MASSACHUSETTS HAS some of the highest numbers of COVID-19 variants of any state in the country. Some of the variants that exist today are more contagious and may cause more severe disease than the initial virus. Some may also be able to break through the vaccines that are currently available. And, experts agree, more variants are coming.

So what does this mean for Massachusetts residents, and for decisions on whether to reopen schools, whether to get vaccinated, and what precautions to take?

The Legislature’s Joint Committee on Public Health and Joint Committee on COVID-19 and Emergency Preparedness and Management held a hearing Tuesday where it heard from seven medical and public health experts about the variants and their implications. Here are a few takeaways from the three-hour hearing.

What exactly are the variants?

As viruses transmit, they naturally mutate into different forms, sometimes with characteristics that make them more dangerous. For now, there are four or five variants of concern identified in the US.

B.1.1.7, a strain first identified in the United Kingdom in the fall of 2020, accounts for 44 percent of the variants present in the US and may account for around half of new transmissions in Massachusetts. Dr. William Hanage, associate professor of epidemiology at Harvard’s School of Public Health, said this strain is about 50 percent more transmissible than the previous virus, and causes more severe disease, with mortality rates thought to be 30 to 60 percent higher. The existing vaccines do offer protection from this variant. There are around 1,100 cases of B.1.1.7 in Massachusetts

B.1351, a variant first identified in South Africa, is thought to be able to break through prior immunity from infections and possibly from vaccines. It appears to be well-controlled with precautions like masks and distancing and has not spread widely in the US. There are 12 cases identified in Massachusetts.

The P.1 variant that was first detected in Brazil and led to a major surge there, appears to be spreading at low levels in the US. Massachusetts has the most cases in the country, with 102.

Other variants have begun to emerge in California and New York.

“We can expect variants to continue to emerge because that’s the way infections work,” Hanage said. Hanage said the best way to stop variants from developing is to prevent new infections, which reinforces the importance of vaccinations. Each infection, he said, is like “buying the virus a lottery ticket,” and if the virus wins, it will evolve.

Paul Biddinger, chief of emergency preparedness at Mass General Hospital, said his biggest concern is what new variants will develop and what their characteristics will be in terms of transmissibility and morbidity. Biddinger said the surprises that have occurred during COVID so far have taught scientists to be “humble about rethinking what we know and what we do” and to be nimble and “willing to change course when the data tells us to change course.”

There remain a lot of unanswered questions about the variants, such as whether the danger of asymptomatic spread is different than with the initial virus.

Are existing vaccines effective against the variants?

There is not enough data to answer that questions. The South African variant has shown that it can at least partially evade antibodies from natural infections and vaccines.

The Moderna and Pfizer vaccines were tested before the variants existed. There have been a large number of cases of B.1351, the South African variant, “breaking through” the vaccine’s protection and infecting individuals in Israel, which used the Pfizer vaccine, suggesting a lower level of efficacy for the variant.

The Johnson & Johnson vaccine was tested when B.1351 and the Brazilian P.2 were prevalent, and was more than 80 percent effective in preventing severe disease from both of those, and more than 60 percent effective in preventing moderate disease. The US government temporarily paused the use of the Johnson & Johnson vaccine amid concerns about rare blood clots. The AstraZeneca and Novavax vaccines, neither of which have been approved in the US, have low levels of effectiveness against those variants.

“Currently, it’s really a race between the vaccines versus variants,” said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center.

Barouch said it’s unclear whether a vaccinated individual who gets a COVID variant would have a less severe illness and whether they would be less likely to transmit it.

Dr. Nahid Bhadelia, an infectious disease physician at Boston University School of Medicine, said preliminary data show that if a vaccinated person gets infected, they have less virus in their airwaves so they are less likely to transmit it.

Barouch and other experts raised the possibility that booster shots may eventually be needed to boost immunity against virus variants. Barouch said there is the precedent of influenza, which requires an annual shot. “Let’s hope we don’t need to do that. Vaccinating the world is a very big task,” he said.

Biddinger said he thinks there is a “decent likelihood” boosters will be needed, which would require the state to invest in a more sustainable vaccination strategy.

Do we know how prevalent the variants are?

Probably not. The United States lags behind many other countries in genomic sequencing, which involves testing samples that were collected from COVID patients and looking for minor differences in the genetic materials that make up the virus to identify variants.

Dr. Bronwyn MacInnis, director of pathogen genomic surveillance at the Broad Institute, said genomic sequencing is important for surveillance purposes – to determine which variants are out there – and for epidemiological purposes, to shape public health responses by helping detect transmission patterns, identify outbreaks, and conduct contact tracing.

MacInnis said to confidently determine how prevalent the variants are, the US should be sequencing around 5 percent of cases. Currently, Massachusetts is sequencing 1.4 percent, slightly higher than the national rate of 1.1 percent. The Broad Institute is doing 41 percent of the sequencing here, the Department of Public Health is doing 15 percent, and the rest is being done by private and academic labs.

Are there differences in treatment for the COVID-19 variants?

Dr. Nahid Bhadelia, an infectious disease physician at Boston University School of Medicine, said some general therapies, like steroids, are likely to treat the variants the same as the initial virus. There is no data on the use of anti-viral medications like remdesivir on variants, but it is likely to be effective.

Bhadelia said the bigger concern is with the use of monoclonal antibodies – products like Regeneron’s antibody cocktail – which are less likely to be effective on viruses that can evade the body’s immune response. These products today are used in high-risk patients early on in the disease.

What does the rise of variants mean for school reopenings?

Dr. Benjamin Linas, associate professor at Boston University’s School of Medicine who has been advising Brookline public schools, said studies have shown in-school COVID spread to be low with mitigation measures, including masking, three to six-foot distancing, hand sanitizing, and ventilation measures like opening doors and windows. He said variants often spread infection faster, but the basic strategies for minimizing exposure are the same. “The variants are not a new virus. The variants are not a new pandemic,” he said.

Linus urged lawmakers to reconsider the framework of weighing COVID safety against in-person learning. Massachusetts instead is in the middle of a “pediatric public health crisis” with massive increases in demand for psychiatric care. Students are also experiencing significant learning loss.

The real tradeoff, Linus said, is the risk of a tmental health and education crisis balanced against the risks of in-person learning. “Unfortunately, we’re in a pandemic. The concept of ‘safe’ is a myth,” Linus said.

For him, Linus said, the answer is clear. “Although the variant remains of concern, I don’t think that rises to the level we should accept the mental health crisis out of fear for COVID risk,” he said.

What are next steps?

State Rep. William Driscoll, a Milton Democrat who chairs the COVID-19 emergency preparedness committee, said in an interview after the hearing that he wants to look into what state and federal support would be necessary to improve Massachusetts’ performance in genomic sequencing. He wants to understand how an increase in sequencing could interact with other interventions like rapid testing. “Where best to invest is the question in my mind,” Driscoll said.

Driscoll wants to see the Baker administration actively thinking about ideas like delaying the second dose, should federal authorities approve it, or sending doses to communities hit hard with variant outbreaks, like Cape Cod.

Driscoll also said he wants to find a way to discuss the variants publicly with “simple and effective messaging,” so people do not have to weed through a list of mutations with technical names.