As of 2021 it remained to be confirmed whether a booster dose was required, but the Advisory Committee on Immunization Practices (ACIP) in the United States recommends Shingrix for adults over the age of 50, including those who have already received Zostavax. Shingrix
The ACIP voted that Shingrix is preferred over Zostavax for the prevention of zoster and related complications because data showed vaccine efficacy of more than 90% against shingles across all age groups. Unlike Zostavax, which is given as a single shot, Shingrix is given as two intramuscular doses, two to six months apart. Most of the studies conducted showed efficacy to at least 4 years post-vaccination, but it is possible the vaccine may provide protection for much longer.A large randomized clinical trial showed Shingrix reduced the incidence of shingles 96.6% in the 50–59 age group, and 91.3% in those over age 70. The absolute decrease in risk of herpes zoster following immunization over three and a half years is 3.3% (3.54% down to 0.28%) while the decrease in the risk of postherpetic neuralgia is 0.3% (0.34% down to 0.06%). Zostavax
A Cochrane review concluded that Zostavax is "effective in preventing herpes zoster disease for up to three years". The duration of protection beyond four years after vaccination with the zoster vaccine is unknown. The need for re-vaccination remains to be confirmed.Zostavax was shown to reduce the incidence of shingles by 51% in a study of 38,000 adults aged 60 and older who received the vaccine.
Vaccine already held by practitioners could still be administered up to the expiration date (none expired later than November 2020).The U.S. Centers for Disease Control and Prevention (CDC) recommends that healthy adults 50 years and older get two doses of Shingrix, at least two months apart. Initial clinical trials only tested a gap of less than six months between doses, but unexpected popularity and resulting shortages caused further testing to validate wider spacing of the two doses. Shingrix, which provides strong protection against shingles and PHN, was preferred over Zostavax before Zostavax was discontinued.The zoster vaccine is covered by Medicare Part D. In 2019, more than 90% of Medicare Part D vaccine spending was for the zoster vaccine. 5.8 million vaccine doses were administered to Part D beneficiaries that year at a cost of $857 million. References
Further reading
World Health Organization (2014). "Varicella and herpes zoster vaccines : WHO position paper, June 2014" (PDF). Weekly Epidemiological Record. 89 (25): 265–287. hdl:10665/242227. PMID 24983077. Hamborsky J, Kroger A, Wolfe S, eds. (2015). "Chapter 22: Varicella". Epidemiology and Prevention of Vaccine-Preventable Diseases (13th ed.). Washington D.C.: U.S. Centers for Disease Control and Prevention (CDC). ISBN 978-0990449119. External links
Zostavax Product Page U.S. Food and Drug Administration (FDA)
Shingrix Product Page U.S. Food and Drug Administration (FDA)
"Shingrix Vaccine Information Statement". U.S. Centers for Disease Control and Prevention (CDC). 29 July 2021. "Zostavax (Herpes Zoster Vaccine) Questions and Answers". Questions about Vaccines. U.S. Food and Drug Administration (FDA). 18 February 2021.