Dr. James Jarvis, who leads Northern Light Health's COVID-19 response, listens to speakers at a Bangor School Committee meeting in 2021. Credit: David Marino Jr. / BDN

A new COVID-19 variant has quickly become the dominant strain of the virus circulating in New England, but health care professionals don’t believe it causes more severe symptoms than its predecessors.

The new variant — XBB — may be more contagious than previous versions of the virus, but getting the most recent COVID-19 booster is still the most effective way to prevent severe illness, said Dr. James Jarvis, senior physician executive for Northern Light Health’s COVID-19 response.

The XBB strain — an offshoot of the Omicron variant that tore through Maine one year ago — skyrocketed from making up about 34 percent of COVID-19 cases in New England as of Dec. 17 to accounting for nearly 53 percent of cases the following week, according to the U.S. Centers for Disease Control and Prevention..

Nationwide, however, XBB hasn’t spread as far, as the strain made up only 18 percent of COVID-19 cases in the U.S. as of Dec. 24, according to the U.S. CDC.

While each new mutation of the virus becomes more effective at infecting vaccinated people, Jarvis said the latest bi-valent booster was designed to “protect against both the original strains and the Omicron family strains.”

Mainers have the third-highest rate nationally for receiving the booster after Vermont and Washington, D.C. Yet only 27 percent of the state’s population older than 5 has received the latest booster, according to the CDC.

Hospitalizations due to COVID-19 will likely increase in the coming weeks following the holidays, when people have been traveling and gathering while XBB spreads, said Dr. Dora Mills, chief health improvement officer for the Portland-based MaineHealth hospital system.

The shift in dominant COVID-19 variants is a drastic change from only one month ago when the BQ 1 and 1.1 variants accounted for most COVID-19 cases, both regionally and nationwide.

Mills said she hopes COVID-19 eventually becomes endemic with seasonal spikes, much like influenza, but the high level of year-round transmission makes it difficult to tell if COVID-19 is moving in that direction.

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Kathleen O'Brien

Kathleen O'Brien is a reporter covering the Bangor area. Born and raised in Portland, she joined the Bangor Daily News in 2022 after working as a Bath-area reporter at The Times Record. She graduated from...