'Dominant strain in Ontario': Province expands COVID-19 fourth dose eligibility to all adults as BA.5 soars

The Ontario government announced Wednesday that all adults in the province will be eligible to book an appointment for a fourth dose of a COVID-19 vaccine, a second booster shot, on Thursday, July 14.

Dr. Kieran Moore, Ontario's chief medical officer of health, indicated that the expansion in eligibility for fourth doses of a COVID-19 vaccine is coming as the province is in the seventh wave of the pandemic, led by the BA.5 Omicron subvariant.

"This variant has been increasing in prevalence since early June and is now the dominant strain in Ontario," Dr. Moore said at a press conference on Wednesday. "BA.5 is more transmissible, which is reflected in the data we have seen in the last few weeks, including an increase in the provincial wastewater signal, as well as increases in per cent positivity, COVID-related hospitalization and ICU admissions."

While the eligibility is expanding, Dr. Moore stressed that for younger, healthy Ontarians, with no underlying health conditions, a fourth dose of a COVID-19 is not "absolutely necessary" at this time, and those individuals can wait until the fall to receive their next dose of a COVID-19 vaccine.

"We’re now opening up eligibility to those between 18 and 59 years of age that have evidence to support them getting a second booster dose," Dr. Moore said. "Primarily, those who should consider getting that vaccine are those with underlying medical illness, because they’ll get the greatest benefit."

"So if you haven’t had your booster dose yet, you’re between 18 and 59, and you smoke or have diabetes and/or any underlying illness, please consider getting that booster dose."

Ontario's chief medical officer of health added that for anyone who gets a second booster dose now, it "should not" block their eligibility for another shot later this year, expected to be a bivalent COVID-19 vaccine that will offer more targeted protection against the Omicron COVID-19 variants.

“If Ontarians get a dose, this second booster dose, we will have a minimum separation between the fall dosing and this dose, but it will not interfere with your eligibility for the fall, which is a combined vaccine, which may have two different strains of COVID-19 in it," Dr. Moore said.

He added that the interval between any COVID-19 vaccine doses administered in the summer and a bivalent vaccine expected to be offered in the fall is anticiapated to be around five months.

How can you get an appointment for a fourth COVID-19 vaccine dose?

Second booster shots are being offered at an interval of five months after an individual receives their first booster dose, or at least three months after a COVID-19 infection.

Ontarians can book an appointment through the COVID-19 vaccination portal or by calling the Provincial Vaccine Contact Centre at 1-833-943-3900. Appointments can also be booked directly through public health units that use their own booking systems, through Indigenous-led vaccination clinics and participating pharmacies. The provincial government has indicated that appointments are based on availability, which may vary by region.

COVID-19 rapid tests

The Ontario government also confirmed that free COVID-19 rapid antigen tests will continue to be made available across the province, through existing channels like grocery stores and pharmacies, as well as workplaces, schools, hospitals, long-term care and retirement homes, and other congregate settings, until Dec. 31.

Dr. Moore provided additional guidance on the effectiveness of these tests, indicating that their sensitivity to be able to detect COVID-19 has "gone down," but stands at around 50 to 60 per cent.

"If [the test] is positive, we consider it a true positive," Dr. Moore said. "If it’s negative, one negative test does not rule out COVID-19."

"You’d want to do another 24 hours apart, make sure you’re having good technique,...and follow the instructions properly. Two negatives is less likely that you have COVID-19, but if you’re at risk or having severe symptoms, you may still be eligible for a PCR test in that instance."

Masking in the contingency plan for the fall, not now

As Ontario manages that seventh wave of the pandemic, the province's chief medical officer of health was asked about the possibility of reinstating some protective measures, like masking. Dr. Moore indicated that masking, in particular, is part of a "contingency plan" for the fall, if the health system is threatened to the point where there is a significant impact to ICU and hospitalized care.

"We’re certainly not at that point," Dr. Moore said. "Roughly 70 per cent of our ICU beds are being utilized,…that will go up over the next two weeks but it shouldn’t impede or impact any local hospital’s ability to care for individuals."

"So if that is threatened, we would make recommendations to government on universal masking in multiple settings."