Shingles and Post Herpetic Neuralgia Vaccine

July 5, 2016

What is the best method of shingles and post herpetic neuralgia treatment? A vaccine in phase 3 trials may be the answer.

Shingles and post herpetic neuralgia are painful conditions. Generally, the onset of shingles is unprovoked, although people who are older, or who have immune deficiency are more prone to the disease. Shingles and post herpetic neuralgia result from the reactivation of latent herpes zoster virus in an individual who has already had a previous infection with chicken pox virus, often decades prior to the reactivation of the virus, which stays dormant in the ganglia for years. Shingles is a painful condition caused by reactivation of the virus. Some people who get shingles go on to develop a persistent pain syndrome, post herpetic neuralgia, which can last as long as 3-9 months. 

Treatment of shingles and post herpetic neuralgia 

Treatment for shingles and post herpetic neuralgia is focused on minimizing pain. There have not been any breakthrough developments in the management of the symptoms for many years. Oral prescriptions for neuropathic pain are often only moderately effective. Increasing the doses of anticonvulsants and other oral treatments for neuropathic pain to attain a more potent effect is typically intolerable due to side effects such as dizziness, fatigue, and sleepiness. Topical treatments can be used as adjunctive therapy to provide additional pain relief along with oral remedies. But topical therapy alone is almost never enough to control the pain. 

Vaccination for shingles and post herpetic neuralgia

Another interesting approach to the management of shingles and post herpetic neuralgia is vaccination. Vaccination against the reactivation of herpes zoster virus seems counterintuitive because of the fact that people who are at risk for shingles already have the varicella zoster virus in their bodies and already mounted a natural immune response, usually during childhood, protecting them from another bout of chicken pox. The relatively newly developed vaccine, however, activates T cell production, preventing reactivation of the virus. Vaccines that include live attenuated herpes zoster virus show efficacy results ranging between 49-65% on measures such as severity, duration, and recurrence of shingles and post herpetic neuralgia. The protective effects of the vaccine weaken over time, with a marked decline around 5-7 years after vaccination. This raises the question of whether re-vaccination is useful for adults who have had shingles or post herpetic neuralgia or who have a known risk of viral reactivation.

A newer vaccine is comprised of a herpes zoster glycoprotein subunit with a T cell boosting adjuvant. This HZ/su vaccine, Shingrix, currently in phase III trials, has preliminarily been reported to have 97% effectiveness in study participants who are immunocompetent. So far, the HZ/su vaccine has been reported as safe for immunocompromised patients in the trial phase. 

What are your criteria for shingles vaccine for your patients? Have you recommended herpes zoster vaccine for patients who have already had one episode of shingles or post herpetic neuralgia or do you recommend the vaccine for patients who are at risk, even if they have not had evidence of reactivation? Given the recent controversies about childhood vaccination, have any of your adult patients asked about vaccines for any adult onset illnesses?

References:

Cunningham AL. The herpes zoster subunit vaccine Expert Opinion in Biological The herpes zoster subunit vaccine. Expert Opin Biol Ther. 2016 Feb;16(2):265-271.

Hadley GR, et al. Post-herpetic neuralgia: a review. Curr Pain Headache Rep. 2016 Mar;20(3):17.

Kim KH. Herpes zoster vaccination. Korean J Pain. 2013 Jul;26(3):242-248.