Zostavax was discontinued because a newer, more effective shingles vaccine replaced it. Merck stopped selling Zostavax in the United States on November 18, 2020, after the CDC shifted its recommendation to Shingrix, which provided significantly stronger and longer-lasting protection. The decision came down to two core problems with Zostavax: its protection faded quickly, and as a live vaccine, it couldn’t be given to people with weakened immune systems, the very group most vulnerable to shingles.
How Zostavax’s Protection Faded
Zostavax worked reasonably well in its first year, cutting the risk of shingles by about 67%. But that number dropped fast. By year two, effectiveness fell to roughly 50%. After a decade, it offered only about 15% protection against shingles. The CDC itself noted that protection lasted about five years, which created a practical problem: adults vaccinated in their 50s or early 60s often lost their protection by the time their risk of shingles was highest.
The decline was less dramatic for the most serious complication of shingles, a condition called postherpetic neuralgia, where nerve pain lingers for months or even years after the rash clears. Protection against that started at 83% in year one and dropped to around 41% after a decade. Similarly, protection against shingles affecting the eye started at 71% and fell to 29% within five to eight years. Protection against hospitalization dropped from 90% to 53% over that same window. A vaccine that loses most of its punch within a few years is a hard sell when a better alternative exists.
The Live Vaccine Problem
Zostavax contained a live, weakened form of the varicella-zoster virus, the same virus that causes chickenpox and shingles. For most healthy adults, this was fine. But live vaccines are contraindicated for most people with compromised immune systems, including those on immunosuppressive medications, people undergoing chemotherapy, organ transplant recipients, and people living with HIV who have very low immune cell counts. These patients face some of the highest risks for shingles reactivation, yet Zostavax couldn’t safely be given to them.
Shingrix solved this problem entirely. It’s a recombinant vaccine, meaning it uses a single protein from the virus rather than a live virus. That makes it safe for immunocompromised patients, expanding protection to the people who need it most.
Shingrix Outperformed It Dramatically
Zostavax’s overall efficacy against shingles was 51%, with 67% protection against postherpetic neuralgia. Shingrix, by comparison, was estimated to be roughly 84% more effective than Zostavax against shingles in indirect comparisons. Clinical trials showed Shingrix preventing more than 90% of shingles cases in adults over 50, and its protection held up far better over time. It requires two doses given two months apart rather than a single shot, but the trade-off in durability and potency made that an easy choice for public health officials.
The gap was especially stark in older adults. Zostavax’s efficacy dropped noticeably in people over 70, the age group where shingles is most common and most dangerous. Shingrix maintained high efficacy even in this older population, which was a major factor in the CDC’s 2017 decision to recommend it as the preferred shingles vaccine.
The Timeline of Withdrawal
The shift happened in stages. In October 2017, the CDC’s Advisory Committee on Immunization Practices recommended Shingrix as the preferred vaccine for adults 50 and older, including those who had previously received Zostavax. Zostavax remained available for a few years as supplies of Shingrix were limited (there were notable shortages in 2018 and 2019). But by November 2020, Merck officially pulled Zostavax from the U.S. market.
Internationally, the timeline was slower. Zostavax continued to be available in some countries for several more years. The European Medicines Agency withdrew its marketing authorization on June 1, 2025, after Merck requested the withdrawal and confirmed it would permanently discontinue the product for commercial reasons. The vaccine had already stopped being marketed in the EU as of May 2025.
If You Previously Got Zostavax
Having received Zostavax in the past doesn’t mean you’re still protected, and it doesn’t prevent you from getting Shingrix. The CDC recommends that anyone who previously received Zostavax should get the two-dose Shingrix series. You need to wait at least eight weeks after your Zostavax dose before starting Shingrix.
Some guidelines initially suggested waiting five years between the two vaccines, since that was the interval studied in clinical trials. However, the CDC has clarified that shorter intervals are acceptable because there are no safety or effectiveness concerns with getting Shingrix sooner. Your doctor may recommend an earlier timeline depending on how old you were when you received Zostavax and how much time has passed since then. Given that Zostavax’s protection drops significantly after just a few years, waiting isn’t necessarily doing you any favors.