Which COVID-19 vaccine should you get? Canada’s expert panel says, ‘That depends ...’
|Toronto Star 03 May 2021 at 21:09|
OTTAWA—You would be forgiven for thinking this whole vaccine rollout business is confusing, Canada, because it is. Chaotic, confusing and contradictory.
Questions about COVID-19 vaccinations — Where to get a first shot? How long to wait for a second shot? Does your second dose need to be the same vaccine as your first? Which restrictions will ease once you are vaccinated? — are all taking on new urgency as the national rollout picks up speed this week.
Adding to the confusion, the National Advisory Committee on Immunization (NACI) said Monday that Johnson & Johnson’s single-dose Janssen vaccine, like AstraZeneca’s double-dose vaccine, is safe for use by people over 30 if they can’t wait for one of the two “preferred” vaccines, the mRNA made shots by Pfizer and Moderna.
All four vaccines are approved by Health Canada as safe and effective for people aged 18 and over, based on clinical trial evidence.
But as millions of vaccines were jabbed into arms, the “real-world” picture shifted slightly for the viral vector vaccines made by AstraZeneca and Johnson & Johnson.
Reports of very rare blood clots showed up in Europe for AstraZeneca, then in the U.S. with Janssen, first at a rate of one in a million, now at an estimated rate of about 1 in 100,000 cases, said NACI vice-chair Dr. Shelley Deeks.
“What we’re saying — and what we’ve been saying all along — is that mRNA vaccines are the preferred vaccines.”
After reviewing the latest data, NACI recommends that provinces continue to administer the Janssen and AstraZeneca vaccines if the benefits outweigh the risks: it says both will reduce the chances of severe illness, hospitalization and death. And in a country where COVID-19 is still rampant, vaccines were slow to arrive and variants have taken hold, the benefits outweigh the risks of developing a rare but serious blood clotting condition called vaccine-induced immune thrombotic thrombocytopenia or VITT, the NACI concluded.
It cautioned that in age groups younger than 30, “the benefit of offering a viral vector COVID-19 vaccine instead of waiting for an mRNA vaccine is not a certainty, especially in areas of very low COVID-19 activity.
“On the other hand, the advantages of highly efficacious mRNA COVID-19 vaccines, with no safety signals of concern to date, clearly outweigh any possible disadvantages for most populations, and NACI made a strong recommendation for the preferential use of mRNA COVID-19 vaccines in all authorized age groups.”
NACI says it is now up to provinces to decide who should get priority access to which vaccines, said Deeks and NACI chair Dr. Caroline Quach-Thanh.
But individuals should also make an “informed choice” or individual risk assessment too, based on the prevalence of the virus in their communities and their exposure to it, along with an assessment of “their risk tolerance for an adverse event” – meaning a blood clot, said Deeks.
Individuals can decide “whether they’d prefer to get vaccinated sooner or wait to receive an mRNA vaccine,” she said.
“For instance if someone is working from home, not really going out in a province or territory where there’s not much disease, then they’re in a very different situation than somebody that works in, let’s say, a manufacturing plant, has difficulty wearing PPE and so in a province that has a very high burden of disease. So the risk benefit is very provincially dependent as well as group dependent.”
It is a definite change of tack from the public health message Canadians have heard since last December: from, “Get the first vaccine you’re offered,” to, “It would be nice to wait for an mRNA vaccine if you can — and if you can’t, the other ones are fine too.”
“There is so much confusion. It is a nightmare,” said global health epidemiologist Raywat Deonandan at the University of Ottawa.
By delivering advice without a clear and coherent message about how provinces will follow up, NACI is contributing to a “messaging fiasco,” Deonandan said.
The members of the vaccine advisory committee “seems to feel that it’s not their job to manage public expectations or behaviour or response,” he said. “And I understand that, but we’re in a new dynamic now where it is kind of everyone’s job to keep that in mind.”
NACI said it views the two mRNA vaccines as “preferred” because they have shown no “safety signal.”
But the risk with the mRNA vaccines “is not zero,” Deonandan pointed out. “It’s just that there are sufficiently large signals in the other two to warrant this concern.”
Many doctors and epidemiologists say the confusion around whether Canadians should take the first vaccine on offer or wait for a “preferred” one may contribute to even more vaccine hesitancy, especially among certain vulnerable populations who should be a priority to get vaccinated quickly.
“I’m really surprised they’d go this route, to be honest, to say the mRNA is better,” said Deonandan. “The thing about Johnson & Johnson that makes it so important is that it’s a one-shot vaccine, it’s easily stored and easily transported. And for populations like the homeless, or nomadic people, or migrant workers, this is our best shot because scheduling a followup dose will be very difficult for that population.
“And now the hesitancy in that population is going to be ratcheted up if they’re going to be told they’re getting the second-class vaccine,” he said. “So this is also an equity issue.”
For now, it may not matter — there will soon be several million more mRNA vaccine doses in the mix. Starting this week, Pfizer-BioNTech is ramping up its weekly Canadian deliveries to two million doses, and increasing them to 2.4 million doses a week in June.
Moderna is promising to resume bigger shipments to try to reach its planned target of 12.3 million doses for the second quarter, after it hit delays last month, with more than one million expected next week.
Meanwhile, questions remain about vaccine shipments from AstraZeneca and Johnson & Johnson.
On Friday, the federal government put a hold on Canada’s first shipment of 300,000 Janssen vaccine doses due to concerns the batch might contain an ingredient that came from a U.S. facility where authorities have red-flagged production problems.