PROVIDENCE, R.I. (WPRI) – A recent U.S. Centers for Disease Control and Prevention study showed that improved ventilation in schools may reduce COVID-19 infections by nearly 50%, and Target 12 has learned most Rhode Island school districts have invested in ventilation technology.

The CDC published a large-scale study of COVID transmission in May, looking at 123 Georgia elementary schools comprising 66,499 students. The study was conducted between Nov. 16 and Dec. 11, 2020.

The study found schools that improved classroom dilution, such as by opening windows and doors, reduced COVID infections by 35%. Schools that improved dilution by adding high-efficiency particulate absorbing (HEPA) filters or ultraviolet germicidal irradiation (UVGI) reduced infections by 48%.

“I would say that research is absolutely correct,” said Peter Sanchioni, superintendent of Tiverton Public Schools.

He told Target 12 that district leaders started purchasing filtration devices at the beginning of the pandemic.

Heading into this school year, Sanchioni said each of the district’s five schools have HEPA filters in the heating and cooling units, and each classroom has individual filters. The district also has three UVGI units.

He said about 20% of the district’s roughly 1,600 students chose distance learning for the entirety of last year. But from mid-October through the end of the year, everyone else was in-person.

“We had 144 students catch COVID,” Sanchioni said. “Not one of them caught it in our schools. Not one of them transmitted in our schools.”

Target 12 asked every school district in Rhode Island about its ventilation systems. Of the 24 school districts that responded, 23 said they have HEPA filters in their buildings, while only three — including Tiverton — have UVGI units.

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Craig Levis, superintendent of Coventry Public Schools, said it’s no secret that his district has old buildings. He said that’s why district leaders brought in an expert to evaluate airflow problems in the fall of 2020.

“We recognized the importance of air quality,” he said. “I think we attacked it from a global perspective.”

Levis said the district now has roughly 150 portable HEPA filters.

David Weber, a professor of epidemiology at the University of Chapel Hill, told Target 12 that while the findings of the research are encouraging, the study doesn’t meet the standards of a randomized clinical trial.

“We need solid evidence that they would actually lower infections,” Weber said. “I am not aware of any clinical trial that’s actually proved that by doing this you actually do prevent infections.”

Weber used the analogy of slices of swiss cheese: if COVID-19 gets through one layer of protection, like ventilation, masks can provide another layer of protection. And if the virus gets past that, vaccinations might stop it, and so on.

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“All of these preventative mitigation strategies are additive or synergistic together, and we should do all of them,” Weber said.

The study concludes that HEPA filters and UVGI units are especially important in rooms with “an increased likelihood of being occupied by persons with COVID-19,” such as the school nurse’s office.

Tolly Taylor ( is a Target 12 investigative reporter for 12 News. Connect with him on Twitter and on Facebook