Canada's chief science advisor doesn't back vaccine dose delay.
Canada has dropped the ball by delaying second doses by 105 days to cover up its supply shortfalls.
The Liberal government’s failure to procure enough COVID-19 vaccines is hurting the economy, which is why many provinces have opted to delay the second dose in order to get as many people partially vaccinated as possible in short order. But a new study out of the United Kingdom suggests this strategy could be putting lives at risk.
Pfizer and Moderna recommend that their two doses be given around 21 days apart, but Health Canada and the National Advisory Council on Immunization have agreed to stretch it out to 105 days, solely because of Ottawa’s procurement bungling.
A new study out of the U.K., which was conducted by a team at King’s College London and the Francis Crick Institute, found that delays in administering the second dose of more than 21 days leaves cancer patients vulnerable to COVID-19.
The study, which has not yet been peer-reviewed, found that people who have cancer are less “protected” if they have to wait for their second shot. Lead scientist Dr. Sheeba Irshad also said that leaving people unprotected for many weeks could give new variants the chance to emerge and allow the virus to spread among family members caring for patients.
In Canada, there are roughly 225,800 new cancer cases each year and two million Canadians have had, or currently suffer from, the disease. Cancer incidence climbs with age.
The study showed that three weeks after one dose of the Pfizer vaccine, an antibody response was found in only 39 per cent of those with cancer, compared to 97 per cent for those without. If a second dose occurred three weeks after the first, the cancer patients’ antibody responses sharply rose and matched those of the others. If delayed, the response stayed around 39 per cent.
“One size does not fit all,” Irshad told the BBC. “Cancer treatments have profound effects on the immune system and cancer patients’ immune mechanisms are inferior. We need to be concerned about other vaccines (in addition to Pfizer’s) for this population, too. They do need a second dose quickly.”
Irshad recommended that Britain’s 12-week gap (Canada’s now stands at 15 weeks) should be reviewed immediately. The charity Breast Cancer Now has called on the U.K.’s vaccine committee to “urgently review the evidence presented in this study and consider adapting its strategy” to give people with cancer both doses within three weeks.
Cancer Research UK said the small study was interesting, but a spokesman noted that, “Anyone undergoing cancer treatment should continue to follow the advice of their doctors and we encourage all who can to take up the vaccine.”
It certainly appears as though spacing the second jab out by three weeks should remain sacrosanct, at least for cancer patients.
Another issue concerns whether or not AstraZeneca’s vaccine is as effective as the Pfizer or Moderna jab when it comes to dealing with the variants that are currently circulating. This compounds Ottawa’s procurement fiasco.
Canada has dropped the ball by delaying second doses by 105 days to cover up its supply shortfalls. We are now beginning to see that lives may be at risk due to this reckless decision.
https://financialpost.com/diane-fra...oses-of-covid-vaccine-could-put-lives-at-risk
TORONTO -- Canada’s top scientist is advising against extending the time between doses of the COVID-19 vaccines to four months in seniors, arguing the research isn’t there to justify the delay for that population and those with pre-existing conditions.
In early March, Canada’s National Advisory Committee on Immunization (NACI) issued an updated guidance indicating that the interval between doses of the Pfizer-BioNTech, Moderna, and AstraZeneca vaccines could be extended to four months while still being effective.
The changed guideline led several provinces, including Ontario, Manitoba and British Columbia, to alter the vaccine rollouts to include more age groups, but it means that second-dose appointments are being pushed back further than manufacturer recommendations.
Canada’s chief science adviser Dr. Mona Nemer told CTV News Channel’s Power Play on Monday that studies have shown that extending the interval between doses has had a negative effect on their efficacy, particularly in seniors.
“I’m not aware of data showing that there is efficacy beyond two months of the first dose,” she said. “In the past few weeks, we’ve seen different studies come out showing that the response to the first dose of the vaccine in the people who are elderly, in the people who are immuno-compromised is actually not that good and it wanes quite rapidly.”
Last week, preliminary research out of the U.K. indicated that 95 per cent of cancer patients produced an antibody response if they received the second dose of the Pfizer vaccine three weeks after their first, while only 43 per cent of patients showed the same responses if they waited five weeks between doses.
Health Canada’s authorization for the vaccines initially indicated a 21-day interval between doses of the Pfizer-BioNTech vaccine, 28 days between doses of the Moderna version, and up to 12 weeks between doses of AstraZeneca.
The NACI said it came to the decision to extend the intervals after considering evidence from scientific research and “real world effectiveness” that shows high levels of protection following a single dose.
Given the vaccine supply issues at the time, the NACI recommended that it would be more beneficial to maximize the number of people receiving a single dose, rather than hold on to doses for a second appointment.
Nemer said both Health Canada and the NACI will also have access to the updated findings, meaning a new recommendation could be on the way.
“I’m sure they’re following this and they may well be looking at perhaps modulating the recommendation as we go,” she said.
“As data emerges about what it takes to protect [seniors and immune-compromised people], we need to be reviewing what we’re doing.”
Nemer said as long as there aren’t issues with the vaccine supply, reverting to the original recommendations from the pharmaceutical companies “would be the ideal approach.”
“The very people we want to protect the most require that we give them the second dose using the shorter interval, originally as done by the manufacturer in the clinical trials,” she said.
“The one-size-fits-all approach really needs to be modulated in terms of who we need to be protecting.”
Canada is expecting more than two million doses of the Pfizer and Moderna vaccines to arrive this week, while another 1.5 million doses of the AstraZeneca vaccine are expected to arrive by the end of the month.
https://www.ctvnews.ca/health/coron...canada-s-chief-science-adviser-says-1.5358075
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