Quebecers who got AstraZeneca shot left in limbo as other provinces put vaccine on hold

Roughly half a million Quebecers who received a dose of AstraZeneca are left without clarity about what they willreceive for their second dose, after the province's Health Ministry said it is awaiting advice fromits immunization committee about what to do for their second doses.

In a statement Tuesday, the Health Ministry said it has hardly any doses of AstraZeneca left and the few that remain are only available to those 45 and up.

Appointments for the AstraZeneca vaccine are clearly marked on the province's booking website.

Ontario, Saskatchewan and Alberta have all paused the use of the vaccine for first doses.

Dr. David Williams, Ontario's chief medical officer, announced late Tuesday the vaccine would no longer be offered to Ontarians as a first dose and future supply would instead be reserved for optional second shots.

Williams said that in the past several days there have been a growing number of cases of rare blood clots in Ontario known as vaccine-induced immune thrombotic thrombocytopenia (VITT).

Saskatchewan's chief medical health officer, meanwhile, said it's "likely" those who received AstraZeneca as their first dose of COVID-19 vaccine could have Pfizer-BioNTech for their second due to supply issues.

Quebec has received 524,340 doses of AstraZeneca, according to the federal government. The federal government said Wednesday it would receive more than 600,000 doses next week.

Mixing vaccines can increase reaction risk, study finds

New international research is expected in the coming days and weeks on the safety and efficacy of mixing and matching COVID-19 vaccines and Canadians who have received an initial dose of AstraZeneca will likely have the option of combining it with an mRNA shot.

The early results of one U.K. study were published Wednesday. It has foundthat mixing different types of COVID-19 vaccines for two doses can hike the chance of someone having mild or moderate reactions like fatigue, headache or a fever.

"Both of the mixed schedules caused more symptoms than the standard schedules," said study leader Dr. Matthew Snape, an associate professor in general pediatrics and vaccinology at the University of Oxford, during a media briefing on Wednesday.

Most of these effects are mild,he said, though the findings did also show an increase in moderate reactions.

Data from the United Kingdom also points to a much-reduced risk of VITT in second doses of AstraZeneca. The risk of VITT in second doses of AstraZeneca is about one in a million, according to data cited by Williams.

WATCH | Dr. Theresa Tam on mixing vaccines:

Tam talks about AstraZeneca second doses and mixing vaccines

3 years ago

Duration 1:34

Dr. Theresa Tam, Canada's chief public health officer, says the government will ensure that people can get their second doses of AstraZeneca's COVID-19 vaccine and Health Canada will continue to review studies on mixing vaccines.

Dr. Horacio Arruda, Quebec's director of public health, said earlier Tuesday the vaccination committee is awaiting the results of those studies before deciding next steps.

He also pointed out that the recommended delay between doses of AstraZeneca is 12 weeks, so the province has time before making a determination.

"As I have always said, we will ensure that we will not give them a vaccine that they do not want or are not informed about, then we will make sure to offer the best combination to protect Quebecers, while being safe," Arruda told reporters.

Canada has reported 12 confirmed cases of VITT as of Monday out of more than 2.3 million AstraZeneca doses administered, according to the Public Health Agency of Canada. Quebec, Alberta and New Brunswick have each reported one death; New Brunswick has only 40 COVID-19 deaths overall.