MONTREAL -- Everyone seems to agree that Montreal’s second wave isn’t looking good lately, but what exactly is driving it? That depends on who you talk to -- even doctors disagree.

Schools are to blame, argues Dr. Earl Rubin, a pediatric infectious disease specialist.

“There's been 8,000 cases within schools, of which 80 percent are students and 20 percent are teachers,” said Rubin.

“That's a huge number.”

Compared with the city’s first wave, Rubin added, three times as many school-aged kids are now catching the virus.

But not everyone is convinced that schools are the primary source of all the current COVID-19 spread.

Dr. Caroline Quach, a doctor based at Ste-Justine hospital who specializes in infection prevention and control, says school COVID-19 cases are an effect, not a cause.

“There is transmission in schools,” she said. “But to me, schools are not the culprit of the second wave—schools are a reflection of the second wave.”

The competing theories tend to come down to details in school transmission, some of which aren’t fully understood, like poor school ventilation and how much that could be contributing.

Dr. Rubin says the timing checks out to see the start of school as the beginning of a major cycle of infections.

“Schools opened early September,” he said. “By the end of the month our numbers were up, and we were in that 14-to-28-day period.”

Dr. Quach points out that several other things happened around—but not exactly in—the same timespan.

There was increased socializing in the weeks right before schools reopened, she says, as the economy increasingly reopened and people relaxed.

She believes, therefore, that the second wave started before schools reopened.

“I think it was the increase in social interactions,” she said.

But “looking for a culprit, I think, may not even be what we should aim to do,” she said—it’s eliminating the spread.