In announcing the approval of the Johnson & Johnson vaccine produced in conjunction with Belgium’s Janssen on Friday, Health Canada’s chief medical adviser said a review of data from a clinical trial involving more than 44,000 participants found the shot is safe and effective.

„As with all COVID-19 vaccines, Health Canada authorized the Janssen one after an independent and thorough scientific review for safety, efficacy and quality,” said Dr. Supriya Sharma.

While the vaccine tested less effectively in its trial for moderate illness than previously approved vaccines from Pfizer-BioNTech and Moderna — both of which had efficacy rates of 90 per cent and above — the three trials were not identical. The Johnson & Johnson trial took place at a time and in countries where more transmissible coronavirus variants had developed, while the South African trial also included some patients who are HIV-positive.

Dr. Bob Wachter, chair of the department of medicine at the University of California, San Francisco, likened comparing the trials to comparing golf scores between duffers who teed off in calmer conditions to those who did so when „winds were howling.”

Sharma noted that the J&J single-shot offers strong protection against the threats that matter most: serious illness, hospitalizations and death.

The single-shot aspect brings optimistic possibilities in both urban and remote settings, experts told CBC’s Lauren Pelley.

„You can way more easily get a vaccine like this into primary care clinics and pharmacies, which means that you can distribute it so much more broadly,” said Dr. Isaac Bogoch, who is a member of Ontario’s vaccine task force.

The applications for developing nations were noted by Dr. Zain Chagla, a Hamilton, Ont.-based infectious disease specialist and professor at McMaster University.

„This is a vaccine that could go into mass vaccine clinics in low- and middle-income countries that could be stored on the back of a motorcycle to make it into a very, very remote setting,” said Chagla. „That is very, very different than anything we have in that sense.”

The nub for Canada is the supply issue. There is no timeline yet for delivery this year, though Prime Minister Justin Trudeau said Friday that the president of Janssen Canada, Jorge Bartolome, assured him this morning that the company is working to set up its global supply chains and plans to meet its delivery commitments.

But Johnson and Johnson had to strike a deal recently in the U.S. with pharmaceutical company Merck to ramp up production for tens of millions of doses for the American market. The doses there are scheduled to be distributed in a matter of months, which leaves open to question how much excess capacity will be available for other nations, and when.

Nevertheless, with a fourth vaccine now approved for the Canadian population eligible for vaccination, federal officials expressed optimism Friday that supply overall will soon cease to be an issue.