TOPLINE:

Individuals who received a measles-containing vaccine (MCV) had high seropositivity for the first decade after vaccination. However, immunity waned over time, with 7.1% of individuals lacking detectable antibodies at 10 years and 18.1% at 23 years or later.

METHODOLOGY:

• Researchers conducted a systematic review and meta-analysis to assess the prevalence of measles seropositivity and changes in antibody levels over time in vaccinated individuals.
• They included data from 18 studies published between 1994 and 2024 that involved 23,236 vaccinated individuals from 10 countries.
• The primary outcome was overall measles seropositivity in individuals who had received at least one dose of an MCV, and the secondary outcome was the change in measles seropositivity over time since vaccination.
• Seropositivity (defined as the proportion of individuals testing seropositive after receiving at least one dose of an MCV) was determined at a specified timepoint in participants aged 1 year or older at the time of serologic testing.

TAKEAWAY:

• The overall pooled measles seropositivity was 87.8% (95% CI, 83.9%-91.2%). The pooled seropositivity was 84.3% in those who received a single dose (six studies) compared with 88.8% in those who received two or more doses (15 studies).
• Seropositivity declined continuously over time, with the pooled seropositivity being 92.9% at 0-10 years post-vaccination, 87.0% at 11-15 years post-vaccination, 82.8% at 16-22 years post-vaccination, and 81.9% at 23 years or later post-vaccination.
• Time since vaccination was the strongest predictor of seropositivity; each additional year after vaccination was associated with 5% decrease in the odds of being seropositive (P < .001).

IN PRACTICE:

“[Our] findings suggest that while two doses confer stronger initial seropositivity, additional strategies may be needed to sustain long-term seropositivity induced by measles vaccination,” the authors wrote.

“Targeted serological screening could be considered for high-risk groups, including healthcare workers, international travelers, and adults born during periods of suboptimal vaccine coverage,” they added.

SOURCE:

This study was led by Mohammed Mustafa, University of Miami, Miami. It was published online on November 03, 2025, in eClinicalMedicine.

LIMITATIONS:

Measles-specific immunoglobulin G antibodies were imperfect surrogates for clinical protection as individuals with undetectable antibodies may still be protected by cellular immunity or anamnestic responses. Most studies were cross‑sectional, preventing the direct observation of within‑person antibody kinetics, and the heterogeneous reporting of vaccination information limited the assessment of effects by factors such as age at vaccination or vaccine formulation. Variable seropositivity thresholds across assay platforms may have posed challenges for direct comparisons of results.

DISCLOSURES:

This study did not receive any funding. One author reported receiving a National Institutes of Health training grant. Another author reported receiving an internal grant award from the University of Miami, and another reported receiving a research grant, consulting fees, and honoraria for lectures from various pharmaceutical companies and being an executive committee member of two professional transplantation societies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.