Rising coronavirus cases among students and staff members don’t mean schools are unsafe, officials and health experts say

With coronavirus case counts steadily rising in Massachusetts, numbers have been similarly growing among public school students and staff members, on Thursday reaching the highest weekly totals since the start of the academic year.

The record-breaking report — 801 new coronavirus cases among students and 244 among school staffers for the week that ended Wednesday — came just days before elementary students across the state are set to return to full-time, in-person learning.

But state officials and many public health experts said Friday that though the rise in cases may be alarming for families, the numbers shouldn’t be seen as an indication that schools are unsafe.

“Whenever you see rising cases in the community, you see rising cases in kids, so because you see school-age kids getting infected, that doesn’t mean they acquired it in school,” said Todd Ellerin, director of infectious diseases at South Shore Health.

Massachusetts has been seeing an increase in virus cases among young people across the state in recent weeks, particularly in those under 30. One reason cases are rising in public schools, educational collaboratives, and special education programs: The public school population is a part of that young group that has experienced an increase in cases.

There are also other factors at play. For one thing, there were more children and staff members in schools last week than at any time since schools shut down in March 2020. Officials estimated that about 575,000 students across the state were attending some form of in-person learning for the week ending Wednesday, and about 85,000 staff members were working in buildings — up from an estimated 450,000 students and 75,000 staff members for most of the school year.

That number is expected to rise again next week, meaning the number of coronavirus cases reported next week could rise, too, but the increase could be proportional to the state’s in-person population.

“What I would want parents to do is just to put it into that broader context,” 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. In fact, schools are very safe.”

Another potential explanation for the rise in cases: The state’s pool testing program — a faster and more cost-effective testing technique that bundles coronavirus tests — has been operating in hundreds of schools since the end of February.

More than 1,000 schools are now participating in the pool testing program, which is free of charge for districts until the end of the academic year. Since the launch of the program, just 172 people have tested positive.

“The more testing you do, the more likely you are going to be to identify cases,” said Davidson H. Hamer, a professor of global health at Boston University. Some asymptomatic cases are being identified now that may have previously gone undetected.

The number of new school clusters — defined by state public health officials as “two or more confirmed Massachusetts cases with a common exposure” — has also been rising steadily for the past month. Clusters are reported in four-week periods in the state Department of Public Health’s weekly public health report.

Between Feb. 28 and March 27, the state had identified 25 new clusters in K-12 schools, which includes boarding schools, public schools, private schools, and special education schools. For the four-week period prior to that, Jan. 31 to Feb. 27, only five clusters in K-12 schools had been identified.

Most recently, Tyngsborough Elementary School returned temporarily to remote learning this past week after suspected in-school transmission that led to a cluster of positive cases, superintendent Michael Flanagan told the district. The school is set to return to full-time, in-person learning on Monday.

Clusters, however, are not direct indications of in-school transmission, which state officials have said is very limited. Coronavirus transmission among public school children is largely happening outside of the classroom at family events, after-school activities, and sports games, said Johnston.

“On a very minimal basis have we seen where there’s been any type of transmission from inside a school building. The contact tracing really helps us to see that it’s happening elsewhere,” Johnston said.

The important part is that when cases are identified, the people infected are isolated to keep the virus from spreading in school buildings, Johnston said.

Ninety percent of school districts are set to send elementary school students back to full-time, in-person learning on Monday. Other districts, including Boston and Worcester, have received waivers from the state to return to in-person learning in the weeks to come; all elementary schools are expected to be fully in person by May 3, according to state education officials.

Both state officials and the Centers for Disease Control and Prevention have said in-person school is safe for children, as long as mitigation measures are followed, including 3 feet of distance between students and universal mask wearing.

The coronavirus also continues to be significantly less severe for young, healthy children, Ellerin said. As long as the coronavirus variants don’t begin to cause widespread hospitalizations or deaths among children — which they have not — schools should be safe to remain open, he said.

“My prediction is that schools are going to go forward and not shut down. I think we’re going to be able to handle this,” Ellerin said. “I think we’ve already been in worse places than we’re going to be.”