It started just days after she received her second dose of Pfizer COVID-19 vaccine. Red, blistering spots that were painful and burned began showing up on her legs. Within weeks, she was in the hospital, unable to walk because of the pain.

Sixty-one-year-old Bonnie Keefe of Renfrew is one of about a dozen Canadians believed to have suffered from cutaneous vasculitis — inflammation of small blood vessels that can cause painful skin lesions — most likely associated with a COVID-19 vaccination.

It is considered an “adverse event of special interest” by the Public Health Agency of Canada, which tracks all adverse reactions to the vaccines — serious and less serious.

Such reactions are rare and evidence grows daily about how well the vaccines work at preventing serious illness and hospitalization from COVID-19.

But that is little comfort to Keefe.

She doesn’t want to discourage people from getting vaccinated. “I am just one of those cases that fell through the cracks.” But she does want people to know just how serious those rare reactions can be.

“I cry every night,” Keefe said. “I just wish I could be in less pain.”

In total, 2,463 Canadians are known to have suffered adverse events of special interest linked to COVID-19 vaccines, according to the Public Health Agency of Canada. Myocarditis and pericarditis — inflammation of the heart muscle or lining of the heart — have been the most common serious adverse events, affecting 557 people.

Those serious reactions are out of nearly 27 million Canadians who have received at least one dose of a COVID-19 vaccine. Adverse events are rare and the risks from COVID-19 — especially now that the Delta variant is dominant — are great.

A recent Israeli study, for example, found that myocarditis is more common after COVID-19 than after a Pfizer vaccine. The COVID-19 vaccine from Pfizer has been linked to an increased risk of myocarditis and pericarditis. But the risk from an infection is higher.