OTTAWA—Canada could get more than one million additional doses of COVID-19 vaccine by the end of March through a global vaccine sharing initiative known as COVAX. But as with most things COVID-19, vaccine-related deliveries are mired in the uncertainty of regulatory reviews and potential production delays. The COVAX Facility, co-ordinated by the World Health Organization and Gavi, The Vaccine Alliance, pools funds from wealthier countries to buy vaccines for themselves and for 92 low- and middle-income nations that can’t afford to buy on their own. Canada contributed $440 million to COVAX in September, half of which secured doses for Canada directly, from about nine vaccines that are participating in the program. The other half goes into a pooled fund to buy doses for 20 percent of the people in 92 low- and middle-income countries. Procurement Minister Anita Anand tells The Canadian Press that up to 1.1 million doses of AstraZeneca’s …