As coronavirus cases continue to rise in Massachusetts, young people account for an increasing share of new infections, adding urgency to the race to vaccinate all age groups fast enough to curb the virus’s spread.
This week, for the first time, state public health officials released a detailed breakdown of COVID cases among the 0-19 age group, which had the largest number of cases in the two-week period that ended April 3. The data coincided with a record-high weekly report of coronavirus cases among students in Massachusetts public schools, collaboratives, and special education programs.
But officials and experts emphasize that in-school transmission remains rare.
“Schools have done a really good job of keeping people safe, of reducing transmission,” said Dr. David Rosman, president of the Massachusetts Medical Society. “The tradeoff for schools is a tradeoff worth taking.”
From March 21 through April 3, 2,748 teens ages 15-19 tested positive for the coronavirus, the most for any group under 20, according to new state data. The fewest cases occurred in children ages 4 and under: 1,116 for the two-week period. Overall, the state reported 6,982 cases of COVID among those 19 and under during that period.
A substantial number of cases statewide also occurred in the 20-29 age group, with 6,375 cases over the two-week period, followed by residents ages 30-39, with 4,221 positive cases.
Case numbers among older residents have fallen in recent weeks as more people have the opportunity to get vaccinated against the virus. Eligibility expanded to residents ages 55 and older on Monday, as well as to people with one qualifying health condition.
“We know that cases now are trending younger, and that’s because people are getting vaccinated and the vaccines work,” said Rosman.
As of Friday, 1,676,961 people in Massachusetts have been fully vaccinated. That includes more than 344,000 residents who are 75 years or older, and more than 384,000 people who are 65 to 74 years old.
The rest of Massachusetts’ adult population will be eligible to book vaccine appointments starting April 19. Vaccines are not yet approved for children and young teenagers under 16, though Pfizer and its partner BioNTech SE plan to ask the US Food and Drug Administration for emergency use authorization of its coronavirus vaccine in teenagers ages 12 to 15. Moderna and Pfizer have also both started testing their vaccines in children under 12.
The rise of coronavirus variants in the United States is a concern for some public health experts, who say the variants can be more infectious and could be partially to blame for cases rising statewide. Rosman said he’s seen more young people “ending up in the hospital than we would have expected with the initial coronavirus.”
The rising case numbers among Massachusetts’ youngest population comes just as the vast majority of elementary schools statewide have sent students back to in-person learning full-time. The return was mandated by the state as part of a larger effort to get students back in traditional learning environments before the end of the academic year. Middle schools are set to return later this month; a date has not been set for high schoolers to return full-time.
Weekly reports of coronavirus cases among students in Massachusetts public schools, collaboratives, and special education programs hit a record-high for the week that ended Wednesday. Cases among staff members, however, dropped this past week, likely as more had the opportunity to get vaccinated.
State education officials do not break down coronavirus cases by age group or school level in their weekly reports.
State officials have said the rise in cases in schools is due to a number of factors, and community spread is only one of them.
The student population has grown from an estimated 450,000 students in some form of in-person learning during most of the year to about 610,000 students in person as of Wednesday, according to state officials. That rising population, combined with the frequency of pool testing in more than 1,000 Massachusetts schools, has led to the detection of more cases inside school buildings.
From March 7 to April 3, 25 new clusters were identified in K-12 schools, according to weekly data from the state Department of Public Health, though a cluster of cases in a single classroom does not mean those students contracted the virus in school.
“As cases increase in the community, we expect that cases identified in schools will also increase,” Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said during a briefing on Friday. “This is not necessarily indicative of school-based transmission.”
Most cases are coming from out-of-school events, such as family gatherings, after-school activities, and sports games, said Russell Johnston, senior associate commissioner at the Massachusetts Department of Elementary and Secondary Education.
“The school numbers going up does not mean that schools are not safe,” he told the Globe earlier this month. “In fact, schools are very safe.”
Ryan Huddle of the Globe Staff contributed to this report.