Risk Factors for Developing Shingles

Virtually every person born prior to 1980 in the United States was infected with the highly contagious varicella zoster virus (VZV) before an effective vaccine was available. The virus causes varicella (chickenpox) and then settles into the dorsal root ganglia, where it remains dormant for decades before reactivating as herpes zoster (shingles). Consequently, almost every adult American is at risk for developing the painful condition.

There are various factors, however, that increase an individual’s risk for shingles. Some are related to a decline in VZV-specific immunity, but there are other reasons as well, including:

• Age. The chances of developing herpes zoster and associated complications, including postherpetic neuralgia and vision loss, increase considerably after the age of 50. This is due to a normal decline in a person’s immune system that occurs throughout the aging process. The risk of shingles continues to increase with each passing decade. For example, whereas about 1 in 3 Americans experience shingles during their lifetime, that ratio rises to 1 in 2 among people age 80 and older.
• Gender. Women are more likely to develop shingles than men, with pregnant and menopausal women being most vulnerable. Although the exact reason for this is not known, it’s thought to be related to normal hormonal changes that occur during the aforementioned periods in a women’s life, which affect the immune response.
• Race. Shingles is more common in people of non-Hispanic white ancestry than in those of African American ancestry. According to the CDC, herpes zoster is at least 50% less common in Blacks than in whites. One study concluded that elderly Blacks were up to 75% less likely to develop herpes zoster than elderly whites.¹
• Health. Certain medical conditions and medications that suppress an individual’s immune system can make them more susceptible to shingles. For example, patients with cancer (particularly leukemia and lymphoma) or HIV, as well as bone marrow and solid organ transplant recipients are at greater risk. Immunosuppressive medications like steroids, chemotherapy, and those related to organ transplants also increase an individual’s chances of developing shingles. People with suppressed or compromised immune systems are also more likely to develop a form of shingles called disseminated zoster. Additionally, the risk is higher for individuals with diabetes and those with inflammatory bowel disease.

Vaccination is the best way to reduce the chances of developing shingles. Shingrix is currently the only shingles vaccine distributed in the United States.

Approved by the FDA in 2017 for people age 50 and over, Shingrix is a nonliving vaccine made of a virus component. It is administered in 2 doses given 2 to 6 months apart.

Shingrix offers protection against shingles for more than 5 years and has proven to be over 90% effective across all target age groups. It has also been shown to reduce the length and severity of the infection, and lower the risk of complications.

Zostavax, the first available shingles vaccine, was removed from distribution in the United States by Merck in July 2020. The CDC recommends that patients who have previously received Zostavax should subsequently receive Shingrix. Providers are advised to consider the patient’s age and time since receipt of Zostavax to determine when to vaccinate with Shingrix, although the minimum interval should be 8 weeks.² 

References:

1. Schmader K, George LK, Burchett BM, Hamilton JD, Pieper CF. Race and stress incidence of herpes zoster in older adults. Journal of the American Geriatrics Society. 1998. doi: 10.1111/j.1532-5415.1998.tb02751.x
2. CDC. Frequently Asked Questions About Shingrix. Page last reviewed March 26, 2018. Accessed August 10, 2020. https://www.cdc.gov/vaccines/vpd/shingles/hcp/shingrix/faqs.html#:~:text=Frequently%20Asked%20Questions%20About%20Shingrix,-Related%20Pages&text=Shingrix%20is%20the%20preferred%20shingles,dose%20as%20soon%20as%20possible.