Four residents receive AstraZeneca shots in ‘error’ after COVID-19 vaccine mixup in Hamilton

A resident has filed a complaint after being identified as one of four people to receive an AstraZeneca dose in error" at a Hamilton clinic on Wednesday afternoon.

Staff at the David Braley Health Sciences Centre on 100 Main St. W. discovered four individuals had mistakenly received AstraZeneca for their second doses instead of Moderna.

This was definitely an error for which we're deeply sorry," said Dr. Cathy Risdon, lead physician for the McMaster Family Health Team, which is supporting the primary care clinic.

The clinic is offering doses of both vaccines, and vials were kept in differently coloured bins with labels of different colours to help keep them separate, she said.

One of the vaccinators was working diligently and mistakenly grabbed a set of vaccines from the wrong bin," Risdon said. The individual administered four doses before realizing the error.

The clinic was suspended" to determine who had received those shots. Three of the recipients were in the waiting area and informed on-site, while one person was informed by phone, Risdon said.

Two of the individuals were in their 20s, one in their 30s and one in their 60s, she added. Three of the recipients had received a mRNA vaccine for their first dose.

Jeffrey H. was stunned" to learn he received AstraZeneca instead of his second dose of Moderna. He didn't want his full name published to keep his medical records private. In an interview, the 31-year-old structural engineer said he filed a complaint with the College of Physicians and Surgeons of Ontario.

My main concern with all this was consent," said Jeffrey. I was injected with something I did not give permission for."

Though he doesn't believe the mistake was intentional, he wants to ensure it doesn't repeat. Thursday afternoon, he didn't have any side effects other than fatigue and muscle pain.

My aim here is not to discourage people from getting vaccinated, I think it's still incredibly important," he said. If I saw an article like this, I would have probably asked to double-check (the label) before I got an injection."

Before halting first doses of AstraZeneca, Ontario limited the age for the vaccine to 40-plus. (The National Advisory Committee on Immunization (NACI) set the age minimum at 30, while Health Canada approved the vaccine for anyone 18-plus.)

Currently, those who received AstraZeneca can get the same vaccine or a mRNA shot for their second dose. The reverse is not an option.

Our current understanding of mixing the two types of vaccine is that it produces a very robust immune response," Risdon said. We don't have a lot of experience with starting with a mRNA and ending with an AstraZeneca."

In Canada, the risk of rare blood clots, called vaccine-induced immune thrombotic thrombocytopenia (VITT), is around one in 55,000 for one dose of AstraZeneca. The risk drops for the second dose, which a U.K. study found to be about one in 600,000.

We're in relatively uncharted territory because we haven't seen this particular order," Risdon said, though she believes the recipients will still have an excellent immune response and be considered fully vaccinated" even if they got a mRNA dose first.

In an email, a University of Toronto professor and head of clinical pharmacology and toxicology said he suspected recipients would be at the same (very low) risk of VITT as people who received one dose" of AstraZeneca.

Asked about the effect on recipients' immune response, Dr. David Juurlink said, I'm not sure, but my guess is they will be well protected against severe COVID, as someone who gets (AstraZeneca) followed by Moderna would be."

Dr. Dominik Mertz, associate professor in the division of infectious diseases at McMaster University, said he's not aware of clinical data on people who received AstraZeneca after an mRNA vaccine.

As such we can only hypothesize whether the level of protection and risks are comparable," he said in an email.

Hamilton's medical officer of health said NACI hasn't provided advice on this interchangeability."

We would anticipate based on what we do know that there would be a boosting of the immune response to COVID-19 and its variants," Dr. Elizabeth Richardson said in an email statement, adding that it's important to know the signs of VITT and seek prompt" medical care if they arise.

Risdon said the four patients were to receive calls Thursday to address any questions and ensure they know how to monitor for symptoms. She expects the clinic will complete its AstraZeneca offerings by Monday, and only offer Moderna after that.

In the meantime, the clinic is taking more measures as a safeguard. The vaccines are being kept very separate," Risdon said. Patients will also receive a sticker the same colour of the label on their intended vaccine, so they'll be a bit more involved in helping do that double-check."

Injections will be delivered to vaccinator instead of having them pick them up from a bin themselves. That way, they can focus only on administering the shots.

I'm very confident that we're not going to run into this situation again," Risdon said.

- With files from Fallon HewittMaria Iqbal is a Hamilton-based reporter at The Spectator covering aging issues.