Covid-19: low transmission in schools - when strong rules are in place

·2-min read
The risk of transmission at school could be kept low as long as strict measures are applied, says an American study.

Should schools be closed or not? While many countries currently wrestle with this thorny issue as a third wave of the pandemic takes hold, an American study reveals that the risk of transmission in schools could remain low if "appropriate measures" are put in place.

In the US, the question of reopening schools arose at the outset of the pandemic, and by the fall of 2020 most schools had opted for online-only learning, while others opted for a hybrid model with physical and online classes. A team of researchers at the Santa Fe Institute looked at two large schools, spanning elementary and high school, that reopened to students last fall -- to attend classes physically -- to try to learn more about the risk of transmission in schools.

Published in The Journal of School Health , their work suggests that transmission in schools can remain low even when transmission rates are increasing in the surrounding community. However, it's important to note that the spread of covid-19 was in these schools largely due to the adoption of powerful measures including wearing masks, social distancing, ventilation and air filtering.

In terms of the details, both schools regularly tested all students and staff and imposed measures such as wearing masks, social distancing, ventilating rooms, and filtering air. In addition, when positive cases were detected, a tracking system was put in place to minimize the spread. Researchers report that cases were observed throughout the semester, but the transmission rate remained low, at 0.5 or less.

"Because each infection causes less than one additional infection on average, an infection doesn't spread much within the school. If we could get a rate of 0.5 in the community, that would be amazing -- we would be rid of COVID already," explains study co-author Professor Michael Lachmann of the Santa Fe Institute.

The importance of having the necessary resources

An important detail is that the study shows that most of the cases observed were associated with not wearing a mask, and that the risk of transmission was low when the measures were respected. However, the researchers noted two peaks, one at the beginning of the school year and one after the autumn vacations, corresponding to periods during which the children were not in school.

"This study says that if you implement all these measures, including testing, there won't be big outbreaks in schools. But the key here is testing. If you implement all these measures, testing allows you to see when things go wrong," outlines the main author of the study.

However, the survey does not take into account the emergence of new variants, which have been shown to be more contagious according to several scientific studies. It also remains to be seen whether schools have the resources to test on a regular basis, as these two schools did.

Christelle Pellissier