COVID-19 is caused by the SARS-CoV-2 virus, while shingles results from the varicella-zoster virus (VZV). Though distinct, emerging research suggests a connection between COVID-19 infection and shingles risk.
Understanding Shingles Reactivation
Shingles is a painful viral infection caused by the varicella-zoster virus (VZV), the same virus responsible for chickenpox. After a person recovers from chickenpox, VZV does not leave the body; instead, it remains dormant in nerve cells for the rest of their life. While dormant, the virus typically causes no immediate symptoms.
The immune system plays a significant role in keeping the latent VZV under control. However, this dormant virus can reactivate later in life, leading to shingles. Common factors that trigger this reactivation include aging, as the immune system naturally weakens with age, and periods of physical or emotional stress. Other contributing factors can include having a chronic disease or undergoing immunosuppressive therapies. Reactivation typically results in a painful rash that follows nerve pathways.
The Immune System Connection: How COVID-19 May Influence Shingles Risk
While COVID-19 does not directly cause shingles, emerging research indicates that infection with SARS-CoV-2 may increase the risk of VZV reactivation. Studies suggest that COVID-19 can create an immunosuppressive state, potentially favoring the reactivation of the dormant VZV.
One primary mechanism involves COVID-19’s impact on the immune system. SARS-CoV-2 infection can lead to immune dysregulation and lymphopenia, a reduction in lymphocyte count, which includes T-cells. Maintaining sufficient immunity is important for suppressing shingles, so a temporary weakening of the immune system by COVID-19 could allow VZV to reactivate.
Several large studies have observed an increased risk of shingles following a COVID-19 diagnosis, especially in individuals aged 50 years and older. For instance, a 2022 study found that people aged 50 years or older with COVID-19 had a 15% higher risk of developing shingles compared to those without COVID-19. This risk further increases to 21% for those over 50 who were hospitalized with COVID-19, suggesting a link between infection severity and shingles risk.
Recognizing Shingles and When to Seek Medical Help
Shingles typically presents with a characteristic painful rash that appears on one side of the body, often forming a stripe around the waist or on one side of the face, neck, chest, belly, or back. Before the rash appears, individuals may experience early symptoms such as deep, burning, or shooting nerve pain, itching, or tingling in the affected area, sometimes weeks or days in advance. The rash consists of blisters that usually scab over within 7 to 10 days and clear up within 2 to 4 weeks. Other general symptoms that can accompany the rash include fever, headaches, chills, or an upset stomach.
A potential complication of shingles is postherpetic neuralgia (PHN), which involves persistent nerve pain in the area where the rash occurred, even after it has healed. This pain can be severe, burning, sharp, or aching and may last for months or even years, significantly interfering with daily life. Other serious complications can include vision loss if shingles affects the eye, bacterial infection of the rash, or brain inflammation (encephalitis). It is important to seek medical attention if shingles is suspected, especially if the rash appears on the face, as early diagnosis and treatment with antiviral medications can help reduce symptom severity and lower the risk of complications.
Preventive Measures for Shingles
The most effective way to reduce the risk of shingles is through vaccination. The Centers for Disease Control and Prevention (CDC) recommends two doses of the recombinant zoster vaccine, Shingrix, for healthy adults aged 50 years and older. This recommendation applies whether or not an individual has previously had shingles or received an older shingles vaccine. Shingrix is highly effective, offering over 90% protection against shingles and postherpetic neuralgia in adults 50 and older with healthy immune systems.
Adults aged 19 years and older who are or will be immunocompromised due to disease or therapy are also recommended to receive two doses of Shingrix, given their higher risk of complications. The vaccine is administered as a shot in the upper arm, with the second dose typically given 2 to 6 months after the first. Beyond vaccination, general immune-supporting practices, such as maintaining a healthy diet and managing stress, can also contribute to overall immune health.