What are the guidelines for contact precautions with herpes zoster?

Contact Precautions for Herpes Zoster

For immunocompetent patients with localized herpes zoster, standard precautions with complete covering of all lesions are sufficient; however, for disseminated herpes zoster or any herpes zoster in immunocompromised patients, both airborne and contact precautions are required until all lesions are dry and crusted. 1, 2

Precautions Based on Patient Status

Immunocompetent Patients with Localized Herpes Zoster

• Standard precautions with complete covering of lesions are adequate 1, 2
• No special airborne isolation is required as long as lesions can be completely covered 3
• Maintain these precautions until all lesions are dry and crusted 1, 2

Disseminated Herpes Zoster (Any Patient)

• Both airborne precautions (negative air-flow rooms) AND contact precautions are mandatory 1, 2
• Keep precautions in place until all lesions are dry and crusted 1, 2
• If negative air-flow rooms are unavailable, isolate patients in closed rooms with no contact with persons lacking varicella immunity 1, 3

Immunocompromised Patients with Localized Herpes Zoster

• Treat as disseminated disease until disseminated infection is ruled out 1, 2, 3
• Require both airborne and contact precautions 1, 2
• This includes patients on steroid therapy >2 mg/kg body weight or total of 20 mg/day prednisone equivalent 1
• Maintain precautions until all lesions are dry and crusted 1

Healthcare Personnel Requirements

Immunity Requirements

• Only healthcare personnel with documented evidence of immunity to varicella should care for patients with confirmed or suspected herpes zoster 1, 2, 3
• Evidence of immunity includes: documentation of 2 doses of varicella vaccine, laboratory evidence of immunity, or laboratory confirmation of disease 3

Post-Exposure Management

• Healthcare personnel with 2 doses of vaccine who are exposed to varicella-zoster virus (including uncovered localized herpes zoster lesions) should be monitored daily during days 8-21 after exposure for fever, skin lesions, and systemic symptoms 1, 2, 3
• Healthcare personnel with 1 dose of vaccine should receive the second dose within 3-5 days after exposure (if 4 weeks have elapsed since first dose) 1
• Unvaccinated healthcare personnel without evidence of immunity should be furloughed from work during days 8-21 after exposure and receive post-exposure vaccination as soon as possible 1

Duration of Precautions

• Maintain all precautions until lesions are completely dry and crusted 1, 2, 3
• This typically takes 4-7 days after rash onset in immunocompetent hosts 2
• In immunocompromised patients, lesion crusting may take longer 1

Transmission Considerations

Definition of Exposure

• Close indoor contact (same room) or face-to-face contact 1, 3
• Experts differ on duration: some suggest >5 minutes, others >1 hour; all agree transitory contact does not constitute significant exposure 1, 3
• Transmission occurs through direct contact with lesions or inhalation of aerosols from vesicular fluid 2, 4

Infectivity Patterns

• Localized herpes zoster is much less infectious than varicella or disseminated herpes zoster 1
• Transmission from localized herpes zoster is more likely after close contact, such as in household settings 1

Common Pitfalls to Avoid

• Failing to recognize that localized zoster in immunocompromised patients requires airborne and contact precautions until disseminated infection is ruled out 2, 3
• Allowing healthcare personnel without documented immunity to care for herpes zoster patients 2, 3
• Discontinuing precautions before all lesions are completely dry and crusted 1, 2
• Not maintaining closed-room isolation when negative air-flow rooms are unavailable for disseminated cases 1, 3
• Overlooking potential transmission to susceptible individuals, especially pregnant women and immunocompromised patients 2