Katie Blair of Cambridge is expecting her first child in September, and planned to get a COVID-19 vaccine toward the end of her pregnancy.

“Infants have poor immune systems and can’t get vaccines early themselves,” Blair said. “I want to be able to provide her with that immunity by getting it personally.”

So Blair, who is the director of an advocacy group called Massachusetts Families for Vaccines, was concerned to hear this week that the federal government is no longer recommending the COVID-19 vaccine for healthy pregnant women and children.

“It’s something that I’ve cared about for a long time, but it is especially personal now that I’m going to have a baby who will have no immunity for the first several months and will be relying on herd immunity from others,” she said.

The decision is alarming to health officials in Massachusetts who say the vaccine is a safe and effective way to prevent serious health problems that COVID-19 can lead to in children and pregnant women. They say it’s not yet clear what impact the government’s decision will have on the availability of vaccines for those, like Blair, who want them. And as local leaders try to plan around those potential gaps, they’re also concerned about how to help parents understand the conflicting advice.

Secretary of Health and Human Services Robert F. Kennedy Jr. signed a directive rescinding the Centers for Disease Control and Prevention’s recommendations for COVID-19 vaccines and ordering the CDC to remove them from the childhood immunization schedule. Kennedy announced the policy change in a video posted to X on Tuesday.

A new vaccine is expected to be released in the fall that will target the variants of the virus that are currently circulating.

It’s not yet determined, though, if the CDC decision will affect insurance companies’ coverage of that new vaccine for children and pregnant women in Massachusetts.

“Our member plans are still reviewing the announcement made by Secretary Kennedy yesterday, as it relates to the COVID-19 vaccine, and are awaiting official guidance from the federal government,” Lora Pellegrini, president and CEO of the Massachusetts Association of Health Plans, said in a written statement. “Once we have reviewed the specifics, we will continue to work with both the federal government and the Commonwealth to ensure compliance with all federal and state guidelines.”

Nearly half of children in Massachusetts are covered by MassHealth, the state’s Medicaid program.

Dr. Robbie Goldstein, commissioner of the Massachusetts Department of Public Health, said the department “will continue to work with insurers, healthcare providers, and others across the state to maintain access to evidence-based, safe vaccines.”

Boston Commissioner of Public Health Dr. Bisola Ojikutu said the commission “strongly disagrees” with the government’s decision. Moreover, she said Kennedy’s announcement spread misinformation about the vaccines, including their safety and efficacy.

“Based on the data that we have, we will continue to recommend that everyone ages 6 months or older should get an updated COVID-19 vaccine,” she said. “COVID-19 vaccines remain safe and have really undergone some of the most intense safety monitoring in our country’s history.”

Ojikutu said she’s particularly worried about the impact that losing access to vaccines could have on pregnant women.

“We know that [COVID-19 infection] is associated with increased risk of adverse pregnancy outcomes like preterm birth, hypertensive disorders in pregnancy like preeclampsia, postpartum hemorrhage and actual maternal mortality,” Ojikutu said. “So this is a significant issue and we are very concerned about the higher risk that pregnant individuals experience.”

And if those mothers can’t get vaccinated, it can be dangerous for their newborns, said Dr. Brenda Anders Pring, a Boston pediatrician and president of the Massachusetts Chapter of the American Academy of Pediatrics.

“There are a whole bunch of unimmunized babies that are about to be born in Massachusetts — 70,000 babies a year — that will have no protection whatsoever,” Anders Pring said.

She said that is a particular concern in the fall and winter, when we typically see an increase in COVID-19 cases. Young children won’t have immune systems capable of fighting off illness or underlying immunity. Anders Pring said she’s also concerned about older children losing access to the vaccine.

“I think that we have to worry about herd immunity,” she said. “I have a 7-year-old patient who has a very serious disease and she’s on immunosuppression for it. So she is always at risk for picking up really bad illnesses, including COVID-19. And now I’m wondering if her sister who lives in the household, who is 13, if she’s going to be able to get the COVID vaccine like she does every year. And so that’s a very real problem for that family and for many other families.”

The announcement is confusing to parents, Anders Pring said.

“So there’s some that are not going to know what to do, and they just want to do what’s best for their children, but they’re getting misinformation, disinformation, and it’s not even coming from scientists or experts in pediatrics or infectious disease,” she said.

Ojikutu said if vaccine availability becomes more limited, the Boston Public Health Commission will try to “fill the gaps.”

“We had planned on having a back-to-school vaccination event where we would not only talk about COVID-19 vaccination but other vaccinations, because we know that there is misinformation that’s circulating,” Ojikutu said. “We had planned on doing that anyway, and we will make sure to make that event as large as possible.”

She acknowledged, though, that it’s not yet clear if the city will have access to the updated COVID-19 vaccine for that drive.