OTTAWA | Scientists are calling for delaying the administration of a second dose of the vaccine in order to quickly deliver at least one injection to as many people as possible.
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The manufacturers of the two vaccines currently licensed in Canada, Moderna and Pfizer, recommend two doses three to four weeks apart for optimal efficacy.
For this reason, many jurisdictions store vaccines in the freezer between the two injections. The goal is to ensure that possible delivery times do not prevent having the second dose on hand on time.
But Dr Gary Kobinger, who co-developed the Ebola vaccine, tells the Newspaper having recommended that the Quebec government administer a first dose to as many people as possible, even if it means delaying the second injection.
“What we’ve seen in studies of immunization in general is that the longer you wait [pour la seconde dose], the better. And after six months, it’s optimal, “says the researcher at the Department of Microbiology-Infectious Disease and Immunology at Laval University.
For Dr. Kobinger, we must speed up the pandemic by breaking the chain of contamination quickly, otherwise we risk having to live with the virus for several more years.
30% of cases avoided
Ashleigh Tuite of the Dalla Lana School of Public Health at the University of Toronto, and her colleague Joshua Salomon of Stanford University in California, agree.
In an analysis published Tuesday in the scientific journal Annals of Internal Medicine, they calculate that, over an eight-week period, 27-32% of new cases of COVID could be prevented by giving just one injection.
When asked about this, Dr. Theresa Tam, Chief Public Health Officer of Canada, did not discourage this strategy. Conversely, his American counterpart, Dr. Anthony Fauci, recommends following the manufacturers’ rules to the letter.
Mr. Fauci opposes the advice of Dr. Moncef Slaoui, the scientific adviser to Operation Warp Speed, who is even considering the option of diluting the doses.
For Gary Kobinger, this option should not be ruled out. He points out that doses of Ebola and yellow fever vaccine have been successfully diluted.
“In a state of emergency, companies do not want to miss their mark. So they give more to make sure it works, he explains. But I am sure that over time, we will give less without significantly reducing the effectiveness. “