If you've had a COVID-19 vaccine, you'll be familiar with the provincial government document that states when the vaccination occurred and what shot was administered.
But Windsorite Rishabh Agarwal has two receipts for his first dose that he received this past weekend, each referencing a different vaccine, and he isn't sure which shot actually went into his arm.
Agarwal isn't concerned about the brand of vaccine he received but is concerned about what happens next.
"My fear is, how can I take a second dose if I didn't know what was given to me in the first place? So, that's the fear," he said.
Agarwal said he received a vaccine at a drive-in clinic at a doctor's office. Initially, he said was told the clinic was administering the shot made by Moderna, but the person who gave him the jab said he was being injected with the Pfizer-BioNtech vaccine.
Later, he approached another volunteer who told him the clinic was administering both shots.
Later in the afternoon, after he received a provincial government vaccination record that said he received Moderna — in the incorrect arm — Agarwal said he contacted the clinic.
According to Agarwal, a receptionist told him he received Pfizer and a new certificate was issued. He provided a copy of both certificates to CBC News.
CBC News has reached out to the Windsor clinic where Agarwal received his shot on Tuesday and is awaiting clarification from the physician in charge.
Ontario's Ministry of Health and Long-Term Care said in a statement that vaccine administrations are reviewed routinely during clinic operation checks.
"When an error such as the one referenced is noted, the record is corrected. This can result in a second automatic receipt being sent to the same vaccine recipient," a spokesperson said.
The Windsor-Essex County Health Unit (WECHU) said it would not speculate on what occurred at a health-care practitioner-led vaccination clinic without speaking directly to the operator first.
WECHU CEO Theresa Marentette did say Tuesday that operators and their volunteers are only trainined to use the vaccine administration database.
"There is training for entering all the vaccine into the COVAX system. There's no other training because these are physicians and primary care providers, so they would know how to administer the vaccine. Their strategy and their method of delivery, we don't have oversight over that or an approval process."
According to the the health unit, people who receive COVID-19 vaccines are supposed to be informed of what vaccine they are receiving.
"Any time you're receiving a vaccine or any medication ... you're entitled to be informed. You've giving consent for the vaccine so it's important," she said.