Effectiveness of the live zoster vaccine during the 10 years following vaccination: real world cohort study using electronic health records
Study in over 1.5 million people age≥ 50 years in US (507 444 vaccinated) followed for almost 9.4-million-person years found live zoster vaccine was effective initially but effectiveness waned substantially, though some protection remained 10 years after vaccination.
Source:
British Medical Journal
SPS commentary:
Across all follow-up time, overall vaccine effectiveness was 46% (45% to 47%) against herpes zoster, 62% (59% to 65%) against postherpetic neuralgia, 45% (40% to 49%) against herpes zoster ophthalmicus, and 66% (55% to 74%) against admission to hospital for herpes zoster.
According to an editorial, this work is timely because herpes zoster vaccination programmes, such as the one introduced in UK in 2017 are expanding to include people who are younger, older, and at risk from immunocompromised. It notes this new research is an excellent example of a real-world observational study, using high quality health data, relevant epidemiological designs, and methods to control for biases. It adds that the capability to determine precise estimates of waning effectiveness over time, provides new and valuable information on need for and timing of follow-up or booster doses. It points to evidence suggesting that high vaccine effectiveness can be reached with a subsequent dose of herpes zoster vaccine, so booster or second doses for people in the older groups could be considered. It calls for more research to evaluate the trajectory of vaccine effectiveness against herpes zoster and severe outcomes over time in people with chronic diseases.