Herpes Zoster Airborne Precautions
Airborne precautions are required for disseminated herpes zoster and for immunocompromised patients with localized herpes zoster until disseminated infection is ruled out, but immunocompetent patients with localized herpes zoster require only standard precautions with complete covering of lesions. 1
Clinical Decision Algorithm
Step 1: Assess Disease Distribution and Immune Status
Disseminated herpes zoster (lesions in >3 dermatomes):
- Requires both airborne AND contact precautions regardless of immune status 1
- Must use negative air-flow rooms until all lesions are dry and crusted 1
- If negative air-flow rooms unavailable, isolate in closed rooms with no contact permitted for persons lacking varicella immunity 2
Localized herpes zoster in immunocompromised patients:
- Requires both airborne AND contact precautions until disseminated infection is ruled out 1, 2
- Immunocompromised patients may have prolonged viral shedding (7-14 days or longer vs. 4-7 days in immunocompetent patients) 3
- Continue precautions until all lesions are completely dry and crusted 1, 2
Localized herpes zoster in immunocompetent patients:
- Standard precautions with complete covering of lesions only 1
- No airborne precautions required 1
- Contact precautions are not mandatory but covering lesions completely is essential 1
Step 2: Healthcare Personnel Restrictions
Only healthcare personnel with documented evidence of varicella immunity should care for patients with disseminated or immunocompromised localized herpes zoster 1, 2
Evidence of immunity includes:
- Documentation of 2 doses of varicella vaccine 1
- Laboratory evidence of immunity 1
- Laboratory confirmation of prior disease 2
Healthcare workers with herpes zoster:
- Immunocompetent workers with localized zoster: cover all lesions completely and restrict from caring for high-risk patients until lesions are dry and crusted 3
- Workers with disseminated zoster or immunocompromised workers with localized zoster: exclude from duty until all lesions are dry and crusted 3
Step 3: Duration of Precautions
Precautions must continue until all lesions are completely dry and crusted 1, 3, 2
- Typical timeline: 4-7 days after rash onset in immunocompetent patients 3
- Extended timeline: 7-14 days or longer in immunocompromised patients 3
- For non-crusting lesions (macules/papules): until no new lesions appear within 24 hours 3
Transmission Risk Context
Herpes zoster is approximately 20% as contagious as chickenpox and primarily spreads through direct contact with lesion fluid 3
Airborne transmission is possible but primarily documented in healthcare settings, particularly affecting susceptible immunocompromised patients 3, 2
- Nosocomial transmission has occurred from patients, hospital staff, and visitors 3
- Environmental surfaces in patient rooms can be extensively contaminated with varicella-zoster virus 2
Common Pitfalls to Avoid
Do not assume localized disease in immunocompromised patients - always rule out disseminated infection before downgrading precautions 2
Do not discontinue precautions when antiviral therapy is started - viral shedding continues until lesions are fully crusted, and antivirals do not immediately render patients non-contagious 3, 2
Do not allow healthcare personnel without documented immunity to provide care, even briefly, to patients requiring airborne precautions 2
Do not use standard precautions alone for disseminated or immunocompromised localized cases - both airborne and contact precautions are required simultaneously 2
Do not inadequately cover lesions in localized immunocompetent cases - incomplete covering can lead to transmission even without airborne spread 3
Post-Exposure Management
Healthcare personnel exposed to uncovered lesions require monitoring days 8-21 after exposure for fever, skin lesions, and systemic symptoms 1, 2
Unvaccinated healthcare personnel without immunity who are exposed should be furloughed during days 8-21 after exposure 1, 2