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COVID-19 vaccine effectiveness against lab-confirmed COVID-19 hospitalization using syndrome negative (SN) controls, by vaccine product, in Chile and Brazil. Latin America, 2021. Adjusted for continuous age, sex, secondary administrative unit location of residence, date of hospitalization grouped into categorical epiweeks, presence of 1 or more comorbidities, and study site country. Error bars show the 95% confidence intervals. TND = test-negative design.
