Ottawa residents should expect a rare summer wave of COVID-19 as more infectious and more elusive Omicron subvariants become dominant in the city, according to the wastewater project’s co-principal investigator.
Tyson Graber, associate scientist at the CHEO Research Institute and co-leader of the city’s wastewater project, said the Omicron subvariants that drive high transmission rates and hospitalizations in parts of Europe and elsewhere are now taking off “by leaps and bounds.” in Ottawa and across the province.
Those Omicron subvariants include BA.4, BA.5 and BA2.12.1. Graber said it’s not yet clear which one will dominate in Ottawa, but BA.4 rose as recently as last week.
All three, but especially BA.4/BA.5, are significantly more infectious than previous Omicron subvariants, according to evidence from parts of the world where they already dominate. They also have a greater ability to evade immunity from vaccines and previous diseases. And there is some early evidence that BA.5 is more virulent than previous Omicron subvariants and more likely to infect the lungs.
Despite the subvariants’ ability to escape previous immunity, Graber said the rise could lead to more of a bump locally than the steep waves seen in some other countries because vaccination rates are so high. But some kind of increase is to be expected.
“I don’t think it will blind us. But we’re not done with that yet.”
In recent weeks, Ottawa Public Health has been warning that signs point to a new wave of COVID-19. OPH encourages people to get vaccinated, wear a mask and stay home if they are sick. OPH reported 225 new cases of COVID-19 on Tuesday, one additional death and two new outbreaks in the past four days.
Other parts of the world have been hit hard by BA.4 and BA.5.
In parts of the UK, hospital admissions doubled within a week earlier this month as the BA.4/BA.5 wave kicked off. It is unclear whether hospital admissions are increasing because the subvariants are so contagious, whether they make people sicker, or a combination of both.
Hospitals across Ontario are experiencing record volume amid critical staff shortages, causing some to close emergency rooms and others to postpone operations and procedures. Any increase in COVID-related hospitalizations this summer would contribute to the crisis.
But Ottawa’s relatively high vaccination coverage and number of people previously infected are expected to protect against serious illness even if people become infected, experts say.
University of Ottawa virologist Earl Brown said people should be aware that “we are not completely out of the woods” with COVID-19. But he said it’s unlikely the upcoming surge will be a reason to return to lockdowns.
Both Brown and Ottawa Public Health recommend that people assess their own risk and use public health strategies to protect themselves. These include meeting people outside instead of inside, masking and staying home when they are sick. Virtually all mask mandates — except in long-term care and retirement homes — were scrapped in Ontario earlier this spring.
There are mounting calls for the Ontario government to expand access to fourth doses of vaccines as people’s immunity to previous vaccinations wanes, something other provinces have done.
Currently in Ontario, only people over 60, indigenous peoples and their relatives, and vulnerable populations, including people living in long-term care and retirement homes and people with weakened immune systems, are eligible for a fourth dose, or second booster injection, of a COVID -19 vaccine.
The wave of early summer cases is breaking the pattern of previous summers since the pandemic began in 2020. Overall, transmission has remained relatively low and stable in previous pandemic summers, and cases started to increase in the fall as more people gathered indoors.
That pattern seems to be changing this year.
“For those who think this is a seasonal disease, this is proof that it isn’t,” Graber said.