Your browser doesn't support javascript.
Effectiveness of Four Vaccines in Preventing SARS-CoV-2 Infection in Kazakhstan
Open Forum Infectious Diseases ; 9(Supplement 2):S863-S864, 2022.
Article in English | EMBASE | ID: covidwho-2190011
ABSTRACT
Background. In February 2021 Kazakhstan began offering COVID-19 vaccines to adults. Breakthrough SARS-CoV-2 infections raised concerns about real-world vaccine effectiveness. We aimed to evaluate effectiveness of four vaccines against SARS-CoV-2 infection. Methods. We conducted a retrospective cohort analysis among adults in Almaty using aggregated vaccination data and individual-level breakthrough COVID-19 cases (>=14 days from 2nd dose) using national surveillance data. We ran time-adjusted Cox-proportional-hazards model with sensitivity analysis accounting for varying entry into vaccinated cohort to assess vaccine effectiveness for each vaccine (measured as 1-adjusted hazard ratios) using the unvaccinated population as reference (N=565,390). We separately calculated daily cumulative hazards for COVID-19 breakthrough among vaccinated persons by age and vaccine month. Results. From February 22 to Sept 1, 2021 in Almaty, 747,558 (57%) adults were fully vaccinated (received 2 doses) and 108,324 COVID-19 cases (11,472 breakthrough) were registered. Vaccine effectiveness against infection was 78% (sensitivity estimates 74-82%) for QazVac, 77% (72-81%) for Sputnik V, 71% (69-72%) for Hayat-Vax, and 69% (64-72%) for CoronaVac. Among vaccinated persons, the 90-day follow-up cumulative hazard for breakthrough infection was 2.2%. Cumulative hazard was 2.9% among people aged >=60 years versus 1.9% among persons aged 18-39 years (p< 0.001), and 1.2% for people vaccinated in February-May versus 3.3% in June-August (p< 0.001). Conclusion. Our analysis demonstrates high effectiveness of COVID-19 vaccines against infection in Almaty similar to other observational studies. Higher cumulative hazard of breakthrough among people >60 years of age and during variant surges warrants targeted booster vaccination campaigns. (Figure Presented).
Keywords

Full text: Available Collection: Databases of international organizations Database: EMBASE Type of study: Experimental Studies Topics: Vaccines Language: English Journal: Open Forum Infectious Diseases Year: 2022 Document Type: Article

Similar

MEDLINE

...
LILACS

LIS


Full text: Available Collection: Databases of international organizations Database: EMBASE Type of study: Experimental Studies Topics: Vaccines Language: English Journal: Open Forum Infectious Diseases Year: 2022 Document Type: Article