Varicella-Zoster Virus (VZV): Understanding Chickenpox, Shingles, and Beyond
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Editorial note: This article is provided for educational purposes only. It is not medical advice. Always consult a qualified healthcare professional for diagnosis and treatment of any condition.
Emergency warning: Go to the nearest emergency room if you or your child has confusion or an altered mental state, a severe headache, a fever that does not go away, sores in the eyes, difficulty breathing, a stiff neck or trouble waking up.
Quick Answer
Varicella-zoster virus (VZV) is a herpes virus that causes chickenpox on first infection and shingles when it reactivates later. After chickenpox, it stays in nerve cells for life. Reactivation can cause a painful rash and, rarely, brain or eye infections and facial paralysis. There is no cure, but vaccination is the best way to prevent chickenpox and lower shingles risk. [1]
What the research says
The shingles vaccine cuts the risk of shingles by about 97% in adults 50 and older. In a trial of 15,411 adults aged 50 and older, two doses of an adjuvanted subunit shingles vaccine given two months apart reduced shingles by 97.2% (95% CI 93.7-99.0) compared with placebo over about 3.2 years. Strong injection-site and body reactions were more common with the vaccine (grade 3 symptoms in 17.0% vs 3.2%) (Lal et al., The New England Journal of Medicine, 2015 [2]).
Two doses of chickenpox vaccine protect much better than one. In 5,803 toddlers in Europe, two doses of a combined measles-mumps-rubella-varicella vaccine were 94.9% effective against any varicella and 99.5% against moderate or severe disease. One dose of varicella vaccine was 65.4% and 90.7% effective (Prymula et al., The Lancet, 2014 [3]).
Antivirals have not been shown to prevent long-term nerve pain. A Cochrane review of six trials (1,211 participants) of antivirals started within 72 hours of the shingles rash found no significant reduction in postherpetic neuralgia with oral aciclovir at four months (risk ratio 0.75; 95% CI 0.51-1.11). Four trials did suggest less pain four weeks after the rash began (Chen et al., Cochrane Database of Systematic Reviews, 2014 [4]).
Key takeaways
VZV is a herpes virus that causes chickenpox and, after staying dormant in nerve cells, can come back as shingles or other nerve-related illnesses [1].
Reactivation is more likely with age over 50, a weakened immune system, immunosuppressive medicines or high stress [1].
There is no cure, but vaccines lower the risk of chickenpox and shingles, and antivirals can help treat active infections [1] [2].
What is the varicella-zoster virus?
The varicella-zoster virus (VZV) belongs to the herpes virus family and causes several different illnesses. When a person is first exposed, it causes chickenpox (varicella), with a widespread itchy rash and fever. Unlike many viruses, VZV is not cleared completely: it retreats into nerve cells and stays there for life [1].
After recovery from chickenpox, the virus sleeps in the dorsal root ganglia of the spine, and sometimes in the trigeminal nerve of the face. It can stay inactive for years or decades and then reactivate, causing shingles (herpes zoster) or other, more serious nerve and eye problems [1].
What types of VZV infection are there?
A VZV infection looks different depending on whether it is a first infection or a reactivation [1]:
Chickenpox (varicella): the primary infection, with fluid-filled blisters and fever.
Shingles (herpes zoster): a reactivation that can happen decades later, causing nerve pain and a localized rash.
Meningitis, encephalitis and meningoencephalitis: in rare cases the virus reactivates and infects the brain or its lining.
Herpes zoster ophthalmicus: a reactivation around the eye and forehead that can threaten vision.
Ramsay-Hunt syndrome: a reactivation in the nerves of the face that can cause facial paralysis and ear pain.
Location of infection | Possible symptoms |
Skin and whole body | Fever, fluid-filled blisters, itchy rash, burning skin pain |
Head and face | Headache, facial paralysis, toothache, earache |
Eyes | Redness, swelling, light sensitivity (photophobia), sores |
Source: Cleveland Clinic [1].
How does VZV spread and reactivate?
During chickenpox, the virus spreads through coughing, sneezing and contact with the rash. During a shingles reactivation, it spreads through contact with the rash and sometimes through virus particles from the rash in the air. You cannot catch shingles from someone, but a person who has never had chickenpox or the vaccine can catch chickenpox from someone with shingles [1].
Reactivation usually happens when the immune system is lowered. It is more likely if you [1]:
are over 50,
take immunosuppressive medicines,
have an illness that weakens the immune system, such as HIV or cancer, or
are under a lot of stress.
How is VZV diagnosed and treated?
Providers usually diagnose VZV from your symptoms and the typical rash. If the diagnosis is unclear, they can send a sample of fluid or tissue from a blister to a lab to test for the virus [1].
No treatment removes the virus from the body. Antiviral medicines are sometimes used to treat active infections [1]. Trials of antivirals for shingles have tested treatment started within 72 hours of the rash appearing, and the evidence that they prevent long-term nerve pain is limited [4].
Medicine | Brand name example |
Acyclovir | Zovirax® |
Famciclovir | Famvir® |
Valacyclovir | Valtrex® |
Source: Cleveland Clinic [1].
How can VZV be prevented?
The best way to prevent a VZV infection is to be vaccinated against chickenpox. If you have already had chickenpox, a shingles vaccine can lower the chance that the virus reactivates [1]. Vaccines work well: two doses of chickenpox vaccine gave far better protection than one in a European trial [3], and a shingles vaccine cut shingles by 97.2% in adults aged 50 and older [2].
People with chickenpox should avoid contact with others until the rash is gone. Shingles rashes should be covered. It is especially important to avoid people with weakened immune systems and young children [1].
Bottom line: what every reader should remember
Varicella-zoster is a persistent virus that can affect health across a lifetime, from the itchy blisters of childhood chickenpox to the painful nerve problems of shingles in adults. Knowing the risks of reactivation and acting early can limit the harm. Thanks to vaccines, many people never have to experience a VZV infection [1].
Take action today: Contact a healthcare provider if you think you or your child has chickenpox or shingles. Ask your doctor about your vaccination status and how to lower your risk of shingles [1].
Frequently Asked Questions
1. Is varicella-zoster the same as chickenpox?
Varicella-zoster is the virus that causes chickenpox. Chickenpox is the illness that results from the first infection with the virus [1].
2. Can I get shingles from someone who has chickenpox?
No. You cannot get shingles from someone who has it. However, you can get chickenpox from someone with shingles if you have never had chickenpox or been vaccinated [1].
3. Does the varicella-zoster virus ever leave the body?
No. Once you are infected, the virus stays in your nerve cells for life, even after the symptoms of chickenpox or shingles have cleared [1].
4. What triggers VZV to reactivate as shingles?
Reactivation usually happens when the immune system is lowered, for example in people over 50, people taking immunosuppressive medicines, people with illnesses such as HIV or cancer, and people under a lot of stress [1].
5. Can shingles happen more than once?
Yes. Reactivations can occur more than once in a lifetime [1].
6. Where does the virus hide when it is inactive?
VZV is usually found in the dorsal root ganglia of the spine and can also be found in the trigeminal nerve of the face [1].
7. Is there a cure for VZV?
There is no cure that removes the virus from the body. Antiviral medicines can treat active infections, and vaccines can help prevent them or their reactivation [1].
8. How do doctors test for VZV?
Diagnosis is usually based on your symptoms and the rash. Providers can also send a sample of fluid or tissue from the rash to a lab [1].
9. Can the virus affect the eyes?
Yes. A reactivation around the eye and forehead, called herpes zoster ophthalmicus, can cause eye redness, swelling and sores [1].
10. What is Ramsay-Hunt syndrome?
Ramsay-Hunt syndrome is a VZV reactivation in the nerves of the face that can cause facial paralysis and ear pain [1].
11. How can I prevent spreading chickenpox?
If you have chickenpox, avoid contact with other people until you no longer have a rash. Shingles rashes should be covered. Avoid people with weakened immune systems and children, for example in schools or daycares [1].
12. Is the shingles vaccine necessary if I already had chickenpox?
Yes. If you have had chickenpox, a shingles vaccine can reduce the chance that the virus already in your body reactivates [1]. In a large trial of adults aged 50 and older, two doses of an adjuvanted shingles vaccine reduced the risk of shingles by 97.2% [2].
13. Can VZV cause brain infections?
Yes, in rare cases. Reactivation can infect the brain or its lining and cause meningitis, encephalitis or meningoencephalitis [1].
14. What are the first signs of a VZV infection?
Symptoms depend on where the virus infects you and can include fever, headache, burning pain in the skin and a rash with fluid-filled blisters [1].
15. Is varicella-zoster related to the herpes simplex virus?
Yes. VZV is in the same family of viruses as herpes simplex [1].
Related Reading
Shingles Vaccine (Shingrix): Who Needs It, Doses and Side Effects explains who should get the shingles vaccine and how well it works.
References
Cleveland Clinic. Varicella Zoster Virus (VZV): Infection & Diseases. Cleveland Clinic. Last updated April 2, 2024. https://my.clevelandclinic.org/health/diseases/varicella-zoster-virus
Lal H, Cunningham AL, Godeaux O, et al. Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults. The New England Journal of Medicine. 2015;372(22):2087-2096. PMID: 25916341. https://doi.org/10.1056/NEJMoa1501184
Prymula R, Bergsaker MR, Esposito S, et al. Protection against varicella with two doses of combined measles-mumps-rubella-varicella vaccine versus one dose of monovalent varicella vaccine: a multicentre, observer-blind, randomised, controlled trial. The Lancet. 2014;383(9925):1313-1324. PMID: 24485548. https://doi.org/10.1016/S0140-6736(12)61461-5
Chen N, Li Q, Yang J, et al. Antiviral treatment for preventing postherpetic neuralgia. Cochrane Database of Systematic Reviews. 2014;(2):CD006866. PMID: 24500927. https://doi.org/10.1002/14651858.CD006866.pub3
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