Why do older people get shingles? The connection to weakened immunity

Oct 15, 2025 3 min read •

senior care Healthy Aging immunology

Over 99% of Americans born before 1980 have had chickenpox, and they carry the varicella-zoster virus (VZV) that can reactivate years later as shingles. This occurs most frequently in older adults due to a natural decline in the immune system's ability to keep the virus suppressed.

Quick Summary

Older people are more likely to get shingles because the varicella-zoster virus, which causes chickenpox, remains dormant in their bodies after recovery. As the immune system weakens with age, it can no longer keep the virus in check, allowing it to reactivate and cause the painful shingles rash.

Key Points

Dormant Virus: After having chickenpox, the varicella-zoster virus remains dormant in your nervous system for life, kept in check by your immune system.
Aging Immune System: As you get older, your immune system naturally weakens, a process called immunosenescence, making it less effective at suppressing the dormant virus.
Reactivation Trigger: When immunity wanes, the virus can reactivate, travel along nerve pathways, and cause the characteristic painful shingles rash.
Increased Risk with Age: The risk of shingles increases significantly with age, with most cases occurring in adults over 50.
Severe Complications: Older adults face a higher risk of severe complications, most notably postherpetic neuralgia (PHN), which is long-term nerve pain.
Vaccination is Key: The Shingrix vaccine is highly effective at preventing shingles and its complications and is recommended for adults 50 and older.

The dormant virus and waning immunity

Shingles, also known as herpes zoster, is caused by the varicella-zoster virus (VZV), the same virus that causes chickenpox. After a person recovers from chickenpox, VZV remains dormant in the body's nerve tissues. A healthy immune system typically keeps the virus suppressed. However, this can change with age.

The main reason older people are more susceptible to shingles is immunosenescence, the age-related decline of the immune system. As the immune system weakens, its ability to control the dormant VZV lessens, allowing the virus to reactivate and cause the characteristic painful, blistering rash.

Age-related risk factors for shingles

Besides immunosenescence, several other factors contribute to the increased risk of shingles in seniors:

Weakened immune system from other conditions: Chronic diseases common in older adults, such as diabetes and rheumatoid arthritis, can suppress the immune system and increase risk. Certain cancers like leukemia and lymphoma also pose a higher risk.
Immunosuppressive medications: Medications commonly taken by seniors, including corticosteroids and transplant-related drugs, can weaken the immune response and trigger VZV reactivation.
Stress and illness: Temporary stressors like severe illness, surgery, or psychological stress can reduce immune function, potentially allowing the virus to reactivate.

Symptoms and potential complications

Shingles can be more severe in older adults and may lead to long-term health issues. Recognizing symptoms early is vital.

Symptoms of a shingles outbreak

Symptoms often progress through stages:

Initial sensations of tingling, burning, or numbness on one side of the body.
Systemic symptoms like fever, headache, and chills.
Development of a red, blistering rash in a strip-like pattern within a few days.
Intense pain, itching, or sensitivity in the affected area.

Common complications in seniors

Postherpetic neuralgia (PHN): The most frequent complication, characterized by chronic, severe nerve pain in the area of the rash that can last for months or years after healing. The likelihood and severity of PHN increase with age.
Ophthalmic shingles: If shingles affects the eye area, it can result in permanent vision loss without prompt treatment.
Neurological issues: Rare complications include brain inflammation, facial paralysis, or problems with hearing and balance.
Bacterial skin infections: Blisters can become infected by bacteria if not properly cared for, potentially leading to scarring.

Comparison of shingles risk factors


Risk Factor	How it Affects Vulnerability	Impact on Older Adults	Impact on Young Adults
Age	Gradual decline in cellular immunity (immunosenescence) over time.	Primary risk factor; significantly higher likelihood of shingles and severe complications.	Risk is low unless immune system is suppressed by other factors.
Immune-Suppressing Conditions	Diseases like HIV/AIDS and certain cancers weaken the immune response.	Higher susceptibility due to co-morbidities and natural aging of the immune system.	High risk if they have an immunocompromising condition.
Medications	Drugs such as long-term corticosteroids and chemotherapy suppress the immune system.	Can be a significant risk factor for seniors taking multiple medications.	Can be a risk factor, though less common than in older adults.
Stress and Illness	Mental or physical stress temporarily weakens the immune system.	More pronounced effect due to a generally weaker baseline immune system.	Can be a temporary trigger, but less likely to cause a severe or lasting outbreak.

Prevention through vaccination

Vaccination is a highly effective method to prevent shingles and its complications in older adults. The CDC recommends the Shingrix vaccine for adults aged 50 and older, administered in two doses. This vaccine shows high efficacy in preventing shingles and postherpetic neuralgia (PHN) and provides lasting protection. It is recommended even for those who have previously had shingles. For more information, visit the {Link: CDC's Shingles Vaccination website https://www.cdc.gov/shingles/vaccines/index.html}.

What to do if you suspect shingles

If an older adult shows potential shingles symptoms, prompt medical attention is crucial. Starting antiviral treatment within 72 hours of the rash appearing can help reduce the severity, duration, and risk of complications.

Conclusion

The increased risk of shingles in older adults is due to the persistent varicella-zoster virus and the natural weakening of the immune system with age. This allows the virus to reactivate. Understanding these risks and considering preventative measures like the Shingrix vaccine are important for senior health.

Frequently Asked Questions

Shingles, or herpes zoster, is caused by the same virus that causes chickenpox, the varicella-zoster virus (VZV). After recovering from chickenpox, the virus stays dormant in your nervous system. Shingles occurs when this dormant virus reactivates later in life.

The risk of shingles increases with age due to the natural weakening of the immune system, known as immunosenescence. This decline makes it harder for the body to keep the dormant VZV from reactivating and causing the painful rash.

Yes. Beyond natural aging, other factors that weaken the immune system, such as chronic illnesses (e.g., HIV, cancer), immunosuppressive medications, chemotherapy, and even significant stress, can all increase your risk of getting shingles.

Early symptoms often include a burning, tingling, or itching sensation on one side of the body or face. This can occur several days before a characteristic blistering rash appears. Other symptoms may include fever, headache, or chills.

PHN is the most common complication of shingles, especially in older adults. It is a condition where severe, long-term nerve pain persists in the area where the shingles rash occurred, even after the rash has healed.

It is possible, though the risk is significantly lower than for those who had a natural chickenpox infection. The current shingles vaccine, Shingrix, is still recommended for all adults 50 and older, regardless of their past chickenpox or vaccination history.

Yes. The CDC recommends two doses of the recombinant zoster vaccine (Shingrix) for all adults 50 years and older. It is highly effective at preventing shingles and its complications, including PHN.

It is important to contact a healthcare provider as soon as possible, ideally within 72 hours of the rash's onset. Prompt treatment with antiviral medication can reduce the severity and duration of the illness and minimize the risk of complications.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.