What causes shingles?
After you have chickenpox, the varicella-zoster virus stays dormant in nerve ganglia near the spinal cord or brain. When cell-mediated immunity weakens—with age, chemotherapy, immunosuppressive drugs or major stress—the virus can reactivate and travel along a nerve to the skin. That's why the rash typically shows up as a band on one side of the body, following the area a single nerve supplies.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
What are the symptoms and complications?
- Early warning: tingling, burning pain or itching for a few days before the rash
- Rash: clusters of blisters on red skin that crust over in 7–10 days
- Postherpetic neuralgia: nerve pain lasting months after the rash heals, more common with age
- Eye involvement: a rash on the forehead or tip of the nose can threaten the eye and needs an eye doctor
How is shingles treated?
Starting an antiviral such as acyclovir, valacyclovir or famciclovir within 72 hours of the rash can speed healing and shorten pain. Pain control is a key part of treatment. While blisters are open, the virus can spread to people who've never had chickenpox and give them chickenpox.
How well do shingles vaccines work?
| Vaccine / trial | Population | Efficacy against shingles |
|---|---|---|
| Live attenuated (Oxman et al., 2005) | 38,546 adults 60+ | 51.3% (66.5% against postherpetic neuralgia) |
| Recombinant, ZOE-50 (Lal et al., 2015) | Adults 50+ | 97.2% |
| Recombinant, ZOE-70 (Cunningham et al., 2016) | Adults 70+ | 89.8% |
The recombinant vaccine often causes sore arms and fatigue that fade within a few days. The live vaccine can't be given to people with severely weakened immune systems. To read efficacy numbers as real-world risk, see relative vs. absolute risk.
FAQ
- Is shingles contagious?
- You can't catch shingles from someone, but fluid from the blisters can give chickenpox to people who've never had it or been vaccinated.
- Can you get shingles more than once?
- Yes, it can recur, which is one reason vaccination is recommended even after an episode.
Sources reviewed: 2026-10-25
References
- Oxman, M. N., Levin, M. J., Johnson, G. R., et al. (2005). A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. New England Journal of Medicine, 352(22), 2271–2284.
- Lal, H., Cunningham, A. L., Godeaux, O., et al. (2015). Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults. New England Journal of Medicine, 372(22), 2087–2096.
- Cunningham, A. L., Lal, H., Kovac, M., et al. (2016). Efficacy of the herpes zoster subunit vaccine in adults 70 years of age or older. New England Journal of Medicine, 375(11), 1019–1032.