COVID-19 infections declined in Marin as schools in the county reopened for in-person learning last year, according to a new study.
The study, published last month in the peer-reviewed national medical journal Cureus, tracked attendance at 77 transitional kindergarten through eighth-grade Marin schools from Sept. 8, 2020, to Jan. 21.
Researchers found a correlation between having more students in class in person and lower COVID-19 rates in the community. That was in contrast to school breaks — such as Halloween and holiday time off in December — when cases spiked, said study co-author Dr. Michaela George, an epidemiologist and assistant professor at Dominican University of California in San Rafael.
“It shows that when schools follow the advice of their local public health officials and there is a good collaboration with local educators, kids can stay safe in the classroom,” George said.
Marin County spokesperson Laine Hendricks said the study results show the value of a detailed, data-driven school safety program that is coordinated between different education and health agencies.
“It documents — from an epidemiological standpoint — how our local schools’ strict adherence to public health policies helped keep the COVID-19 incidence rate low, while helping Marin become one of the first counties in the state to achieve a 100% reopening rate,” Hendricks said in an email.
The article, published Nov. 22, also pointed out how the strong collaboration with Marin County Office of Education was key to the success of reopening schools — even during the pre-vaccine period when the only virus safety tools available were masks, social distancing, disinfection and hand-washing.
“The increasing percentage of students returning to in-person school did not drive an increased COVID-19 case rate in the community,” the study said. “On the contrary, this analysis revealed that there was a drop in countywide COVID-19 cases as the phased student return percentage increased.”
Over the 21-week observational period involving 17,639 students, 4,938 school staff, and 899,175 student days, the countywide COVID-19 rate decreased from 89.9 to 35.89 per 10,000, as more students returned to in-person learning, the report stated.
“The schools’ strict adherence to public health guidance and site-specific safety plans against COVID-19 yielded a significantly reduced incidence rate of 0.84% among in-person learning participants,” the study said. “Only nine cases were traced to suspected in-school SARS-CoV-2 transmission by way of rigorous contact tracing. The countywide COVID-19 incidence rate was 2.09%.”
The study specifically cited the close collaboration between Marin County Office of Education and the public health team in the county’s Health and Human Services Department. That included, for example, a 30-point school site specific protection plan, which each school was required to complete in order to resume in-person classes.
George said the study does not claim a causal relationship between reopening schools and lower case counts — but it does show a correlation.
“For example, over the Thanksgiving holiday school break, spanning the period from November 23, 2020, to November 29, 2020, and the two-week winter holiday school break, from December 21, 2020, to January 3, 2021, countywide COVID-19 cases increased in the absence of in-person learning participants at the school sites,” the study stated. “This observed trend could have been confounded by the increased travels, social gatherings, and mixing of different households.”
Hendricks said a county intern, Shayne Paff, was one of the study co-authors, along with a half-dozen or so members of Marin’s epidemiology and public health teams. Paff has since joined the virus response team in Sonoma County, she said.
Besides Paff and George, other co-authors were Dr. Matt Willis, the Marin public health officer; Dr. Lisa Santora, the deputy public health officer; and county staffers Rochelle Ereman, Alana McGrath, Bethany Dominik, Karina Arambula, Jasmine Soriano and Charis Baz.
