Peer-reviewed article
Seroprevalence against measles, Austria, stratified by birth years 1922 to 2024.
Springer DN, Borsodi C, Camp JV, Redlberger-Fritz M, Holzmann H et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study analysed measles immunity in Austria by measuring antibodies in over 56,000 samples collected between 2010 and 2024, stratified by birth year. People born before 1970 maintained strong immunity, but those born after 1990 showed seronegativity rates of 13-20% and lower antibody levels, indicating immunity gaps in younger populations. These gaps existed before the COVID-19 pandemic and did not worsen during it. The findings show that vaccination of young and middle-aged adults is needed to prevent measles outbreaks.
Key points
- Individuals born before 1970 had high antibody levels (>3,000 IU/L) with <2% seronegative
- Individuals born after 1990 had seronegativity rates of 13-20% and lower median antibody concentrations (449-773 IU/L)
- Immunity gaps in younger populations pre-existed before the COVID-19 pandemic
- No significant difference in seronegativity rates in children aged 12-24 months born during 2016-2019 versus 2020-2022
- Large measles outbreaks occurred in Austria in 2023 and 2024 despite achievement of elimination status in 2018
Limitations
This is a retrospective analysis of diagnostic samples which may not represent the general population equally; the study cannot determine why immunity gaps exist in younger cohorts (e.g., vaccine uptake rates, vaccination timing, or waning).
Abstract
BackgroundVaccination programmes initiated in the early 1970s reduced the incidence of measles in Austria, which resulted in the interruption of endemic measles virus (MeV) circulation and the achievement of elimination status in 2018. However, large outbreaks occurred in 2023 and 2024.AimBy assessing MeV-specific IgG antibody levels, we analysed if immunity recently declined due to the COVID-19 pandemic, vaccine-induced immunity waned over long term or immunity gaps already pre-existed in the population.MethodsWe determined anti-MeV antibody levels in a retrospective dataset of 56,360 diagnostic samples (from 50,754 individuals) collected 2010-2024 and correlated antibody cutoffs to titres from a live-virus neutralisation test.ResultsIndividuals born before 1970 (n = 15,007) had antibody levels > 3,000 IU/L, persisting into higher age, and < 2% (n = 300) of them were seronegative. In contrast, individuals born after 1990 (n = 12,778) displayed seronegativity rates of 13-20% and lower median antibody concentrations in seropositive individuals (449-773 IU/L). In these individuals, antibody levels decreased noticeably between the ages of 2 and 10 years but remained stable between those aged 10 and 30 years. There was no significant difference in seronegativity rates at the age of 12-24 months in children born 2016-2019 and 2020-2022 (the years of the COVID-19 pandemic).ConclusionIn Austria, there are significant immunity gaps in individuals born after 1970, which pre-existed before the COVID-19 pandemic. Thus, young and middle-aged populations not immune against measles should be vaccinated to counteract a further decline of immunity at the population level and prevent outbreaks whenever MeV is imported.
Findings the Hub has extracted
Each claim below is labelled by its type of design and links back to this report.
Problem
Measles outbreaks in Austria in 2023-2024 after measles elimination status was achieved in 2018
- Intervention
- Analysis of population immunity against measles through serological testing to identify immunity gaps
- Population
- 56,360 diagnostic samples from 50,754 individuals in Austria, stratified by birth year from 1922 to 2024
Key finding
Pre-1970 cohort: <2% seronegative with antibody levels >3,000 IU/L persisting with age