Shingles, also known as herpes zoster, is a viral infection causing a painful rash with blisters. This condition arises from the reactivation of the varicella-zoster virus, the same virus responsible for chickenpox, which can lie dormant in the body for decades. The risk of developing shingles and its complications, like long-lasting nerve pain called postherpetic neuralgia (PHN), increases significantly with age. Vaccination reduces the likelihood of experiencing shingles and its associated discomfort.
Duration of Vaccine Protection
The duration of protection from a shingles vaccine varies depending on the specific vaccine administered. Shingrix is the primary vaccine used, having largely replaced an older vaccine called Zostavax. Shingrix is recommended for adults aged 50 and older, as well as for immunocompromised individuals aged 19 and older. This vaccine is administered as a two-dose series, typically given between two and six months apart. For those with weakened immune systems, the second dose can be given sooner, within one to two months, to accelerate protection.
Shingrix demonstrates high effectiveness in preventing shingles. Clinical trials show it is approximately 97% effective for adults aged 50 to 69 and about 91% effective for those aged 70 and older. Long-term follow-up data from the ZOSTER-049 trial, tracking participants for up to 11 years, reveals sustained efficacy. This research shows the vaccine maintains 79.7% effectiveness against shingles in adults aged 50 and over and 73.1% in those aged 70 and over, even after a decade, indicating protection can extend for a decade or more.
Zostavax, an older live-attenuated vaccine, was discontinued in the United States in November 2020. Unlike Shingrix, Zostavax was given as a single dose. It reduced the risk of shingles by 51% in adults aged 60 and older. However, its protection diminished considerably over time, dropping from 67% in the first year to 50% in the second, and further declining to 15% after 10 years. Its protection lasted for about three to five years.
Maintaining Long-Term Immunity
While Shingrix provides significant and durable protection, immunity can gradually lessen over time. Current data indicates this decline is slow, with high levels of protection persisting for many years. Public health guidelines currently do not recommend booster doses of Shingrix after the initial two-dose series. This recommendation is based on the robust and sustained efficacy observed in long-term studies.
As researchers continue to gather more long-term data on Shingrix, recommendations regarding future booster doses could evolve. Completing the two-dose regimen is important, as it provides the most comprehensive and sustained protection. Even if there is a delay in receiving the second dose beyond the recommended six-month window, it is still advised to get it as soon as possible rather than restarting the series. For individuals who previously received Zostavax, current recommendations advise getting the Shingrix vaccine to ensure more effective and longer-lasting protection.