Vaccine effectiveness highest in first year after vaccination and decreases considerably over time
By Elana Gotkine HealthDay Reporter
MONDAY, Dec. 11, 2023 (HealthDay News) — Live zoster vaccination is initially effective against outcomes, including herpes zoster and admission for herpes zoster, but the effectiveness wanes over time, according to a study published online Nov. 8 in The BMJ.
Nicola P. Klein, M.D., PhD., from the Kaiser Permanente Study Center in Oakland, California, and colleagues examined the effectiveness of the live zoster vaccine during more than 10 years after vaccination in a real-world cohort study involving more than 1.5 million people aged 50 years and older followed for almost 9.4 million person-years.
Overall, 34 percent of the 1,505,647 people were vaccinated with live zoster vaccine. The researchers found that among 75,135 incident herpes zoster cases, 7 and 6 percent developed postherpetic neuralgia and had herpes zoster ophthalmicus, respectively, and 0.7 percent were admitted to the hospital for herpes zoster. Vaccine effectiveness was highest in the first year after vaccination for each outcome and decreased considerably over time. Vaccine effectiveness against herpes zoster waned from 67 percent in the first year to 15 percent after 10 years. Effectiveness against postherpetic neuralgia, herpes zoster ophthalmicus, and admission for herpes zoster waned from 83 to 41 percent, 71 to 29 percent, and 90 to 53 percent, respectively, during five to less than eight years. Overall vaccine effectiveness across all follow-up time was 46, 62, 45, and 66 percent against herpes zoster, postherpetic neuralgia, herpes zoster ophthalmicus, and admission for herpes zoster, respectively.
“We found that live zoster vaccine conferred much protection initially but protection waned substantially over time,” the authors write.
Several authors disclosed ties to pharmaceutical companies, including Merck, the manufacturer of the vaccine and sponsor of the study.
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