How effective is vaccination against post herpetic neuralgia ? (pain after shingles (herpes zoster))

• Shingles is due to the activation of the herpes zostervirus (HZV) following its reactivation from doral ganglia following chicken pox.
• It is usually self-limited but after 60 there is a much higher incidence of pain following shingles (post-herpetic neuralgia). The pain can last from months to years afterwards.

• Incidence of shingles and post herpetic neuralgia was sought.

• The authors collected data from patients from 2007 to 2009, from a patient database using diagnostic and therapeutical codes:
  • Shingles was considered if there was no evidence of shingles in the year preceeding the vaccine
  • Post-herpetic neuralgia was diagnosed for those who developed pain more than 90 days after shingles

• 766330 people were included in the study. The median age was 75 years of age and 29785 received the vaccine (less than 4% of the study population (3.8%))
• Out of the whole group, 13100 developed zoster (incidence over the 3 year period of around 2% (1.7 %))

Key results with the vaccine

• The incidence of herpes zoster was reduced by 48%
• The incidence of herpes zoster in immunosuppressed individuals was reduced by 37%
• The incidence of post-herpetic neuralgia was reduced by 59%.

Comment: limitations include an imprecise diagnosis as the the collection is through diagnosis codes and thus indirect.

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

Source of Information: Langan S. et al. Herpes zoster vaccine effectiveness against incident herpes zoster and post-herpetic neuralgia in an older US population. International Investigative Dermatology (IID) 2013 – Edinburgh, United Kingdom (UK)