OTTAWA -- The national vaccine panel providing advice on how to prioritize the use of COVID-19 vaccines says that the Johnson & Johnson vaccine should be offered to Canadians aged 30 and older, similar to its latest guidance around the AstraZeneca vaccine.

The National Advisory Committee on Immunization (NACI) is also suggesting that as a single-shot vaccine, it may be better to prioritize its use in populations that are harder to schedule for a second dose. 

However, the vaccine is currently not cleared to be distributed in Canada.

Health Canada announced late Friday that it was holding the first 300,000 doses of the Johnson & Johnson vaccine that landed in Canada last week for further quality assurance checks after learning that an ingredient in the vaccine was produced at a problem-plagued vaccine manufacturing facility in the U.S. 

Health Canada said what while the final Johnson & Johnson vaccines sent were developed by Janssen Pharmaceuticals at a different site located outside of the U.S., it needed to review the doses to ensure they meet quality standards before they are administered, something provinces were gearing up to do this week.

Deputy Chief Public Health Officer Dr. Howard Njoo—who is not a spokesperson for Health Canada—was the first federal official to speak publicly about the doses being held up. On Monday he told reporters that the agency continues to work with the U.S. Food and Drug Administration on its investigation.

“The vaccine is sort of in a holding pattern. It's certainly being held in freezers in good condition and until obviously Health Canada does its due diligence. I can't give a timeline… I think we can all appreciate they want to do a good thorough job, as quickly as possible,” Njoo said.

Should the doses be cleared for use, NACI said Monday that adults aged 30 and older should be prioritized to receive them so long as they do not have any contraindications.

“Similar to the AstraZeneca vaccine, NACI weighed the benefits of the Janssen vaccine in saving lives, and protecting populations against serious complications of COVID-19, against the risk of developing VIITT [vaccine-induced immune thrombotic thrombocytopenia],” NACI vice-chair Dr. Shelley Deeks said.

NACI issues guidance on the use of vaccines, but provinces and territories do not have to follow its recommendations.

On Monday, Deeks repeated the same caveat with Johnson & Johnson that she first offered in the latest advice around AstraZeneca: that if people did not want to wait for an mRNA vaccine they may opt to receive a viral vector shot if it is being offered to them.

Suggesting anyone opt to wait for a different vaccine than the first one offered is a message that doctors on the front line of the COVID-19 crisis have been highly critical of. It may not bare out in reality when looking at Canada’s scheduled vaccine shipments, with a far more reliable supply of mRNA’s coming into Canada than there are at present when it comes to AstraZeneca or Johnson & Johnson doses. 

NACI also restated Monday its preferential recommendation towards the mRNA Pfizer and Moderna doses over the viral vector AstraZeneca and Johnson & Johnson shots.

"The viral vector vaccines are very effective vaccines, but there is a safety signal, a safety risk… And the issue with the safety signal is that although it is very rare, it is very serious. And so individuals need to have an informed choice to be vaccinated with the first vaccine that's available, or to wait for an mRNA vaccine,” Deeks said, referencing the rare clotting concerns.

Raising questions about this advice, Conservative MP and health critic Michelle Rempel Garner asked Health Minister Patty Hajdu during question period what Canadians should make of it. In response, Hajdu suggested people speak with a medical professional.

During the press conference, NACI officials were asked what they would say to the approximately two million Canadians who have received a viral vector AstraZeneca vaccine and may be wondering about whether they should still get a second dose once the supply arrives or whether they should be looking to receive a shot of an mRNA vaccine. Deeks said that the vaccine they have been given is safe and effective but the committee is currently examining the idea of mixing and matching shots.

“We as a committee are looking at options... As of now, though, there is no reason for people to not receive a second dose of an AstraZeneca vaccine or an mRNA vaccine… NACI will be making a recommendation about mixed schedules as soon as we see some information from some studies,” she said.

NACI also restated Monday that people previously infected with the SARS-CoV-2 virus should be offered a complete series of a COVID-19 vaccine.

“In the absence of one-dose vaccine effectiveness data in people who were previously infected and limited second-dose safety data, people with previous SARS-CoV-2 infection should continue to receive a complete vaccine series, regardless of the severity of their previous infection,” said NACI in its latest release

Health Canada first authorized the use of the Johnson & Johnson vaccine in adults 18 years of age and older, on March 5. 

It’s been suggested that the addition of Johnson & Johnson vaccine into Canada’s COVID-19 vaccine toolkit could help expand the kinds of sites where shots can be given, as vials stay stable if unopened for up to 12 hours and can be kept for three hours at room temperature once the seal has been punctured.

In clinical trials involving approximately 43,000 participants, this vaccine was shown to be 66 per cent effective in preventing moderate to severe COVID-19, two weeks after vaccination.

As with other vaccines, common side effects such as muscle pain, fever, and chills, and have been reported after receiving this vaccine. However, after concerns were raised about blood clots, similar to those seen with the AstraZeneca vaccine, Health Canada updated its label to include the “very rare” side effect. The agency said at the time that the benefits of the vaccine still outweighed the risks. 

In total, Canada has a deal with Johnson & Johnson for 10 million doses. The federal government has said all 10 million shots should arrive by the end of September, but beyond the first shipment the government has not said when the next batch is set to land.