Seroprevalence of measles, mumps and rubella specific antibodies in the population of Slovakia: One vaccine, three different patterns

Measles, mumps, and rubella (MMR) rank among highly contagious diseases that present significant public health challenges despite availability of effective vaccines. In Slovakia, mass vaccination against these infections has historically maintained high coverage (over 95 %), although a gradual decline has been observed since around 2010 due to anti-vaccination activities. This trend creates concerning immunity gaps, risking disease resurgence. While vaccination has suppressed MMR in Slovakia, isolated outbreaks of measles and mumps have occurred, primarily in unvaccinated populations, unlike rubella, which has seen no significant epidemics since widespread vaccination. This study aimed to describe the seroprevalence of MMR antibodies in the Slovakian population, compare their immunological profiles, and identify potential risk groups. A cross-sectional serosurvey conducted in 2018 analyzed blood samples from 4218 individuals aged 1-69 years. Specific IgG tests determined respective antibody levels. Overall seropositivity rates were 91.7 % for measles, 75.6 % for mumps, and 95.9 % for rubella. For measles, antibody levels were highest in the oldest cohorts, with a clear decline observed after initiation of vaccination. Seropositivity was significantly lower in vaccinated cohorts compared to those with assumed natural infection. Mumps seropositivity was considerably lower than for measles and rubella. While mumps antibody trends were less pronounced, seropositivity in cohorts with natural disease overcoming was higher than in mixed or single-dose vaccinated cohorts (OR = 1.99 and 1.82 respectively). Rubella showed very high overall seropositivity across all age groups. Antibody levels for rubella also showed a sharp decline after the first dose (10.7 % per year) and a less pronounced decline after the second dose (3.5 % per year). The study concludes that maintaining high, two-dose MMR vaccination coverage is crucial for outbreak prevention. Continuous serosurveillance is essential to identify and address immunity gaps in specific cohorts, thereby supporting MMR elimination efforts.