A systematic review and meta-analysis in eClinicalMedicine concluded that hepatitis A vaccines prevent about 96% of infections when given before exposure and about 97% when administered after exposure. The analysis, described as the largest quantitative evidence synthesis to date, evaluated vaccine performance for both pre- and post-exposure use. The results feed directly into outbreak-control planning, where rapid post-exposure vaccination can still reduce transmission even when exposure has already occurred. The findings support current immunization strategies while providing updated effect sizes for guideline committees. For biopharma and public health stakeholders, the quantified protection levels help frame demand and procurement decisions during seasonal or outbreak-driven surges.