THE RISK of developing shingles (herpes zoster virus), a skin condition that occurs once the varicella-zoster virus is reactivated in nerve cells, can be significantly reduced in older adults through the use of vaccination, according to the results of a retrospective cohort study.
Researchers considered the effectiveness and durability of ZOSTAVAX®, which is the vaccine that has been available since 2006, although it is currently underutilised. The data of around 2 million Medicare beneficiaries from 2007–2014 was evaluated. Results revealed that the vaccine was most efficacious against severe cases of shingles and postherpetic neuralgia, a serious complication that occurs with the virus that can cause chronic pain.
The vaccine displayed 74% effectiveness for reducing the cases of hospitalisation in shingles patients within the first 3 years of receiving the vaccine and 55% effectiveness after ≥4 years. In preventing cases of postherpetic neuralgia, the vaccine demonstrated an effectiveness of 57% within the first 3 years of vaccination and 45% in the following years. The vaccination’s protection against less severe cases of shingles was discovered to be much weaker. Finally, little evidence was found suggesting that protection from shingles varied among different age groups.
Study author Dr Hector Izurieta, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration (FDA), Silver Spring, Maryland, USA, explained that: “The fact that we found relatively high effectiveness against serious outcomes, such as hospitalisation and postherpetic neuralgia, and that protection from these outcomes was sustained over time, adds to the considerable evidence that the vaccine is beneficial and that seniors should be encouraged to be vaccinated in higher numbers than what is happening currently.” Indeed, only 28% of American adults aged ≥60 had the vaccine in 2014.
Speaking about how to continue research in this direction in the future, Dr Izurieta suggested: “Better methods should be developed to control for bias in the analysis of observational studies, particularly when less severe outcomes, such as community herpes zoster, are considered.”