Canada could give 75 per cent of adults their first COVID-19 vaccine dose by mid-June if provinces stretch the dosing intervals between COVID-19 jabs up to four months, the National Advisory Committee on Immunization said Wednesday.
The advisory committee doubled down on its four-month recommendation in a Wednesday morning report, which comes as the country struggles to roll out vaccinations quickly enough to stem the tide of a third COVID wave.
By allowing for these intervals, nine out of 10 adults over 50 years of age and 75 per cent of adults aged 16 to 49 will be able to get their first vaccine dose by the middle of June, according to a summary within NACI’s decision.
“Extending COVID-19 vaccine dose intervals will optimize vaccine rollout and protection of the population by allowing many more people to gain protection against COVID-19 by receiving the first dose of a COVID-19 vaccine earlier,” the summary of NACI’s decision read.
However, they’re still calling for second doses to be offered “as soon as possible” after all eligible populations have been offered first doses.
Officials are expected to tighten the timeline between doses as more vaccines arrive in Canada.
“What we are expecting to see, as the provinces and territories officially roll out the programs, is that that period of time actually can decrease as more and more people are getting vaccinated,” NACI’s Dr. Shelley Deeks said in a Wednesday press conference.
“A number of jurisdictions are already under discussion about decreasing the interval based on where they are in the delivery of the program.”
Later in the same press conference, NACI’s Dr. Caroline Quach said this interval could decrease to about two months.
“What we’re expecting in terms of supplies is that as supplies roll in and we have enough, that interval will decrease,” Quach said.
“Our estimate is that eventually we will be able to go close to two month-and-a-half, or two months interval between doses, but that really will depend on how many doses come in.”
The two-dose vaccine regimens were originally mandated to be administered no more than three to four weeks apart. However, in March, NACI stretched that interval to up to four months amid vaccine shortages.
Both the Pfizer and AstraZeneca vaccines are being given three months apart in the United Kingdom, though officials acknowledged on Wednesday that Canada “might be the only one” with a four-month interval.
“A number of countries are using extended intervals,” Deeks said.
By implementing this interval, Quach said, they’re able to try to “achieve the greatest level of vaccinations collectively.
“We have to weigh the benefits of vaccinating the greatest number of Canadians quickly rather than vaccinating, perhaps, fewer Canadians and getting them both doses,” Quach said in French.
There are numerous benefits to getting one shot administered to as many Canadians as possible – even if that means delaying the second dose, according to NACI’s report.
“Vaccination of larger numbers of people with vaccines that prevent infection and transmission will not only protect the vaccinated individual but those around them as well,” the report explained.
“In addition, extending the interval between doses in order to more rapidly vaccinate an increased number of people is likely to decrease the overall circulation of the virus in the community contributing to community protection.”
Both mRNA-based vaccines, Pfizer and Moderna, have a 92 per cent efficacy after just one shot, according to observational studies. Similar studies of the AstraZeneca jab show 76 per cent efficacy after just one shot.
“While two doses of mRNA vaccines have shown excellent efficacy and effectiveness, one dose of mRNA vaccines appear to perform similarly to one or two doses of the AstraZeneca vaccine… and the single-dose Janssen vaccine,” NACI explained in the report.
And as variants continue to surge across the country, NACI acknowledged that the impact these intervals might have on the emergence of variants is unknown – but there is “no evidence” the intervals will either “increase or decrease the emergence of variants of concern.”
“Although preventing transmission in the community by vaccination may decrease the chance of the emergence and/or spread of variants as suggested in a recent publication,” the report stated, citing a paper published in Nature Reviews Immunology.
Meanwhile, provinces are rushing to ramp up their vaccination rollouts and get those first jabs into Canadians’ arms. The vaccines are starting to arrive into the country in larger quantities, and thousands are sitting in freezers as provinces rush to ensure vaccines are going to those who need them most.
“I think people recognize the fact that we must all speed up the vaccination process,” Prime Minister Justin Trudeau acknowledged on Tuesday, offering to step in if the provinces need a hand.
Trudeau added that the government is still pushing to have the entire country fully vaccinated before the fall.
“As I’ve said, we intend to have every Canadian fully vaccinated – who wants one – by the end of the summer,” Trudeau said.