PREPARING TO CATCH A WAVE

Advisory table head warns Ontarians: Wastewater indicator, positive tests point to case growth

Signs are emerging that point to the beginnings of a summer wave of COVID-19 in Ontario, the head of the province’s science advisory table is warning.

Dr. Fahad Razak, scientific director of the science table, points to a rising COVID wastewater signal, increasing test positivity and a surge of public health units experiencing exponential growth in cases.

There has been a gradual increase in the provincewide wastewater signal since the beginning of June along with test positivity that has been going up for the past three to four weeks. Then there’s the fact, he says, that about 40 per cent of public health units now have a reproduction number greater than one — all amounting to evidence the province has entered another wave.

“Putting all of this together, I think we’re seeing the beginning of a wave,” Razak said. “But it does not look like it has the intensity in terms of amplitude or pace of what we saw with the start of the Omicron wave. How fast it will rise and what the peak will be are unclear.

“Based on everything that we’re seeing, both in Ontario and globally, this is likely to be a less severe wave than what we’ve experienced in the past with less direct pressure on the health-care system.”

Razak’s red flag comes as the National Advisory Committee on Immunization recommended this week that additional boosters be given to a larger portion of the population in the fall. Other regions are also seeing a rise in hospitalizations driven by Omicron subvariants, including Quebec, which recently experienced a surge in community transmission and cases in healthcare workers.

Meanwhile, the World Health Organization reports that infections are growing in 110 countries driven by the BA.4 and BA.5 subvariants, resulting in an overall 20 per cent increase in global cases.

Several infectious disease experts say fourth doses should be offered to all residents now ahead of a possible fall wave, while others say only those who are deemed at higher risk should be getting a second booster.

“If you’re someone who is higherrisk or is in a situation where you’re being exposed to a lot because you’re on TTC twice a day, in and out of work or something like that, it would be very reasonable to go and get that fourth shot now,” Razak said. “On the other hand, if you are otherwise low-risk and you have very little day-to-day exposure, it is reasonable to wait to get that booster dose until you’re closer to the fall or there’s more concretely a rise happening.”

At a press conference Thursday, Dr. Theresa Tam, Canada’s chief public health officer, said up-todate vaccinations are the “foundation of our protection” and that those who had two doses and a booster shot had hospitalization rates that were five times lower than unvaccinated people during the Omicron wave in April and May.

She also reiterated NACI’s recommendations that those at risk of severe illness receive a fourth shot now, as boosters “increase protection by activating your immune response to restore protection that may have decreased over time.”

Dr. Gerald Evans, the chair of the division of infectious diseases at Queen’s University, said it’s uncertain whether fourth doses will be effective enough against BA.4 and BA.5 for the larger population. Those subvariants have an alteration within its genomes, making it more difficult for antibodies to bind to the spike proteins, which in turn makes these variants more likely to have immune-evading properties, he explained.

Pfizer and Moderna are developing vaccines that will specifically target Omicron, known as bivalent vaccines, which will likely be available in the fall. Both companies say they’ve tested their vaccines and they appear to be highly effective against Omicron, and plan to submit their data to governments in the next few months.

“I do totally agree that we should be rolling out boosters in the fall,” said Evans. He predicts a wave will occur in the late fall or early winter, and another will follow in the late winter or early spring because that’s how the COVID-19 virus has behaved previously, similar to other illnesses in the coronavirus category, he said.

NACI also announced in a release Wednesday that everyone aged 12 to 65 may be offered another dose in the fall, regardless of the number of previous doses, but that recommendation is “discretionary” and not categorized as a strong recommendation.

Those groups include all residents over 65; people 12 and older who have underlying medical conditions; Indigenous adults; racialized and marginalized communities that have been harder hit by the virus throughout the pandemic; migrant workers; residents of shelters, correctional facilities and group homes.

Recommendations will be provided on the type of COVID-19 booster dose that should be offered as evidence emerges on bivalent vaccines.

NACI said in its press release that “cases of COVID-19, including associated hospitalizations and deaths, are currently declining in Canada. However, the likelihood, timing, and severity of a future wave of COVID-19 is uncertain.”

Colin Furness, an infection control epidemiologist at the University of Toronto, said he is afraid the increasing signals Ontario is experiencing could mean we are approaching endemicity.

“My belief is that when we took masks off on the TTC, we started to harmonize different wastewater signals across the GTA. In other words, mixing people together on the TTC is not going to cause the signal at one wastewater treatment plant to go down, it’s going to cause the other ones to come up to match,” he said.

“If you think about that logically, that kind of synchronization, that’s a path to endemicity. Not a wave that comes and then subsides, but a new normal where the line is flat but it is at a very elevated level.”

He added that the elevations in wastewater signals, as well as cases in public health units, reflect the dropping of mask mandates earlier this month.

“But it’s not just that. It’s the mindset that goes with it. We see more and more people who ought to know better engaging in crazy, risky behaviour,” Furness said. “If I can be on the TTC and I don’t need to have a mask, then I can go out to dinner because that’s obviously less dangerous and if that’s the case, I can definitely go see a movie.

“It’s causing self-destructive logic to take hold.”