Is shingles (herpes zoster) contagious?

Is Shingles Contagious?

Yes, shingles is contagious, but it is significantly less transmissible than chickenpox—approximately 20% as contagious—and can only spread varicella-zoster virus (VZV) to susceptible individuals through direct contact with fluid from active lesions or, rarely, through airborne transmission in healthcare settings. 1

Understanding the Transmission Mechanism

Shingles cannot directly cause shingles in another person. Instead, a person with shingles can transmit VZV to someone who has never had chickenpox or the varicella vaccine, which would cause chickenpox (not shingles) in that susceptible individual. 1 Shingles itself only occurs as a reactivation of dormant virus in someone who previously had chickenpox. 1, 2

How VZV Spreads from Shingles

• Direct contact with lesion fluid is the primary transmission route, requiring physical contact with the fluid from shingles vesicles. 1
• Airborne transmission is possible but primarily documented in healthcare settings where susceptible persons with no direct contact with the index patient have acquired infection. 3
• Household transmission risk is approximately 20% of the risk seen with chickenpox, based on household contact studies. 1

Contagious Period

The period of contagiousness begins 1-2 days before rash onset and continues until all lesions have dried and crusted, typically 4-7 days after rash onset. 1 For lesions that do not crust (macules and papules), contagiousness ends when no new lesions appear within a 24-hour period. 1

Important Distinctions by Patient Type

• Immunocompetent patients: Lesions typically crust within 4-7 days. 1, 4
• Immunocompromised patients: May experience slower healing (7-14 days or longer) and prolonged viral shedding, resulting in extended contagiousness. 1
• Disseminated shingles: Considered as infectious as chickenpox itself. 3
• Localized shingles: Much less infectious than chickenpox or disseminated disease. 3

High-Risk Populations to Protect

Individuals with shingles must avoid contact with:

• Pregnant women (at risk for severe disease and potential fetal complications) 3, 1
• Premature infants and neonates (especially those born <28 weeks' gestation or weighing ≤1,000 grams) 3
• Immunocompromised persons (including those on immunosuppressive therapy, with malignant disease, or immunodeficient) 3, 1
• Anyone without history of chickenpox or varicella vaccination 1

Practical Prevention Measures

To minimize transmission risk:

• Cover all lesions completely with clothing or dressings to prevent direct contact. 1, 4
• Wash hands frequently with soap and water. 1
• Use separate towels and pillows from household members. 1
• Avoid sharing personal items that may contact the rash. 1

Healthcare Setting Precautions

• Immunocompetent patients with localized shingles: Standard precautions with complete covering of lesions are required. 4
• Disseminated shingles or immunocompromised patients with shingles: Airborne and contact precautions are necessary until all lesions are dry and crusted. 4
• Healthcare workers with shingles: Must cover all lesions and be restricted from caring for high-risk patients until all lesions have dried and crusted. 1

Common Pitfalls to Avoid

• Assuming antiviral therapy immediately makes the patient non-contagious: Viral shedding continues until lesions are fully crusted, regardless of antiviral treatment. 1
• Inadequate covering of lesions: Even with localized disease, transmission can occur if lesions are not completely covered. 1
• Allowing premature return to work or contact with vulnerable individuals: Contagiousness persists until complete crusting occurs. 1, 4
• Failing to recognize prolonged contagiousness in immunocompromised patients: These individuals may shed virus for extended periods beyond the typical 4-7 days. 1
• Underestimating airborne transmission risk in healthcare settings: Although rare, airborne spread has been documented in hospitals, particularly affecting patients with no direct contact with the index case. 3