Immunity from the measles vaccine declines significantly over time, with 18.1% of recipients lacking detectable antibodies 23 years after vaccination.
A study published Nov. 3 in eClinicalMedicine, the open access journal of The Lancet, by researchers from the University of Miami analyzed 18 studies involving 23,236 vaccinated individuals across 10 countries. The researchers found that the overall pooled seropositivity rate was 87.8%, with higher rates among those who received two or more doses (88.8%) compared to a single dose (84.3%).
Immunity declined steadily over time: 7.1% lacked antibodies 10 years after vaccination, 13% at 15 years, and 18.1% at 23 years or later. Each additional year post-vaccination was linked to a 5% decrease in the odds of being seropositive.
