Volume 29, Number 6—June 2023
Research
SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022
Lauren E. Bloomfield, Sera Ngeh, Gemma Cadby, Kate Hutcheon, and Paul V. Effler
Table 5
Vaccine effectiveness against severe COVID-19, 2 or 3 doses versus unvaccinated, Western Australia, Australia, February 1, 2022–May 31, 2022*
| Vaccination status | Case-patients, hospital admission or death |
Controls |
Vaccine effectiveness, % (95% CI)† | |||
|---|---|---|---|---|---|---|
| Vaccinated | Unvaccinated | Vaccinated | Unvaccinated | |||
| Two doses | 131 | 69 | 148 | 52 | 41.9 (4.8–64.5) | |
| Three doses | 795 | 259 | 982 | 72 | 81.7 (73.9–87.2) | |
*Severe disease was defined as hospitalization for SARS-CoV-2 infection with 7 d of positive SARS-CoV-2 PCR results and/or death from any cause. †Vaccine effectiveness calculated with conditional logistic regression by using case–control pairs matched by week of testing, age group, sex, Aboriginality, Index of Relative Socioeconomic Advantage and Disadvantage, and comorbidity score.
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