Jun 15, 2021
By Jane Brown
Scientists in England have concluded even one dose of the Pfizer-BioNtech and Oxford-AstraZeneca COVID-19 vaccines are extremely good at keeping people from ending up in hospital if they contract the Delta variant of the virus.
This is particularly welcome news in Canada, and here in the GTA, where the Delta variant is becoming dominant.
The study found after one dose Pfizer was 94 percent effect against hospitalization related to the COVID Delta variant and AstraZeneca’s shot is 71 percent effective. And after two doses, both vaccines are more than 90 percent effective against hospital stays linked to the Delta Variant.
Earlier research from Public Health England, released last month, suggested a single dose of Pfizer or AstraZeneca was only about 33 percent effective at preventing symptomatic cases of the Delta variant after one dose, but after two doses that rose to 88 percent for Pfizer and 60 percent for AstraZeneca.
Ontario’s Associate Medical officer of Health is commenting on the research and how this will play into herd immunity in this province.
“What achieves herd immunity, I don’t think there’s a really good answer to that. In general, we used to say 75 to 80 percent vaccine coverage, but again with Delta we’re not sure. Certainly, the best is to have everybody vaccinated and everybody vaccinated twice,” Dr. Barbara Yaffe explained during Monday afternoon’s media briefing.
Yaffe also points out the Delta variant is 1.5 times more transmissible than the original Alpha variant of COVID-19, all the more reason, she says, to keep up public health measures like masking and distancing.