Johnson & Johnson vaccine approval expected in ‘next few days’: feds This comes following Canada’s National Advisory Committee on Immunization (NACI) recommendations Wednesday that provinces and territories could extend the interval between first and second COVID-19 vaccine doses up to four months.“Extending the dose interval to four months allows NACI to create opportunities for protection of the entire adult population within a short timeframe,” the committee said.Njoo echoed the committee’s suggestions and said, “NACI bases data on evolving evidence in a real world context.”Several provinces across Canada have already given nod to the NACI advisory in order to fast-track the vaccination process.[ Sign up for our Health IQ newsletter.