Is Shingles Contagious?

The answer to the question of whether or not shingles (herpes zoster) is contagious is quite succinct and emphatic. “Shingles cannot be passed from 1 person to another,” states the CDC on its website.¹

However, the potential for exposing a person to another viral infection that leads to shingles is very real. It all comes down to the innate nature of the virus. Here’s why:

The root cause of herpes zoster (HZ) is a reactivation of the varicella zoster virus (VZV) that has remained dormant in the patient’s peripheral nervous system since an earlier bout of the chickenpox. Consequently, anyone who has had chickenpox is at risk of developing shingles at some point in their life. But if they do, they cannot pass it along to anyone else.

What they can pass along is VZV to anyone who has not had chickenpox or received the varicella vaccine. Individuals at greatest risk in this category are infants, young children, pregnant women, and individuals who are immunocompromised. If exposed to VZV, they are likely to develop chickenpox.

Transmission of VZV occurs only during the active blister phase of shingles. Within days of onset, small, fluid-filled blisters appear in clusters surrounded by red skin in the affected area on the body. Blisters continue to erupt and ooze for up to a week, at which point they dry up and crust over.

The VZV can pass to another person that comes in physical contact with the blisters’ fluid. What happens next depends on that person’s personal health history. There are 2 scenarios:

Scenario 1: The person has never had chickenpox or been vaccinated against it. It is likely that they will become infected with the virus as a result of their exposure and develop chickenpox. Once the virus has run its course, it will go dormant in their body. Any future case of shingles will be the result of that virus reactivating.

Scenario 2: The person has already had chickenpox or the vaccine. They do not become infected from their exposure to shingles because the virus is already in their body or they are immune to it. If they had chickenpox and later develop shingles, it will be because the dormant virus reactivated on its own.

Simple steps can be taken to help prevent the spread of VZV. They include avoiding touching or scratching the rash, covering the rash, avoiding contact with individuals at greatest risk from chickenpox, and frequent handwashing.

In addition to the pain and discomfort associated with shingles, the infection can lead to a number of serious complications. Primary among them is postherpetic neuralgia. Other possible complications include postherpetic itch, vision loss related to herpes zoster ophthalmicus, and gastrointestinal issues like Crohn’s disease and inflammatory bowel disease resulting from enteric zoster.

Shingles and its complications can be avoided completely through vaccination. Shingrix is recommended by the CDC’s Advisory Committee on Immunization Practices for use in people aged 50 and older. Its efficacy rate across all age groups is greater than 90%, although its incidence of side effects is higher than the other available vaccine, Zostavax. Shingrix is administered in 2 doses given 2 to 6 months apart, and it can be used regardless of a past episode of herpes zoster or previous vaccination with Zostavax.

References:

• National Center for Immunization and Respiratory Diseases, Division of Viral Diseases. Transmission. CDC. July 1, 2019. https://www.cdc.gov/shingles/about/transmission.html.