Astrazeneca recipients torn about second dose options
As new research continues to roll out, many wonder whether mixing and matching would be more effective
As new federally funded research gets underway into the viability of mixing and matching COVID-19 shots, surveys suggest feelings are also mixed among Newfoundlanders and Labradorians who received an initial shot of the controversial Astrazeneca vaccine.
A national Angus Reid poll released this week found that almost half of Canadians who received the shot are completely satisfied with their choice, even though many provinces have stopped administering it as a first shot. A similar number admit the MRNA vaccines — Pfizer and Moderna — would have been better, but have no strong feelings or regrets.
While few people express serious regrets on social media about getting the Astrazeneca shot, an informal Twitter poll conducted Wednesday by The Telegram found the same is not true about what booster shot they should get.
About 54 per cent said they’d prefer to get Pfizer as a second dose, while 43 per cent want the same vaccine they received. The rest chose Moderna.
“I received AZ as my first dose based on advice that it was safe,” wrote one responder. “I am not an expert so rely on (the chief medical officer of health) to tell me what’s safe. Not sure which one I will get as a second dose.”
Reliance on expert advice seemed to be the predominant theme, but most who commented said they plan to dance with the one that brought them.
“To complete this first round, as I’m sure it won’t be the last in the years ahead, I think I’d just as soon go with the AZ,” wrote one.
“I am not interested in mixing mine,” wrote one. “I don’t even like mixing my drinks throughout the night.”
The poll received more than 150 clicks.
MIXED MESSAGES
The divergent views are understandable, given that Astrazeneca went from respectable first choice to vaccinus non grata in a matter of months.
First, what was thought to be an unrelated blood clot condition turned out to be a rare but recognized risk with a probability as high as one in 100,000.
Then the National Advisory Committee on Immunization (NACI) changed gears in early May and suggested most people should wait for the more effective MRNA vaccines if they could.
Last week, Newfoundland and Labrador joined several other provinces in no longer offering it for a first shot, but Chief Medical Officer of Health Dr. Janice Fitzgerald said Wednesday it will still be available as a second dose. She also promised to move the interval up to 12 weeks from 16, as 12 weeks has been found to be the most effective time between shots.
That means those who want it can expect more information soon on how to rebook for an earlier booster.
CLINICAL STUDIES
Meanwhile, Canada is joining other nations in funding research on the safety and efficacy of mixing and matching.
A $4.8-million study announced Thursday will also study the effects of increasing the interval between doses.
Researchers are hoping to enrol 1,300 participants as soon as possible across clinical trial sites in Nova Scotia, Quebec, Ontario, Manitoba, Alberta and British Columbia.
Dr. Joanne Langley, co-principal investigator and a professor at Dalhousie University, said she hopes volunteers will get shots at the Halifax testing site within the next week, but first data on the immune response for different combinations will take time.
“The first immune responses would probably not happen until early July, or some time in July,” Langley told The Telegram Thursday.
Some participants will get
second doses at one month and others at four months. Every combination of Canada’s three approved vaccines will be examined, except that the only subjects with a first dose of Astrazeneca will be those who already received one before the study.
An ongoing study in the U.K. expects to release evidence on immune response in mixed doses by June, but a preliminary report last week found recipients experienced slightly more intense minor side-effects such as fever and headache on the second dose.
Langley said such side-effects are not a big concern.
“We expect some side-effects from vaccines because those … are a sign that your immune system is responding to the vaccine.”
More importantly, she said, the U.K. study only looked at the senior population. Langley said the Canadian trials hope to enrol more people under the age of 50.
“It’ll be important to know whether the same profile of side-effects occurs in young people,” she said. “Hopefully, we’ll be able to tell that.”