Shingles is a viral condition caused by the reactivation of the varicella-zoster virus (VZV), the same virus responsible for chickenpox. After recovering from chickenpox—whether in childhood or later—the virus remains dormant in the body and may become active again as shingles, particularly when the immune system is weakened.

Anyone who has had chickenpox or received the chickenpox vaccine is at risk for shingles, even if they never showed symptoms. The infection leads to a painful skin rash that often appears on one side of the face or body and typically begins with itching or pain before blisters form. These blisters usually crust over within 7 to 10 days.

While shingles affects around one in three people in the United States during their lifetime, most cases resolve without serious complications. However, in some situations, shingles can lead to long-term nerve pain, known as postherpetic neuralgia (PHN), or more rarely, conditions such as pneumonia, vision or hearing issues, or brain inflammation.

Can Shingles Be Genetic?

The exact role of genetics in shingles is still under study. Some research suggests that a family history—especially involving a parent or sibling—might raise your risk of developing shingles. One study found that individuals with two or more first-degree relatives with a history of shingles had almost three times the likelihood of developing the condition.

Scientists have also identified potential genetic markers, including variations in the HLA Complex P5 gene, that may influence susceptibility. While genetic testing can detect HLA variations, more research is needed to fully understand how genetics impact shingles risk.

Who Is Most Likely to Get Shingles?

Shingles can affect anyone who has had chickenpox, but certain groups are more vulnerable:

  • Older Adults: Risk increases with age, especially after age 50. Nearly half of those over 85 will experience shingles.
  • Ethnicity: Some studies suggest that people of non-Hispanic White ancestry have a higher likelihood of developing shingles.
  • Sex: Individuals assigned female at birth appear to be more frequently affected, making up nearly 60% of reported cases.

Is Shingles Contagious?

Shingles itself is not contagious, but the varicella-zoster virus can spread to people who haven’t had chickenpox or the chickenpox vaccine—causing them to develop chickenpox, not shingles. The virus spreads through direct contact with the fluid from shingles blisters.

To reduce the risk of transmission:

  • Keep rash areas covered
  • Avoid close contact with:
    • Infants under 1 year
    • Pregnant individuals
    • People with weakened immune systems

Risk Factors That Increase the Likelihood of Shingles

Weak Immune System

People with compromised immune function are more likely to get shingles and experience complications. This includes those with chronic illnesses or undergoing medical treatments that suppress the immune system.

Cancer

Individuals with cancer—especially blood cancers like leukemia or lymphoma—are at higher risk of developing shingles, particularly within the first year following diagnosis.

HIV (Human Immunodeficiency Virus)

HIV severely weakens the immune system, and those with HIV are 12–17 times more likely to develop shingles compared to the general population.

Diabetes

People with type 1 or type 2 diabetes face about 1.6 times the risk of shingles, possibly due to how the condition affects immune response.

Immunosuppressive Treatments

Medications such as steroids and therapies like chemotherapy or radiation can suppress immune function. Organ and bone marrow transplant recipients are also at increased risk of shingles.

Physical Injury

Some studies suggest physical trauma may trigger the reactivation of VZV in older adults, although this connection requires more research.

Stress

Chronic stress or emotional trauma may contribute to shingles outbreaks, particularly in individuals over 50. However, more data is needed to confirm this link.

Prevention: Shingles Vaccine

The shingles vaccine, Shingrix, is recommended for:

  • Adults over 50
  • Adults aged 19 and older with weakened immune systems

Shingrix is administered in two doses spaced two to six months apart and has proven effective at preventing shingles and reducing the risk of PHN.

Summary

Shingles is a painful condition caused by the reactivation of the varicella-zoster virus. While anyone who has had chickenpox is at risk, older adults, individuals with chronic conditions like cancer, HIV, and diabetes, and those undergoing immune-suppressing treatments face increased vulnerability.

Though not contagious in the same way as chickenpox, shingles can still spread VZV to others. Prevention through vaccination and understanding risk factors are key strategies in reducing the impact of this disease.