Concerns over control of school outbreaks

More frequent rapid testing in schools is possible until vaccines for children take hold

COVID-19 outbreaks in Ontario elementary schools have reached a high since the beginning of the school year, with more than 160 current outbreaks, almost double the number from two weeks ago and almost triple the total from a month ago.

Scientists and doctors say that community vaccination rates, masking and ventilation upgrades in classrooms have played a role in helping to keep cases in schools from rising even higher, but they warn that outbreaks could very well continue to climb with the cold weather — even with Thursday’s launch of COVID vaccine clinics for children five to 11.

That’s because with the recommended eight-week interval between the two pediatric doses, it will take more than two months for the first group of kids who receive a shot to be considered fully vaccinated. For example, children who receive their first shot in late November won’t complete their vaccine series until February.

And that means there’s still plenty of time for the virus to continue to spread in schools among students.

Already, classes and students have been sent home in Toronto for exposure to the virus, not necessarily because of a certified outbreak. Sixteen schools are currently closed in the province. And in the two weeks leading up to Wednesday, there were 1,460 cases in children between the ages of five and 11. That works out to a rate of 135.4 cases per 100,000, the highest rate — by a long shot — of any age group in Ontario. The next highest rate was 60.8 per 100,000 in the 20-39 age group.

“This is very different from early in the pandemic, especially when schools were closed, when a tiny proportion of cases were among kids,” said Dr. Anne Wormsbecker, a Toronto pediatrician. “Fortunately those cases with children rarely require hospitalization and even more rarely require ICU admission. But at the same time we know anytime one person is sick, they can make someone else sick.”

Early indications from studies are children may derive strong protection from one dose.

So what are we to do before enough kids between five and 11 get vaccinated? More frequent rapid testing in more schools, say experts.

“You won’t catch every case, but you’ll catch a bunch of them. You’ll really tamp it down if you do that,” said Colin Furness, an infection control epidemiologist at the University of Toronto. “We should have had a plan in place for (widespread testing) given that we know that we’re basically herding COVID into primary schools.”

Ontario launched a testing program late last month in which students showing COVID symptoms and those identified as being close contacts of a confirmed case can get a PCR test kit from school to take home, collect a specimen and then drop it off in their community for testing. But the program essentially targets situations in which COVID has either already been detected or students have symptoms.

The province also announced a rapid antigen test program to be used at the discretion of local public health units as an additional screening layer in situations where cases have already been identified or there is high transmission in the community. Rapid antigen tests are not diagnostic but they can help public health units get a sense of spread; those who test positive on rapid tests are asked to get a PCR test for confirmation.

Dr. Peter Juni, an epidemiologist and scientific director of Ontario’s COVID-19 Science Advisory Table, says rapid tests would be a good tool to help interrupt the chain of transmission among elementary students in areas experiencing moderate and high numbers of cases. Rapid tests could be offered once a week where cases are 50 per million people per day, and twice a week in areas where daily cases approach 150 to 200 cases per million.

“The idea is to just get the tests into circulation, have families use them and contribute to reduce the transmission risk,” he said. “It would basically give us the possibility to send those students who are positive home before they have the opportunity to spread the virus to others in the school, provided that a positive antigen test will be confirmed by a PCR test.”