An advisory panel at the U.S. Centers for Disease Control and Prevention (CDC) has recommended a third dose of the Pfizer-BioNTech COVID-19 vaccine for Americans aged 65 and older and for some adults with underlying medical conditions that put them at risk of severe disease. But the panel declined to make the same recommendation — an additional booster after the first two-shot combination — for adults ages 18 to 64 who live or work in institutions with a high risk of contracting COVID-19, based on individual risk, such as health-care workers, teachers and residents of homeless shelters and prisons.Some panel members cited the difficulty of implementing such a proposal. Still, the vote by the group on Thursday clears the way for a third dose roll-out to begin as soon as this week for millions of people who had their second Pfizer dose at least six months ago. The CDC said that some 26 million people in the United States fall in that timeframe, including 13 million seniors aged 65 or older. The new recommendations follow Wednesday's emergency use authorization from the U.S. Food and Drug Administration (FDA) for a booster shot of the Pfizer vaccine for seniors 65 and up and for certain adults at a high risk of severe COVID-19. Canada's national advisory body on vaccines currently recommends giving third doses of COVID-19 vaccines to certain immunocompromised individuals, but hasn't decided whether to provide additional shots to the broader population. The recommendations from the National Advisory Committee on Immunization (NACI) stipulate that moderately to severely immunocompromised Canadians should be vaccinated with a primary series of three doses of an authorized mRNA-based vaccine, which includes those from Pfizer-BioNTech and Moderna.
