Comparison of the effectiveness of four SARS-COV-2 v accines in Nuevo Leon, Mexico: A test-negative control study

OBJECTIVE: The objective of the present study was to provide statewide estimates of real-world effectiveness in reducing the odds of one primary (symptomatic COVID-19 infection) and two secondary outcomes (hospitalization and severe COVID-19 infection) by four vaccines BNT162b2 (Pfizer-BioNTech), ChAdOx1 (AstraZeneca), Ad5-nCoV (CanSinoBIO), and CoronaVac (Sinovac Life Sciences), used in Northeast Mexico. DESIGN: We conducted a test-negative case-control study and analyzed statewide surveillance data from December 2020 to August 2021. SITE: Primary attention and hospitalization. PARTICIPANTS: Two inclusion criteria were applied, age ≥ 18 years and having a real-time reverse-transcriptase-polymerase-chain-reaction assay or a rapid test for antigen detection in postnasal samples (N = 164,052). The vaccination was considered complete if at least 14 days had passed since the application of the single or second dose and the beginning of symptomatology. INTERVENTIONS: Does not apply. MAIN MEASUREMENTS: Point and 95% confidence intervals (CI) of vaccine effectiveness were calculated per type of vaccine using the formula 1 – odds ratio, adjusted by sex and age. RESULTS: Complete vaccination offered from none (CoronaVac – Sinovac) to 75% (95%CI 71, 77) (BNT162b2 – Pfizer) effectiveness in reducing symptomatic COVID-19 infection, regardless of sex and age. The fully ChAdOx1 (AstraZeneca) scheme reached the maximum effectiveness in hospitalization (80%, 95%CI 69, 87) and the fully BNT162b2 (Pfizer) scheme the maximum effectiveness in severity (81%, 95%CI 64, 90). CONCLUSIONS: More studies are needed to compare benefits of different vaccines and guide policy makers select the best option for their population.