COVID-19 vaccinations, due to a stable supply of vaccines, prioritizing those aged 80 and older. Officials also said Ontarians will be fully vaccinated by the end of summer.In documents released Friday, officials said second shots of Pfizer and Moderna can be done earlier based on the date of their first dose — a strategy they are calling “first-in, first-out.”When it comes to the new dosage interval, Ontario officials said it could be as short as 28 days — meaning those eligible for an accelerated second dose appointment must have had their first shot at least 28 days prior.Ontario said people 80 years and older can start to reschedule for an earlier appointment starting Monday, May 31.The 70 and older age band can book an earlier.