With schools starting up again, 70 percent of Massachusetts students over the age of 12 have received at least one dose of the COVID-19 vaccine. But youth vaccination rates are much lower in some cities and towns, according to state data released Thursday.

Among large cities, fewer than 45 percent of kids between the ages of 12 and 15 are vaccinated in Fall River, Springfield, Holyoke or New Bedford.

The numbers are slightly better in most of those communities for 16-19 year olds, but are still far below the state average.

By comparison, in Chelsea, which was among the cities hardest hit in the pandemic's early days, 92 percent of kids aged 12-15 have gotten a shot, and more than 95 percent of 16-19 year olds are at least partly vaccinated.

Some smaller towns are also struggling to get their youth vaccinated. In Dartmouth, Wenham and Hardwick fewer than 35 percent of kids aged 16-19 have gotten at least one shot. In Amherst, just 17 percent of kids aged 16 to 19 have gotten a shot. And fewer than 35 percent of kids aged 12-15 have gotten a shot in Orange, Wareham, Hardwick and Winchendon.

The weekly data on vaccination for each city and town in Massachusetts is onlinehere.

In Springfield, the school district is working now to schedule vaccination clinics in middle and high schools. Springfield Superintendent Dan Warwick said he doesn't believe the low numbers stem from a lack of access, since vaccines are now widely available.

Warwick said he believes the low numbers stem from a mistrust of government in his community. Even so, he said, he thinks in-school clinics can be successful.

"The difference is, we have relationships with students and parents," Warwick said. "I think we have that trust, because our staff has worked so closely with the community, really reaching out to the families and I think there's a great deal of relationships and trust that have been established."

And he hopes that's enough for parents to let their kids get vaccinated.

"There's a relationship there," he said. "And that's what we believe is going to make the difference."

In Boston, 65 percent of 12-15 year olds are at least partly vaccinated. Just half of 16-19 year olds have gotten a shot.