The CDC recommends a single dose of the live attenuated herpes zoster vaccine for Americans aged 60 years and older, despite history of chickenpox or shingles. A new study questions, however, whether one is enough.
The report in the American Journal of Preventive Medicine points to research suggesting that the vaccine’s effect wanes over time. “Because vaccine-induced protection decreases to zero after 10 years, many vaccinated people will soon be subject to an increased risk of the disease,” explained researchers from the Cleveland Clinic’s Center for Value-Based Care Research.
The study team created a Markov model to follow vaccinated individuals for a lifetime, comparing, from a societal perspective, no booster with booster options in terms of costs and quality-adjusted life years. Factors included when the booster was provided—any time between 1 and 20 years after the first dose—and at what age it was initially received—60, 70, or 80.
Neither costs nor side effects of the first dose were included in the model, developed in 2016, because participants already had been vaccinated. One assumption was that the booster would have the same efficacy and waning rate as the initial vaccination.
The threshold of cost effectiveness was set at $100,000 per quality-adjusted life year, and whether the booster met that threshold varied by age and time since vaccination, according to the researchers. Based on study results, the booster cost less than $100,000/quality-adjusted life year if given more than 5 years after the initial dose but was most cost-effective at about the 10-year mark.“Under current assumptions, a booster dose of herpes zoster vaccine would be cost-effective for all vaccinated people 10 years after initial vaccination,” the researchers conclude.