A shingles simulation
A simulation of shingles and lasting nerve pain, with and without the Shingrix vaccine.
What happens to 1,000 unvaccinated adults in the years after 50?
- Shingles
- 0
- Lasting nerve pain
- 0
A painful, blistering rash that clears in about 2 to 4 weeks.
Postherpetic neuralgia: burning pain that can last months or years.
How it works
The simulation follows 1,000 adults through life after 50, showing how many get shingles and how many have lasting nerve pain. It then re-rolls the dice as if all had been vaccinated.
This is a Monte Carlo simulation: for each adult, we roll dice weighted by likelihood.
Getting shingles. An unvaccinated adult faces about a 33% lifetime risk, roughly one in three, per the CDC. The virus is the same one that causes chickenpox, reactivating decades later.
Nerve pain. About 15% of shingles cases progress to postherpetic neuralgia, nerve pain that can last months or years after the rash clears. It’s the complication most worth avoiding.
Two doses of Shingrix are about 90% effective at preventing shingles, blending the ZOE-50 and ZOE-70 trials, and they prevent the nerve pain along with the cases they stop.
Caveats. The model holds that 90% flat across the whole horizon, but protection is only proven to about ten years; how much longer it lasts isn’t known.
Sources
- Lal et al. (ZOE-50), Efficacy of an Adjuvanted Herpes Zoster Subunit Vaccine in Older Adults (NEJM 2015)
Randomized placebo-controlled trial in adults 50+: Shingrix (recombinant zoster vaccine) efficacy against shingles of 97.2% (95% CI 93.7-99.0).
- Cunningham et al. (ZOE-70), Efficacy of the Herpes Zoster Subunit Vaccine in Adults 70 Years or Older (NEJM 2016)
In adults 70+, vaccine efficacy against shingles was 89.8% (95% CI 84.2-93.7) and efficacy against postherpetic neuralgia was 88.8%. Pooled efficacy against PHN in adults 50+ was 91.2%. Protection held with advancing age, unlike the older live vaccine.
- Dooling et al., Recommendations of the ACIP for Use of Herpes Zoster Vaccines (MMWR 2018)
ACIP recommends two doses of Shingrix for immunocompetent adults 50+, including those who previously received the live Zostavax vaccine. Recombinant zoster vaccine is preferred over Zostavax.
- CDC: Clinical Considerations for Use of Recombinant Zoster Vaccine (Shingrix)
Shingrix is two doses given 2 to 6 months apart (1 to 2 months for people who are or will be immunocompromised). If more than 6 months pass, give dose 2 without restarting the series. The live Zostavax vaccine was discontinued in the US on November 18, 2020.