Zostavax Vaccine Efficacy: A 12-Year Review

The researchers conducted the study because protection against herpes zoster has been "shown to wane with time" and effect sizes "can be imprecise".

This article is written live from ID Week 2017 Annual Meeting in San Diego, CA. MPR will be reporting news on the latest findings from leading experts in infectious diseases. Check back for more news from IDWeek 2017.

SAN DIEGO—At IDWeek 2017, experts from the Centers for Disease Control and Prevention (CDC) and Marshfield Clinic Research Institute presented findings from a systematic review of the duration of efficacy of Zostavax (zoster vaccine live [ZVL]; Merck) against herpes zoster infection.

Zostavax was approved in 2006 for the prevention of herpes zoster (shingles) in adults ≥60 years of age. Because protection against herpes zoster has “shown to wane with time” and effect sizes “can be imprecise,” study authors, led by Kathleen Dooling, MD, MPH, conducted a systematic review of the duration of efficacy and effectiveness of ZVL against herpes zoster.

The team searched various databases, including PubMed, EMBASE, Cochrane, and clinicaltrials.gov for studies evaluating vaccine efficacy or effectiveness of ZVL among immunocompetent patients aged ≥60 years. Of the 1,302 total articles analyzed, 8 were included for the review (5 observational studies, 2 quasi-experimental studies, and 1 Phase 3 randomized controlled trial).  

Vaccine efficacy rates from baseline to 4 years post-vaccination varied from 33% to 55% in 1 experimental and 5 observational studies analyzed, and 19% to 40% in 2 quasi-experimental and 3 observational studies. 

“Most experimental and observational studies estimate vaccine efficacy for adults 60 years and older to be just above 50% during the 3 years following receipt of ZVL,” the researchers reported. “Beyond 3 years, ZVL protection wanes, with all studies estimating VE ≤40% after 4 years.”

Older age at the time of vaccination and longer time since vaccination were both associated with lower protection from ZVL, they noted.

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Dooling, K. Performance of Zoster Vaccine Live (Zostavax): A Systematic Review of 12 years of Experimental and Observational Evidence. Poster presented at IDWeek; October 4–8, 2017; San Diego, CA. http://www.idweek.org