COVID-19: Lineup for walk-in Pfizer vaccinations spans blocks in Osborne Village Cassie doesn’t know who cancelled their appointment, or for what reason, but she has a feeling that person was over the age of 18 and decided to go for a Moderna shot instead.Since the only COVID-19 vaccine approved for people under the age of 18 in Canada is the Pfizer vaccine, Cassie’s mom, Avril French Varga, said she had a couple friends cancel their Pfizer appointments with the intention of opening spots for youth.French Varga is grateful that some adults are making switch.“We see the impact it’s (the pandemic) having on kids,” she said. “The faster we all do it (get vaccinated) the faster we can get through this.” Some Canadians denied Moderna COVID-19.