Infectious disease expert calls NACI’s suggestion of preferred vaccine type ‘problematic’

The best COVID-19 vaccine is the first one you're offered, according to an eastern Ontario infectious disease expert, after a federal panel called mRNA vaccines against COVID-19 “preferred” because of the very rare risk of blood clots from other vaccines.

The National Advisory Committee on Immunization (NACI) said this week that Canadians who aren't at high risk of COVID-19 may choose to wait until they can get the Pfizer-BioNTech or Moderna shots, which don't carry the risk of the rare blood-clotting syndrome.

The panel's comment contradicts months of federal government messaging that said all vaccines are safe, and that people should take the first one they're offered.

A Queen's University medical expert said NACI's use of the term “preferred,” in reference to a potentially life-saving vaccine, is problematic.

“Because it does suggest to people that it's a preference,” said Dr. Gerald Evans, chair of the division of of infectious diseases, Queen's University. “Like, you're at a grocery store and you're looking between two different kinds of cookies, and one is preferred over the other one.”

“I think that's not the right way to put it.”

Evans said the vast majority of the population is not at risk of the rare blood clotting syndrome, and that the best vaccine for people to get remains the first one they're offered.

“I think everybody has to put it in perspective: the rarity of the thrombosis problem that has been seen with the anti-virus vector vaccines, and the real, true threat of serious illness, hospitalization and death, from COVID-19,” said Evans.

“If you get offered AstraZeneca or Johnson & Johnson, take it.”

The risk of the new blood-clotting syndrome is estimated to be anywhere from one case in 100,000 doses given, to one in 250,000.

– With files from The Canadian Press