Is Shingles Contagious?
Yes, shingles is contagious, but only to individuals who have never had chickenpox or have not been vaccinated against varicella-zoster virus (VZV), and it transmits the virus as chickenpox, not as shingles. 1
Mechanism of Transmission
Shingles transmits VZV through direct contact with vesicular fluid from active skin lesions or through inhalation of aerosolized particles from these lesions. 1 The virus does not spread through respiratory secretions as readily as primary varicella (chickenpox), making shingles significantly less contagious than chickenpox. 1
Key Transmission Facts:
- Susceptible individuals exposed to shingles will develop chickenpox, not shingles, as shingles only occurs from reactivation of latent virus in someone who previously had chickenpox. 1, 2
- Localized shingles is much less infectious than chickenpox or disseminated shingles. 1
- Disseminated shingles (multi-dermatomal or visceral involvement) is as contagious as chickenpox. 1
Period of Contagiousness
Patients with shingles remain contagious from the time vesicles appear until all lesions have completely crusted over, typically 4-7 days after rash onset in immunocompetent individuals. 1, 3
- Immunocompromised patients may remain contagious longer due to prolonged viral shedding and delayed lesion healing. 1
- Breakthrough varicella (shingles in vaccinated individuals) is also contagious, though typically milder with fewer lesions. 1
High-Risk Populations Requiring Protection
Individuals Who Should Avoid Exposure:
- Pregnant women who are VZV-susceptible (no history of chickenpox or vaccination) should receive varicella-zoster immune globulin (VZIG) within 96 hours of exposure. 1, 3
- Immunocompromised patients (HIV-infected, cancer patients, transplant recipients, those on immunosuppressive therapy) who are VZV-susceptible should receive VZIG within 96 hours of close contact. 1, 3
- Newborns and infants too young for vaccination are at risk if exposed. 1
- Healthcare personnel who are VZV-susceptible should avoid caring for patients with active shingles. 1
Infection Control Measures
Patients with active shingles should avoid contact with susceptible individuals until all lesions have crusted. 3 This is particularly critical in healthcare settings where nosocomial transmission can be life-threatening to vulnerable patients. 1
Healthcare Setting Precautions:
- Localized shingles requires standard and contact precautions until lesions are crusted. 1
- Disseminated shingles requires airborne and contact precautions, similar to chickenpox. 1
- Both localized and disseminated shingles have been documented as sources of nosocomial VZV transmission in hospitals and long-term care facilities. 1
Special Considerations for Older Adults and Immunocompromised Patients
Immunocompromised patients are at significantly higher risk for severe, disseminated disease with prolonged viral shedding, making them more contagious for extended periods. 1, 2 These patients may develop:
- New lesions continuing for 7-14 days (versus 4-6 days in immunocompetent hosts). 3
- Chronic ulcerations with persistent viral replication without adequate antiviral therapy. 3
- Visceral involvement including pneumonia, hepatitis, and encephalitis. 2
Older adults with shingles are contagious through the same mechanisms but may have more severe disease and complications, increasing the duration of contagiousness. 4, 5
Common Pitfalls to Avoid
- Do not assume shingles is non-contagious simply because it is localized—it can still transmit VZV to susceptible individuals through direct contact. 1, 6
- Do not allow susceptible pregnant women or immunocompromised individuals near patients with active shingles, even if lesions appear mild. 1
- Do not discontinue isolation precautions until ALL lesions are completely crusted, not just when new lesions stop appearing. 1, 3
- Remember that household contacts of immunocompromised VZV-susceptible individuals should be vaccinated to prevent transmission. 1