MONTREAL -- Back in the spring, many Quebecers were faced with a difficult decision: should they get their AstraZeneca shot, or wait for alternative vaccines like Pfizer and Moderna?

Dan McWilliams and his wife chose to do the former, and received their AstraZeneca shots in April.

“I thought any vaccine — as the government was saying at the time — is better than no vaccine,” said McWilliams.

For their second shot, the couple decided to opt for an mRNA vaccine like Pfizer or Moderna, which many infectious disease specialists say offers a better immune response — even if it comes with the potential for more side effects.

“[An mRNA vaccine] allows your immune system to recognize something from different angles [...] so that you increase your repertoire of antibodies to that protein,” says Dr. Donald Vihn, expert in infectious diseases and immunity at McGill University.

Eight weeks later, McWilliams went to a walk-in clinic and was able to get the Pfizer vaccine. But when his wife went to do the same, McWilliams says she was turned away.

“They said, ‘We are afraid we are going to run out of Pfizer so, therefore, you have to wait for your original appointment day, which is the first of August, six weeks away,’” said McWilliams.

Currently, the official Quebec government website says that those who received AstraZeneca as their first dose and want to switch to a different vaccine for their second “must wait until their initial appointment and request a change of vaccine at the vaccination site.”

Meanwhile, the province announced that Moderna and Pfizer recipients may sign up to receive their second shots earlier than planned — yet those who took AstraZeneca and want to switch are being told to go to the back of the line.

“AstraZeneca people are being treated almost like second-class citizens,” said Mcwilliams. “It’s just not fair.”

Quebec Minister of Health and Social Services Christian Dubé said AstraZeneca recipients who want to switch vaccines have had to wait longer because doses of Moderna and Pfizer are in too short of supply.

He said the province is set to receive more doses of Moderna this week, and that an announcement regarding the status of AstraZeneca recipients will be made shortly.