Measles Cases in England Consistent With Waning of Vaccine Immunity

Slow estimated waning rate of 0.039 percent per year of age was sufficient to increase measles burden



MONDAY, Sept. 30, 2024 (HealthDay News) — Measles cases in England are consistent with the waning of vaccine-induced immunity, according to a study published online Sept. 26 in The Lancet Public Health.

Alexis Robert, Ph.D., from the London School of Hygiene & Tropical Medicine, and colleagues examined whether measles dynamics observed in England between 2010 and 2019 were in line with waning of vaccine-induced immunity using a compartmental mathematical model stratified by age group, region, and vaccine status. The deterministic model was fitted under three scenarios: without waning of vaccine-induced immunity, with waning depending on time since vaccination, and with waning depending on time since vaccination starting in 2000.

The researchers found that the number of one-dose recipients among measles cases was overestimated in the scenario without waning, and the number of two-dose recipients was underestimated among cases older than 15 years (median, 75 cases in simulations without waning; 196 cases in simulations with waning; 188 cases in simulations when waning started in 2000; and 202 observed cases). The number of onward transmissions from vaccinated cases was 83 percent of transmissions from unvaccinated cases. There was a slow estimated waning rate (0.039 percent per year of age), but this was sufficient to increase the burden of measles.

“The waning of vaccine-induced immunity likely explains the observed dynamics and age distribution of vaccinated measles cases in England between 2010 and 2019,” the authors write. “Many near-elimination countries have reported decreased vaccine coverage since 2020, leading to an increase in measles incidence in Europe in 2023.”

Abstract/Full Text

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