CLAIM: A bus advertisement on knowing the warning signs of strokes in children is related to COVID-19 vaccines.

THE FACTS: In the days after the U.S. Food and Drug Administration cleared a smaller dose of the Pfizer vaccine to be used by children ages 5 to 11, social media users shared a photo of a bus advertisement from Canada to spread false information about COVID-19 vaccines and children. Posts that circulated online included a photo of the advertisement, which read, “Kids have strokes too, know the signs,” along with a caption that falsely suggested that the government was somehow forecasting a wave of strokes among children once they become vaccinated against COVID-19.

However, the advertisement, which was featured on nine buses in Ontario, has no link to the vaccines. A Canadian charitable foundation, Achieving Beyond Brain Injury, placed the ads to educate the public about strokes among children during Pediatric Stroke Awareness month in May.

The foundation’s co-founders, Nadine Vermeulen and Rebecca DiManno, started the organization after their sons suffered strokes at 10 and 14 years old. Vermeulen said the bus ads had nothing to do with the COVID-19 vaccines.

“It was heartbreaking that what we are trying to do and spread awareness has been turned into something that we feel we have to defend ourselves against,” she said about the claims on social media. Vermeulen said her organization had not said that strokes are common, they only wanted to make parents aware. “Neither of us knew that kids could have strokes until our kids did,” Vermeulen told The Associated Press. “There are different signs you can look for that can help save a child’s life.”

The Centers for Disease Control and Prevention does not list stroke as a side effect of the COVID-19 vaccines. Millions of children ages 12 to 17 have received the Pfizer vaccine and there have been no significant reports of strokes.

“None of the mRNA vaccines that are under investigation for children are associated with that,” Dr. Kevin J. Downes, assistant professor of pediatrics at the University of Pennsylvania’s Perelman School of Medicine, said of strokes.

This week, American children aged 5 to 11 began receiving Pfizer’s COVID-19 vaccine for kids. Prior to that, the FDA reviewed data from 3,100 children in that age group who had received the vaccine during trials and found that some experienced mild to moderate side effects, including sore arms, fatigue and fever. In rare cases, some teens and young adults who have received the Pfizer or Moderna vaccines have reported a side effect of heart inflammation also known as myocarditis.

— Associated Press writer Beatrice Dupuy in New York contributed this report.