Evaluation of BBIBP-CorV Sinopharm COVID-19 vaccine effectiveness in Sri Lanka: a test-negative case control study.

Objectives: There is limited research on real-world effectiveness of BBIBP-CorV Sinopharm COVID-19 vaccine. This study evaluated real-world effectiveness of Sinopharm vaccine in Sri Lanka by assessing absolute vaccine efficacy.

Design And Setting: A retrospective test-negative case-control study was conducted at ten large government hospitals across the country.