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Canada’s public well being company says individuals can combine COVID-19 vaccines in the event that they need to, citing instances the place native provide shortages or well being issues would possibly in any other case stop some from finishing their two-dose vaccination routine.
The new suggestions come after security issues had been raised linking the AstraZeneca vaccine to the potential for harmful blood clots — a situation the health agency calls “rare but serious.” That vaccine just isn’t licensed to be used within the U.S., however the Johnson & Johnson vaccine, which has confronted comparable scrutiny, is. Both of them are viral vector vaccines.
Several Canadian provinces have just lately moved to combine vaccines, the CBC reported, due to provide points, when the vaccine used for a primary dose is not accessible for the second.
Public confidence can also be a difficulty: Health officers cite a study from late April that discovered greater than 90% of members mentioned they had been comfy with both the Pfizer or Moderna vaccines, however solely 52% of members mentioned they had been comfy with the AstraZeneca vaccine. Both Pfizer and Moderna are mRNA vaccines.
Based on the accessible proof, “we are recommending that someone who received a first dose of the AstraZeneca … vaccine may receive an mRNA vaccine for their second dose,” mentioned Dr. Caroline Quach-Thanh, who chairs Canada’s National Advisory Committee on Immunization.
The company cites the outcomes of a examine in Germany and medical trials within the U.Ok. and Spain as supporting the security of vaccine interchangeability. It says it expects additional information from ongoing research in Canada and elsewhere within the coming months and can replace its suggestions if warranted.
Two vaccines are dominant in each the U.S. and Canada
Nationwide, the Pfizer-BioNTech and Moderna vaccines have more and more turn out to be the first vaccines administered in Canada, in line with the latest government data.
The Pfizer-BioNTech and Moderna vaccines “can be considered interchangeable” between the primary and second doses, Canada’s advisory committee on immunization says in its suggestions that had been up to date this week.
Canadian officers are hoping the brand new steerage will assist bridge a large hole of their vaccination program. As of late May, 50.6% of Canada’s inhabitants had obtained at the very least one vaccination shot — however solely 4.6% of the inhabitants was totally vaccinated.
“This is not a new concept,” the advisory group mentioned of the apply generally known as heterologous vaccination. In the previous, the group added, “Different vaccine products have been used to complete a vaccine series for influenza, hepatitis A, and others to complete a vaccine series for influenza, hepatitis A, and others.”
Several European nations have already been encouraging individuals who’ve obtained a primary shot of the AstraZeneca vaccine to make both the Pfizer or Moderna vaccines their second shot, together with France, Spain and Germany.
Two vaccines could also be higher than one
In addition to probably easing vaccine reluctance, mixing vaccines may additionally deliver different advantages.
As NPR’s Joe Palca reported final month: “Basically, all vaccines work by showing people’s immune systems something that looks like an invading virus but really isn’t. If the real virus ever comes along, their immune systems will recognize it and be prepared to fight it off.
“Using two totally different vaccines is a bit like giving the immune system two photos of the virus, possibly one face-on and one in profile.”
As other countries authorize mixing vaccines, the U.S. is not following suit — in part because the Food and Drug Administration hasn’t authorized the AstraZeneca vaccine. And unlike that vaccine, the Johnson & Johnson vaccine requires only a single dose.
When asked for comment about the strategy of mixing vaccines, an FDA spokesperson cited a lack of data about the interchangeability of the vaccine with other COVID-19 vaccines.
“Individuals who’ve obtained one dose of the Pfizer-BioNTech or Moderna COVID-19 vaccine ought to obtain a second dose of the identical vaccine to finish the vaccination collection,” the spokesperson added.