The coronavirus variant has officially arrived in Mass. Here’s what you should know

Drive-through testing earlier this month in RandolphCraig F. Walker/Globe Staff

A new coronavirus variant has officially arrived in Massachusetts, public health officials said over the weekend. The news raised fears that the state, which saw its pandemic surge in the fall, could face even more illnesses and deaths in the months ahead.

Here’s what you need to know.

What is the variant?

The variant is a mutation of the coronavirus. It emerged in the United Kingdom and has since been detected in numerous countries around the world, including the United States and Canada. Scientists say there’s nothing new about a virus mutating. Viruses constantly mutate naturally as they replicate and circulate in their hosts. In the UK variant case, the result appears to have been a virus that is more transmissible but doesn’t cause more severe disease.

How many cases have there been in Massachusetts?

So far, there has officially been one case. The Massachusetts Department of Public Health announced Sunday that the first case had been detected in the state. The department said the person who contracted the variant was a Boston woman in her 20s who had traveled to the United Kingdom and became ill the day after she returned. The Boston Public Health Commission issued a statement saying the woman “returned to Boston on January 3, 2021 and had a brief (approximately 2 hour) layover at Logan International Airport before traveling to another state.”

“Given the increased transmissibility of this variant and the number of states and other countries that have found infected cases, the Department expected the variant to arrive in Massachusetts eventually,” the DPH said. Governor Charlie Baker said two weeks ago there was no reason not to believe the variant was already in the state.

Why should I be concerned about one case?

Experts and officials believe it could well be the beginning of a tsunami of cases. “The key issue is that the variant does look more transmissible, and in Britain it rapidly became the dominant strain — they saw it rapidly increasing over time,” Dr. Paul Sax, clinical director of the Division of Infectious Diseases at Brigham and Women’s Hospital, said in an e-mail.

The new variant is “definitely more contagious, spreading more easily from one person to another than the previous version of the virus. What that means is because the new variant spreads more rapidly through the population than the old variant, it will soon become the predominant form of the virus in the population. It’s going to beat out the other one,” Dr. Philip Landrigan, who directs Boston College’s Program for Global Public Health and the Common Good, said Tuesday.

The US Centers for Disease Control and Prevention warned Friday of the possibility of another surge of cases and deaths due to the variant. The agency said its modeling suggested it was possible that the variant would become the predominant source of all infections in the United States by March.

“I want to stress that we are deeply concerned that this strain is more transmissible and can accelerate outbreaks in the US in the coming weeks,” said Dr. Jay Butler, deputy director for infectious diseases at the CDC. “We’re sounding the alarm and urging people to realize the pandemic is not over and in no way is it time to throw in the towel.”

What is the problem with increased transmissibility?

The experts say the new variant does not cause more severe illness, which is welcome news. But the problem is that if the disease spreads to a much larger number of people, a larger number of people will become hospitalized and die.

“We shouldn’t be lulled into complacency and say, `Well, maybe it’s more transmissible, but it isn’t a more serious disease.’ Well, the more people that get infected, quantitatively, the more people that are going to get hospitalized. And quantitatively, the more people that get hospitalized, the more people are going to be seriously ill and die,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Tuesday.

“The more people you get infected, the more serious situation you’re going to be in,” Fauci, who has been tapped to serve as chief medical adviser in the Biden administration, said in an interview with Harvard Business Review that was livestreamed as part of the HBR Now series.

What can we do about it?

Experts and officials say that the variant can be stopped by the same precautionary measures that people are already taking. “The same things we do to prevent covid19 now should apply to this variant — distancing, avoiding crowds, masks in public spaces,” said Sax.

“Once it’s here, it’s going to spread,” said Landrigan. “Everybody’s got to keep their guard up. Everybody’s got to double down on what they’re doing. ...People are going to have to be even more conscientious about doing those things.”

Landrigan said state officials should also carefully monitor whether bars, restaurants, and public gatherings are adding the spread of the virus.

“Concerns that the new variant could further exacerbate the pandemic in upcoming weeks should drive everyone to double down on prevention. That includes continued social distancing, mask wearing, avoiding crowds and getting ready for the vaccine when it is your turn to do so,” Dr. Howard Koh, a professor at the Harvard T.H. Chan School of Public Health and a former top Obama administration public health official, said in an e-mail.

Will vaccines stop the virus?

Vaccines are another key way to stop the spread of the virus, but so far the rollout has been slow in Massachusetts.

The vaccines appear as of now appear to protect against the variant so it’s “important that we increase the supply and distribution as quickly as possible,” said Sax.

Dr. Ashish Jha, dean of the Brown University School of Public Health, told the Globe last week, “There is every reason to believe [the variant] is going to cause a huge spike in cases.”

“If we can start vaccinating people in a serious way,” Jha said, “that will blunt things a lot.”

No one in public health is looking at the data and saying, “Oh, thank God,” Jha told the Globe. “We’re looking at the next four to six weeks and thinking, ‘Please, please, get the vaccine into people.’ We are in for such a hard six to eight weeks.”

Could there be more trouble ahead from other mutations?

Scientists say the UK variant may not be the only problem variant to emerge. Other mutations are now rapidly popping up, including two notable variants already detected in South Africa and Brazil. The longer it takes to vaccinate people, the more likely it is that a variant could emerge that can elude current tests, treatments, and vaccines, The Associated Press reported.

“We need to do everything we can now ... to get transmission as low as we possibly can,” Dr. Michael Mina, an epidemiology professor at the Harvard T.H. Chan School of Public Health, told the wire service. “The best way to prevent mutant strains from emerging is to slow transmission.”

“We’re in a race against time” because the virus “may stumble upon a mutation” that makes it more dangerous, said Dr. Pardis Sabeti, an evolutionary biologist at the Broad Institute of MIT and Harvard.

Material from Globe wire services and prior Globe stories was used in this report.