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.