Shingles is a painful condition caused by the varicella-zoster virus, the same virus that causes chickenpox. If you had chickenpox as a child, that virus never fully left your body. It settled quietly in your nerve cells and can wake up years, even decades, later as shingles. Here we explain why the virus reactivates, who is most at risk, what complications such as postherpetic neuralgia involve, and how the NHS shingles vaccine works.
What is shingles?
Shingles is caused by the varicella-zoster virus. After you recover from chickenpox, the virus does not disappear. It stays dormant in your body and can reactivate later to cause shingles if your immune system is weakened (NHS, Shingles).
The main symptom is a painful rash, usually on the chest and tummy, though it can appear anywhere including the face, eyes and genitals. It almost always shows up on one side of the body only. The rash can take up to four weeks to heal. You cannot give shingles to other people, but someone could catch chickenpox from you if they have not had it before (NHS, Shingles).
Why does the chickenpox virus reactivate years later?
This is the question most people ask, and the answer comes down to where the virus hides and how your immune system changes over time.
Following a primary chickenpox infection, the virus travels along your sensory nerves to the sensory dorsal root ganglia, clusters of nerve cells near the spinal cord, and establishes a permanent latent infection there. Reactivation can occur decades later and causes shingles, with the risk and severity increasing as you get older (UKHSA, Green Book chapter 28a).
Age-related decline in immunity
While the virus lies dormant in the nerve cells, your immune system normally keeps it in check. Reactivation is thought to be associated with a decline in cell-mediated immunity, linked to immune senescence (the natural ageing of the immune system) or to suppression of the immune system (UKHSA, Shingles immunisation programme for healthcare practitioners).
The virus can also reactivate when your immune system is particularly vulnerable for other reasons, for instance after flu, or during periods of stress or trauma. Anyone who has had chickenpox is at risk of shingles later in life (UKHSA blog, symptoms of shingles and the connection to chickenpox).
Who is most at risk of shingles?
Because reactivation is tied to weaker immunity, two groups face the highest risk:
- Older adults. The risk and severity of shingles rise with age as cell-mediated immunity declines (UKHSA, Green Book chapter 28a).
- People with a weakened immune system. Immunosuppression, whether from a health condition or its treatment, makes reactivation more likely (UKHSA, Shingles immunisation programme for healthcare practitioners).
To put the lifetime risk in context, around 1 in 5 people will go on to develop shingles at some point in their lives (NHS England).
Complications: postherpetic neuralgia and more
For many people shingles clears up within a few weeks, but it can lead to complications. These include postherpetic neuralgia (long-lasting pain), bacterial infection, scarring, muscle weakness, and eye problems that can lead to sight loss (NHS, Shingles).
Postherpetic neuralgia is the most common complication. It is long-lasting pain that can continue after the rash has gone. It usually gets better eventually, but this can take anywhere from a few months to over a year. It is more common in older people and in those with other health conditions such as diabetes or a weakened immune system, and the risk is higher if your shingles symptoms were severe (NHS, Post-herpetic neuralgia).
The shingles vaccine and NHS eligibility
The shingles vaccine offered on the NHS is Shingrix, a non-live vaccine. It reduces the chance of getting shingles, and of getting serious problems if you do (NHS England; NHS, Shingles vaccine).
Who is eligible on the NHS
NHS shingles vaccine eligibility currently covers:
- Adults at age 65
- All adults aged 70 to 79
- Adults aged 18 and over with a severely weakened immune system
Most people are offered two doses given 6 to 12 months apart. People who are immunocompromised are given two doses 8 weeks to 6 months apart (NHS, Shingles vaccine).
From 1 September 2025, the vaccine was expanded to all severely immunosuppressed adults aged 18 and over, with no upper age limit, because severely immunosuppressed people are most at risk of serious illness and complications from shingles (NHS England).
How effective is the Shingrix vaccine?
In phase 3 clinical trials, the efficacy of the two-dose Shingrix vaccine against shingles was estimated at 97.2% in immunocompetent adults aged 50 and over, and 91.2% in those aged 70 and over. Long-term follow-up showed efficacy against shingles of 71.7% to 83.9% at 6 to 11 years after vaccination (UKHSA, Green Book chapter 28a).
Check your eligibility with us in Rochdale
If you are wondering whether you qualify, or you fall outside the current NHS age bands and want to understand your options, we can help. Our pharmacists can talk you through the vaccine, check your eligibility and arrange vaccination. You can read more about the shingles vaccination service or book a consultation to discuss it in person.
We also run a full programme of seasonal and travel immunisations, from the flu vaccination to RSV and pneumococcal vaccines, so you can keep your protection up to date in one place.
Frequently asked questions
Can you get shingles if you never had chickenpox?
Shingles is caused by the varicella-zoster virus reactivating after a previous chickenpox infection. Anyone who has had chickenpox is at risk of shingles later in life, because the virus stays dormant in the body and can reactivate when immunity falls (UKHSA blog).
Is shingles contagious?
You cannot spread shingles to other people. However, someone could catch chickenpox from you if they have not had it before, as the same virus causes both conditions (NHS, Shingles).
How long does shingles last?
The rash can take up to four weeks to heal. Some people develop postherpetic neuralgia, long-lasting pain that can continue after the rash has gone and may take from a few months to over a year to settle (NHS, Shingles; NHS, Post-herpetic neuralgia).
Can I have the shingles vaccine if I am younger than 65?
On the NHS, adults are eligible at age 65, all adults aged 70 to 79 are eligible, and adults aged 18 and over with a severely weakened immune system are eligible (NHS, Shingles vaccine). If you fall outside these bands, book a consultation and we can talk through your options.
How effective is the shingles vaccine?
In clinical trials, the two-dose Shingrix vaccine was estimated to be 97.2% effective against shingles in adults aged 50 and over, and 91.2% effective in those aged 70 and over, with protection of 71.7% to 83.9% maintained at 6 to 11 years after vaccination (UKHSA, Green Book chapter 28a).
Book your shingles consultation
Shingles risk rises as immunity declines with age, and the vaccine is the most effective way to lower your chance of getting it and of developing complications. To check whether you are eligible and arrange your vaccination, book a consultation with our pharmacy team in Rochdale.
Sources
- NHS, Shingles
- NHS, Post-herpetic neuralgia
- NHS, Shingles vaccine
- UKHSA, Shingles (herpes zoster): the Green Book chapter 28a
- UKHSA, Shingles immunisation programme: information for healthcare practitioners
- UK Health Security Agency blog, symptoms of shingles and the connection to chickenpox
- NHS England, Shingles vaccine to be offered to hundreds of thousands more immunosuppressed adults
0 comments