AstraZeneca and Oxford University's COVID-19 vaccine is more effective when its second dose is given three months after the first, instead of six weeks, a peer-reviewed study published in The Lancet medical journal showed on Friday. The study confirmed the Anglo-Swedish drugmaker's findings from earlier this month that showed the vaccine had 76 per cent efficacy against symptomatic coronavirus infection for three months after the first dose. Canada has not yet approved the AstraZeneca-Oxford shot, but is set to receive millions of doses if it is authorized by Health Canada. In the long term, a second dose should ensure long-lived immunity, and so we encourage everyone who has had their first vaccine to ensure they receive both doses." Some other vaccines, such as for flu, Ebola and malaria, also provide greater protection and stronger immune responses after a longer interval between doses.

Source: CBC News February 19, 2021 19:52 UTC