Update on COVID-19 vaccine effectiveness

On December 7th, the Ontario Science Table, which is made up of scientific experts and health leaders who evaluate and report on emerging evidence relevant to the COVID-19 pandemic, released updated information on COVID-19 vaccine effectiveness. 

Here are some of the key points that were included in their update:

Compared to the fully vaccinated, unvaccinated individuals have a:

  • 5-fold higher risk of symptomatic disease,
  • 13-fold higher risk of being hospitalized, and
  • 23-fold higher risk of being in the ICU.

This is demonstrated in the first graphic, which compares the cases, hospitalizations and ICU admissions of unvaccinated individuals (orange line) vs. vaccinated individuals (blue line) over time. 

As shown in the second graphic, 8 months after becoming fully vaccinated (2 doses of Pfizer and/or Moderna), the vaccine remains:

  • over 95% effective against hospitalization and death,
  • close to 90% effective against symptomatic infection and,
  • over 70% effective against any infection (with or without symptoms).

That said, COVID-19 vaccination continues to be very effective, even now that the Delta variant is the dominant strain in Ontario.

Note: many things are still unknown about the Omicron variant (e.g. if it spreads more easily and the severity of illness), so we don’t know how much protection the vaccine will provide against this variant, but it does appear that booster doses may help maintain protection.