Mumps in Poland in 2024
Abstract
Mumps is an acute viral disease transmitted via respiratory droplets, with humans as the only reservoir. Infection spreads easily among children and adolescents, and infectiousness begins before symptom onset. The introduction of MMR vaccination within the mandatory National Immunisation Programme in Poland in 2003 markedly reduced the number of cases and complications.However, surveillance remains essential for evaluating programme effectiveness and the current epidemiological situation. To evaluate the epidemiological situation of mumps in Poland in 2024 in comparison with previous years. The analysis was based on data published in the annual bulletins: "Infectious diseases and poisonings in Poland in 2024" and "Vaccinations in Poland in 2024" as well as individual case data from the EpiBaza system. Vaccination coverage for the first dose was assessed using data for the 2022 birth cohort (children in their 3rd year of life), and for two doses using data for the 2018 birth cohort (children aged 6 years). Vaccine effectiveness was estimated using the screening method. In 2024, 931 mumps cases were reported (3.6% decrease vs. 2023: 966). Overall incidence was 2.5 per 100,000 (in 2023: 2.6) and remained below the 2015-2019 median (4.3). The highest incidence was recorded in Śląskie voivodeship (3.7; 159 cases), and the lowest in Opolskie and Warmińsko-Mazurskie voivodeships (1.0). The largest numbers of cases were reported in Mazowieckie (183) and Śląskie (159) voivodeships. Eighteen patients were hospitalised (vs. 12 in 2023). Laboratory testing was performed in 2.1% of cases. In 2024, a slight decrease in the number of cases was observed, with incidence similar to 2023. Values remained lower than in the pre-COVID-19 period. The increase in case numbers after 2021 may be associated with the restoration of social contacts and transmission of droplet-borne infections. The low proportion of hospitalisations does not indicate increased clinical severity. Continued monitoring of trends and case structure is justified, together with improving the proportion of laboratory confirmation.