Canada's first shipment of Johnson & Johnson's single-dose COVID-19 vaccine is expected to arrive in the coming days, but provinces are still waiting for guidance on how best to use them.
Procurement Minister Anita Anand said last week that Canada would receive 300,000 doses by the end of this week, with distribution to provinces and territories beginning in early May.
While the initial shipment may not seem large enough to be a game-changer in Canada's rollout, experts say every little bit helps at this stage of the pandemic.
"It's not a lot, but it's not zero," says Dr. Andre Veillette, a professor of medicine at Montreal's McGill University and a member of Canada's COVID-19 vaccine task force.
"The impact may not be in the number, but in reaching specific groups of people that are harder to reach with the currently available vaccines."
The ease of distribution offered by a single-dose shot -- unlike the two-dose vaccines from Pfizer-BioNTech, Moderna and Oxford-AstraZeneca -- and its ability to be stored in a regular fridge are among Johnson & Johnson's biggest strengths, says Veillette.
But, he adds, it will be up to provinces to decide how they'll allocate their doses, including which groups they'll target with the one-and-done shots.
Ontario said Monday its deployment would reflect guidance from the National Advisory Committee on Immunization, which is yet to come.
NACI chair Dr. Caroline Quach said in an email to The Canadian Press on Monday that recommendations "should be available within 7-10 days."
The first Johnson & Johnson shipment lands in Canada days after the U.S.-based Food and Drug Administration and Centers for Disease Control and Prevention lifted their recommended pause on the vaccine south of the border.
The pause, which ended Friday, was put in place nearly two weeks ago after reports that an exceedingly rare type of blood clot was seen in six recipients -- out of 6.8 million doses given. The reviewing bodies found the risk of clotting to be very low and that the vaccine was safe and effective.
The clots appeared similar to the rare events seen in a small minority of recipients of the AstraZeneca vaccine, which led NACI to initially recommend limiting that shot to those aged 55-years and older. The agency has since updated its guidance to allow people age 30 and older to get the vaccine.
Dr. Sumon Chakrabarti, an infectious disease expert in Mississauga, Ont., says he expects NACI may attach an age-based cutoff to their guidance on Johnson & Johnson. But he stresses that the clotting issues were very rare.
"In Canada, we're still having a lot of community transmission of COVID," he says. "So for us, the benefit still greatly outweighs the risk."
Chakrabarti says Johnson & Johnson's product is conducive to large, mobile vaccine clinics that can be set up quickly to target populations in hard-hit communities or remote areas that may be harder to reach with other vaccines.
He says all of the approved vaccines can be used to alleviate pressure in hard-hit areas -- adding that pop-up clinics have already set up in some Ontario hot spots, for example -- but Johnson & Johnson brings another powerful tool.
"This has the benefit of only needing a single dose," Chakrabarti says. "And that's going to be huge. If you're going to essential workers in Brampton, a one-and-done is amazing."
Veillette says a single-dose inoculation can also help protect people like truck drivers or those experiencing homelessness, who may be harder to book for a second dose of another vaccine.
But while the risk of blood clots is rare, Veillette adds that any recipient would need to be informed of what signs to look for post-inoculation.
"It adds another level of complexity," he says. "We have to at least make sure they're amenable to reach a physician if they had symptoms."
Johnson & Johnson announced promising results from its Phase 3 clinical trials at the end of January, suggesting its vaccine reduced severe COVID-19 disease by 85 per cent, and prevented 100 per cent of COVID-related hospitalization or death.
Chakrabarti says all of the approved vaccines start working immediately to produce antibodies that can recognize future COVID-19 infections, but they likely need about a week or two to reach a good level of immunity.
"By about two weeks, you're starting to already see it take effect and by one month you have pretty good (protection)," he says. "And it probably keep increasing after that."
This report by The Canadian Press was first published April 27, 2021.
