A CITF-funded study, published in the Canadian Journal of Emergency Medicine, found that substantially fewer patients were admitted to critical care and put on mechanical ventilation in the second wave of the pandemic than in the first – with no negative impact on mortality.
A CITF-funded study, published in Clinical Infectious Diseases, provided evidence that protection provided by COVID-19 vaccines and/or prior SARS-CoV-2 infections against severe outcomes is reduced when immune evasive SARS-CoV-2 variants and subvariants emerge.
A CITF-funded study, published in Cureus, examined the impact of different dosing intervals between the first two COVID-19 mRNA vaccines. Intervals longer than 38 days, compared to a short interval of less than 30 days, resulted in higher levels of SARS-CoV-2 anti-spike antibodies.
A CITF-funded study, published in The Journal of Infectious Diseases, reported that third and fourth doses of monovalent and bivalent mRNA vaccines provided similar strong protection against severe outcomes from COVID-19 among community-dwelling adults over the age of 50. However, further follow-up is needed to determine the long-term protection of bivalent vaccines and their effectiveness against newer Omicron variants.
CITF-funded studies show the important role that vaccines have played in protecting Canadians and people worldwide from severe COVID-19. Here, we summarize results from the five presentations given during the breakout session “Vaccine safety and effectiveness” at the CITF Scientific Meeting in Vancouver, March 8-10, 2023.
A CITF-funded study, published in preprint and not yet peer-reviewed, provided evidence that individuals with hybrid immunity (a combination of infection-acquired and vaccine-induced SARS-CoV-2 immunity) had nearly 90% protection against severe outcomes (hospitalization or death) during the Omicron BA.1/BA.2 and BA.4/BA.5 predominant periods.
A CITF-funded study, published in preprint and not yet peer-reviewed, found that a 2nd dose of the Moderna vaccine was associated with reduced symptomatic SARS-CoV-2 infection (vaccine effectiveness [VE]=90%), as well as reduced COVID-19-related hospitalization (VE=82%) in children aged 6 months to 5 years.
A CITF-funded study, published in JMIR Public Health Surveillance, found that self-reported COVID-19 vaccination status, when compared with the Québec Vaccination Registry as a reference standard, was accurate in 96% of cases.
A CITF-funded study, published in Scientific Reports, found that the proportion of incidental SARS-CoV-2 infections increased substantially across the pandemic waves. In particular, the percentage of people who tested positive for COVID-19 upon admission to hospital for something else rose from 10% to 41% during the Omicron wave.
A CITF-funded study, published in preprint and not-yet peer-reviewed, reported that third and fourth doses of monovalent and bivalent mRNA vaccines provided similar strong protection against severe outcomes from COVID-19 among community-dwelling adults over the age of 50.