Canada’s National Advisory Committee on Immunization (NACI) now says the maximum interval between the first and second doses of the Pfizer-BioNTech vaccine should increase from three weeks to four months.
“NACI recommends that in the context of limited COVID-19 vaccine supply, jurisdictions should maximize the number of individuals benefiting from the first dose of vaccine by extending the second dose of COVID-19 vaccine up to four months after the first,” the committee said in a statement.
Prior to this new recommendation, NACI had said that the maximum interval between the first and second shots of the Moderna vaccine should be four weeks, the interval for the Pfizer-BioNTech product should be three weeks and the interval for the Oxford-AstraZeneca vaccine should be 12 weeks.
“While studies have not yet collected four months’ of data on vaccine effectiveness after the first dose, the first two months of real world effectiveness are showing sustained high levels of protection,” NACI said.
Since first doses of all three vaccines have been shown to dramatically increase immunity to the disease, or to significantly reduce the illness associated with contracting COVID-19, the committee said stretching the interval would help protect more Canadians sooner.