2 is considered by the World Health Organization to be a “subline” of the highly transmissible ommicron variety. It is a different version of ommicron than BA.1, which was responsible for the wave that hit the northeast at the end of last year.

It has a different genetic sequence than BA.1 and was first referred to as the “stealth variant” because it was not as easy to detect.

Infections around the world are largely due to the BA.2 version of ommicron. In the US, BA.2 accounted for about a quarter (23.1%) of cases for the week ending March 12, the CDC says. That’s over 14.2% in the week ending March 5.

How fast is BA.2 spreading in the US?

BA.2 made up 39% of cases in New Jersey and New York the week ending March 12, up from 25.4% the week before, the CDC says. (Puerto Rico and the Virgin Islands are also included by the CDC in its breakdown of the COVID case in that region.)

In the Northeast (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont), BA.2 accounted for 38.6% of cases, up from 24% the week before, according to the CDC.

In the West, which includes Arizona, California and Nevada, BA.2 accounts for 27.7% of cases, up from 17.1% the week before. In the upper west, including Alaska, Idaho, Oregon and Washington, BA.2 accounted for 26.2% of cases, up from 16%, the CDC says.

BA.2 cases have surged in the rest of the US in recent weeks, accounting for 12% to 20% of cases in other states for the week ending March 12.

Does BA.2 propagate faster? Is it more deadly?

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

What is not yet known is whether BA.2 causes serious illness like omicron BA.1 did, leading to a rapid rise in cases, hospitalizations and deaths for a month before plummeting just as quickly.

Although omicron BA.1 was considered milder than both the original strain of COVID and the delta variant, it led to an increase in the number of COVID deaths in the US, according to the Center for Infectious Disease Research: 60,000 in January 2022, two times as much as in November. Policy at the University of Minnesota.

“We often don’t know until it’s too late,” said Stephanie Silvera, an infectious disease specialist at Montclair State University in Montclair, New Jersey. “That was the problem with managing these peaks. Deaths are one of the last consequences we see.”

What impact does BA.2 have?

So far, BA.2 doesn’t seem to be 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 fall nearly every day, hovering around levels last seen in July before the rise in the delta variant.

Daily reported deaths ranged from 1,685 to 2,076 per day in March, after deaths of 3,000 or more per day for much of January and February.

The plummeting statistics have led to the lifting of the mandates of state masks – in schools and public buildings – in what officials see as a return to normalcy.

On Thursday, New Jersey Governor Phil Murphy said he expects cases to rise in the state due to spikes in parts of Asia and Europe. But he said he doesn’t expect to reinstate “universal state-imposed protective measures.”

But health officials are unsure what BA.2 will do.

“It is difficult to predict how COVID-19 variants or any other emerging respiratory virus will develop over time and what their specific effects will be,” said Dr. Tina Tan, New Jersey State Epidemiologist. “And it’s hard to predict whether an increase in BA.2 will translate into more hospitalizations or deaths at this point.”

Are vaccines and natural immunity effective against BA.2?

According to British scientists, vaccines were found to be as effective against BA.2 as against omicron BA.1. That means the vaccines may not prevent infection, but they work well at warding off serious illness.

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

Although 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 microwave wave “suggest that many residents may have some protection against BA.2,” Tan said.

What is happening in other parts of the world?

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

The United Kingdom, the Netherlands, Germany, Switzerland and Italy experienced an uptick last week. Many European countries have begun to treat the virus as part of everyday life and forego full shutdowns.

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

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

Will there be other variants?

The more times a virus multiplies, the more likely it is to mutate into a stronger strain, as seen in delta and omicron.

That has some public health experts concerned about the latest wave in Asia and elsewhere.

“I’m more concerned that the pure biomass of viruses in these places, which are now experiencing large waves of omicron, will lead to the emergence of new strains, which we have not yet experienced in the US,” said Daniel Parker, an infectious agent. disease expert at the University of California, Irvine. “That could certainly lead to spikes in cases like we saw with delta and ommicron.”


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