A new study in England suggests the Pfizer-BioNTech and Oxford-AstraZeneca vaccines are extremely good at keeping people from ending up in the hospital with COVID-19, even after just one dose.
Public Health England says it looked at the records of 14,000 people with confirmed cases of COVID-19 due to the Delta variant between April 12 and June 4.
It found two doses of either vaccine were more than 90 per cent effective at keeping people out of the hospital.
After one dose, Pfizer was 94 per cent effective against hospitalization, and AstraZeneca's vaccine was 71 per cent effective.
Ontario infectious disease specialist Dr. Isaac Bogoch says the study is a ray of hope at a time when "good news is in short supply."
Canada's strategy of getting first doses into the arms of as many people as possible before moving on to second doses has been controversial.
An earlier study from Public Health England suggests a single dose is far less effective than both doses at preventing symptoms from COVID-19.
Almost two in three Canadians now have one dose of vaccine, but slightly more than one in 10 have both doses.
Canada is pivoting to second doses rapidly however, with 1.2 million people joining the fully vaccinated group just in the last four days.