'It's hard to tell:' Some potentially given saline instead of COVID-19 vaccine

Marnin Heisel isn't sure whether he received a saline dose, or a Pfizer-Biontech COVID-19 vaccine when he attended a St. Thomas, Ont. clinic for his booster shot.

"I had no reaction from the shot and then had a little bit of pain in the arm," says Heisel, who attended the Southwestern Public Health (SWPH) vaccine clinic on Nov. 30, 2021 at the St. Thomas-Elgin Memorial Arena.

"If you were to ask me do I think I got the full vaccine or do I think I got saline before my arm started hurting? I might have said nothing afterwards but It's really hard to tell."

Heisel received a call on his cell phone from someone at SWPH Tuesday evening, informing him there may have been a human error when he received his third dose.

Six people out of 257 who got their shot, or two percent, were not given their vaccine that day.

"A medication error is never something that we're proud of," says Dr. Joyce Lock, the medical officer of health for SWPH.

"The manufacturer sends it to us in a slightly concentrated form and then we have to dilute it down to get to the proper strength. And so then a little bit of salt water is added. At the end of the day, we reconcile the amount of little bottles of saline with the amount of vaccine doses and of course, at the end of the day, there should be equal numbers every single day. So we did that on that particular day. And we noticed, we're out," she explains.

This isn't the first time this has happened across the country. It's been reported by multiple health units in Ontario and Alberta.

The clinic is now reconciling every hour instead to potentially impact a smaller number in case there is an error. SWPH is also changing out staff who have been doing the same job for hours to avoid a lapse in concentration.

With advice from Public Health Ontario (PHO), SWPH elected not to inform those at the clinic that day until Tuesday, Dec. 21, or after the recommended 21 day period.

Marnin Heisel speaks via Zoom on Wednesday, Dec. 22, 2021.

Heisel, who is a clinical psychologist and an associate professor at Western University's Schulich School of Medicine and Dentistry, offers a different opinion.

"If they believe that they've been triple vaxxed, if they believe they've been boosted and as a result, have a higher level of immunity," says Heisel. "People might start relaxing some of their health behaviours. That's something I think they should think ahead to in the future in situations like this, but aside from that, I think that they handled it extremely well."

Lock tells CTV News London there are a few reasons they waited 21 days to inform those who attended that day.

"We did know that most of these people already have previous doses of vaccine and so that they did have immunity on board," says Lock.

"We also knew that if we told them early, we were concerned that they might inadvertently end up booking their repeat dose soon and it is safer and better to be sure that you have at least 21 days between that dose and disclose that you are getting an extra fourth dose."

With consultation from PHO, they also will not change the date of the inoculation. Those who get a fourth dose from the mix-up will still have their third dose date as Nov. 30.

SWPH says some people experienced symptoms from their shot last month and are certain they got vaccine, so they won't be returning to get another dose.

Heisel, along with a number of others who aren't sure if they received the vaccine, will return to get a potentially fourth shot.

Lock believes for them, it will only strengthen their immune system, "Definitely no harm, if anything benefit from the additional dose."

She adds, "Ontario is actually beginning to contemplate and giving out fourth doses for our most vulnerable like our seniors, so a few people in our neck of the woods got are getting ahead with a fourth dose."