Kaiser Permanente vaccine researchers report long-term study of Zostavax, no longer used in U.S.
The original vaccine against shingles — Zostavax, a live shingles vaccine no longer used in the U.S. — is effective in the first year after vaccination but wanes significantly over the following decade, according to a study by Kaiser Permanente’s Vaccine Study Center published in the journal BMJ.
The new analysis is the largest long-term look at effectiveness of Zostavax, examining how well it protected against herpes zoster (shingles) infection as well as 3 complications associated with shingles: persistent pain, eye involvement, and hospitalization. The study included 1.5 million patients of Kaiser Permanente Northern California aged 50 and older who were eligible for the shingles vaccine between 2007 and 2018; 34% of those eligible received the vaccine.
The study found strongest effectiveness against shingles in the first year (67%), which dropped to 50% the second year, 27% the eighth year, and 15% after 10 years.
“This study confirms what we knew about the live herpes zoster vaccine, that its effectiveness against shingles waned during the 8 years of our earlier study,” said lead author Nicola Klein, MD, PhD, a research scientist with the Kaiser Permanente Division of Research and director of its Vaccine Study Center. “We now also add insights about how much protection remains after 10 years, and how well the vaccine protected people of varying ages against other outcomes, such as persistent pain, eye involvement and hospitalization.”
The 10-year analysis found that the live shingles vaccine provided continued protection against side effects. For postherpetic neuralgia — pain related to the outbreak site — effectiveness was 83% in the first year, waning to 41% at 10 years. Effectiveness rates were similar for hospitalization. For herpes zoster ophthalmicus — eye involvement — the vaccine had 71% effectiveness the first year, waning to 12% at 10 years.
Also significant, Klein said, was that effectiveness was similar across age groups, from ages 50 through age 80 and older, particularly for pain and hospitalization. Previous research had suggested that the oldest patients might not benefit as much from the live shingles vaccine, she said.
The study tallied 75,135 herpes zoster cases; 7% developed postherpetic neuralgia (pain), 6% herpes zoster ophthalmicus, and 0.7% were hospitalized for herpes zoster.
The live vaccine, Zostavax, was replaced in the U.S. by Shingrix, a recombinant vaccine with greater effectiveness that the Food and Drug Administration approved in 2017. Zostavax is still used in some countries. U.S. patients who received the original live vaccine have been recommended to get the newer recombinant vaccine, which is given as a two-shot series.
Shingles is a painful rash caused by reactivation of the chickenpox virus. Older people and those with weakened immune systems are at greater risk. The Centers for Disease Control and Prevention recommends all adults aged 50 and older, and people 19 or older who have weakened immune systems, be vaccinated with the current recombinant zoster vaccine.
Zostavax has been given to more than 50 million people worldwide. It was introduced in the U.S. in 2006 and discontinued in 2020.
The study’s authors also noted their analysis used novel analytical methods that could be useful for other real-world studies examining the duration of the protection conferred by a vaccine.
The study and its associated clinical trials were funded by Merck Sharp and Dohme LLC.
Co-authors were Joan Bartlett, MPH, MPP, Bruce Fireman, John Hansen, MPH, Edwin Lewis, MPH, and Laurie Aukes, RN, of the Vaccine Study Center; and Morgan A. Marks, PhD, ScM, and Patricia Saddier, MD, PhD, of Merck.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and society at large. It seeks to understand the determinants of illness and well-being, and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 450 epidemiological and health services research projects. For more information, visit divisionofresearch.kaiserpermanente.org or follow us @KPDOR.