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 4
Vaccine effectiveness against breakthrough SARS-CoV-2 infection of any severity, 2 or 3 doses versus unvaccinated, Western Australia, Australia, February 1, 2022–May 31, 2022*
| Case-patients |
Controls |
Vaccine effectiveness, % (95% CI)† | |||
|---|---|---|---|---|---|
| Vaccinated | Unvaccinated | Vaccinated | Unvaccinated | ||
| 16,306 | 6,060 | 17,292 | 5,074 | 24.9 (21.2–28.4) | |
| 103,741 | 14,299 | 108,863 | 9,177 | 42.0 (40.2–43.6) | |
*Case-patient (SARS-CoV-2 positive) and control (SARS-CoV-2 negative) pairs (infection status determined by PCR) matched by age group, sex, Aboriginality, testing week, Index of Relative Socioeconomic Advantage and Disadvantage decile and comorbidities. †Vaccine effectiveness = 1 − adjusted odds ratio (ascertained by using conditional logistic regression of matched pairs).
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