Evaluating the effectiveness of the mpox vaccine: Insights from real-world data

The effectiveness of vaccines plays a crucial role in public health, determining their ability to prevent infection, reduce disease severity, and limit transmission within communities. A recent study examined how well the modified vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine protects against mpox, particularly in higher-income countries where it was rapidly deployed in 2022. Given the absence of randomized controlled trials (RCTs), the study relies on observational data to assess the vaccine’s real-world impact. Understanding vaccine effectiveness Vaccines can have multiple effects on disease prevention, categorized into direct effects, indirect effects, and herd immunity. Direct effects refer to how well a vaccine protects an individual from infection and severe disease. Indirect effects occur when vaccination reduces the ability of infected individuals to transmit the disease to others, thereby lowering infection risks for both vaccinated and unvaccinated individuals. Herd immunity, a population-level effect, emerges when widespread vaccination reduces the overall number of susceptible individuals, decreasing...