Shingles is a viral infection caused by the varicella-zoster virus (VZV), the same virus responsible for chickenpox. After a chickenpox infection, VZV remains inactive within the body. It is possible to develop shingles more than once.
The Possibility of Recurrence
After chickenpox, the varicella-zoster virus remains dormant within nerve cells, specifically in the sensory ganglia. This latent virus can reactivate later in life, causing the characteristic shingles rash. While a prior shingles episode can boost the immune system’s response to VZV, this immunity is not absolute or permanent.
The immune system keeps the dormant virus in check, but its effectiveness can weaken over time. This allows the virus to reactivate, leading to another shingles episode. Although most people experience shingles only once, recurrence rates range from approximately 1.2% to 9.6% in the general population. For individuals with weakened immune systems, the recurrence rate can be higher, reaching up to 18%. The average time between a first shingles infection and a recurrent one is about two years for adults aged 45-54 and three years for those 55 and older.
Factors Influencing Recurrence
Factors can increase the likelihood of experiencing shingles more than once. Age is a significant factor, as the immune system naturally becomes less effective over time. The risk of recurrence increases for individuals over 50 years old.
A weakened immune system is a prominent risk factor for recurrent shingles. This can result from various health conditions, including HIV/AIDS, certain cancers, autoimmune diseases such as lupus, and chronic conditions like diabetes. Medications that suppress the immune system, such as immunosuppressants, chemotherapy, or high doses of corticosteroids, also increase the risk of VZV reactivation.
Physical or emotional stress can also contribute to a weakened immune response, potentially triggering VZV reactivation and recurrent shingles. Studies suggest a link between chronic, daily stress or highly stressful life events and an increased risk of shingles outbreaks. Other factors influencing recurrence include being female, experiencing severe pain or postherpetic neuralgia (PHN) during the initial episode, or having had shingles in the eye during a previous infection.
Preventive Measures
Vaccination is a primary and effective measure to reduce the risk of future shingles episodes. The Shingrix vaccine is recommended for adults 50 and older, and for immunocompromised adults aged 19 and above. This vaccine is administered in two doses.
Shingrix demonstrates high effectiveness in preventing shingles and its complications. Clinical trials show efficacy rates of approximately 97% in adults 50 and older and about 90% in adults 70 and older. Real-world studies also indicate strong protection, with two doses being about 74-76% effective against shingles and 84-91% effective against postherpetic neuralgia (PHN). The protection offered by Shingrix can last for over a decade. The vaccine is recommended even for individuals who have already had shingles, as it helps reduce the chance of recurrence.
Maintaining a healthy lifestyle can support overall immune system function. This includes a balanced diet, regular physical activity, stress management, and adequate sleep. These measures contribute to a robust immune system, helping to keep the dormant varicella-zoster virus in check.