SACRAMENTO, Calif. — A new study is showing the importance of getting a live shingles vaccine. The live zoster vaccine, designed to prevent shingles, is most effective in the first year after vaccination, but it still offers substantial protection against shingles and its complications even 10 years after inoculation, including in individuals with weakened immune systems.
Vaccine effectiveness is a measure of how well vaccines perform in real-world conditions, safeguarding communities against diseases.
Shingles, scientifically known as herpes zoster, is a painful skin rash triggered by the reactivation of the chickenpox virus. It is more common among people 60 and older and those with weakened immune systems, often leading to severe complications.
The live zoster vaccine was the first shingles vaccine, administered to over 50 million people worldwide. While it is no longer recommended for individuals with weakened immune systems and is not used in the United States, it is still administered in other countries, including the United Kingdom and Australia. However, the long-term effectiveness of the vaccine using real-world data has been uncertain.
To address this gap in knowledge, researchers utilized data from a large healthcare provider in the United States, Kaiser Permanente Northern California, to assess the vaccine’s long-term effectiveness against herpes zoster infection, hospital admissions due to herpes zoster, postherpetic neuralgia (persistent pain in the rash area), and herpes zoster ophthalmicus (rash in or around the eye).
According to a media release, the study involved data from more than 1.5 million adults 50 and older eligible for the live zoster vaccine. Among them, 507,444 individuals (34%) received the vaccine between Jan. 1, 2007, and Dec. 31, 2018.
Among the 75,135 cases of herpes zoster, 4,982 (7%) developed postherpetic neuralgia, 4,439 (6%) had herpes zoster ophthalmicus, and 556 (0.7%) were admitted to the hospital for herpes zoster.
The study found that vaccine effectiveness was highest in the first year after vaccination and declined progressively over time.
In the first year, the vaccine was 67 percent effective against herpes zoster infection, 83 percent effective against postherpetic neuralgia, 71 percent effective against herpes zoster ophthalmicus, and 90 percent effective against hospital admissions due to herpes zoster.
Effectiveness against herpes zoster decreased to 50 percent in the second year, then dropped to 27 percent in the eighth year, and finally settled at 15 percent after a decade. A similar trend was observed for herpes zoster ophthalmicus.
For postherpetic neuralgia and hospital admissions, the vaccine’s effectiveness started higher and declined over time but still provided substantial protection for several years (41% after 10 years for postherpetic neuralgia and 53% between 5 and 8 years for hospital admissions).
The study found that vaccine effectiveness was generally consistent across different groups defined by age, gender, race or ethnicity, and immunocompromise status at vaccination.
While these findings are observational and come with certain limitations, they align with results from randomized trials and other observational studies. The research contributes valuable information about the real-world duration of vaccine protection and can guide improvements to shingles vaccination programs, including the timing of follow-up or booster doses.
The study also reinforces the notion that the live zoster vaccine is effective against herpes zoster in immunocompromised adults. Researchers suggest that further research should investigate vaccine effectiveness over time in individuals with chronic diseases, such as those affecting the kidney, heart, and autoimmune systems.
The study is published in the journal The BMJ.
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