What is the recommended chemoprophylaxis (medication used to prevent disease) for varicella (chickenpox)?

Recommended Chemoprophylaxis for Varicella (Chickenpox)

For the prophylaxis of chickenpox, varicella zoster immune globulin (VZIG) should be administered as soon as possible but within 96 hours after close contact with a patient who has chickenpox or shingles to susceptible individuals (those with no history of chickenpox or shingles or who have no detectable antibody against VZV). 1

Who Should Receive Chemoprophylaxis

High-Risk Susceptible Individuals

• Susceptible individuals are those with no history of chickenpox or shingles or who have no detectable antibody against VZV 1
• VZIG is particularly indicated for the following susceptible groups:
  • HIV-infected children and adults 1
  • Immunocompromised patients 2
  • Pregnant women 1
  • Newborns during the first 2 weeks of life 2
  • Preterm infants in the neonatal nursery 2

Timing of Administration

• VZIG must be administered within 96 hours after exposure to be effective 1
• Earlier administration within this window is preferred for optimal effectiveness 1

Specific Recommendations by Population

Immunocompetent Individuals

• Routine chemoprophylaxis is not recommended for healthy immunocompetent individuals 2
• For healthy adults and adolescents who are susceptible, post-exposure vaccination within 3 days may provide partial protection, but this is not considered standard chemoprophylaxis 3

Immunocompromised Individuals

• VZIG is the recommended prophylaxis for immunocompromised individuals 1
• Acyclovir is not routinely recommended for prophylaxis in these patients as data are lacking on its effectiveness for preventing chickenpox 1
• For children with altered cell-mediated immunity who develop varicella, early commencement of acyclovir treatment (not prophylaxis) is recommended 2

Pregnant Women

• VZIG is strongly recommended for VZV-susceptible, HIV-infected pregnant women within 96 hours after exposure to VZV 1
• If oral acyclovir is used instead (which is not first-line), VZV serology should be performed so the drug can be discontinued if the patient is seropositive for VZV 1

Children

• HIV-infected children who are asymptomatic and not immunosuppressed may receive live attenuated varicella vaccine at 12-15 months of age or later as prevention 1
• Varicella vaccine should NOT be administered to immunocompromised HIV-infected children due to the risk of disseminated viral infection 1
• For susceptible children who are immunocompromised, VZIG is the recommended prophylaxis 1

Important Considerations and Caveats

Limitations of Acyclovir for Prophylaxis

• Data are lacking on the effectiveness of acyclovir for preventing chickenpox in susceptible HIV-infected children or adults 1
• Effective protocols for prophylaxis against varicella with acyclovir are not yet established 4
• Acyclovir is primarily indicated for treatment rather than prophylaxis of varicella infections 5

Vaccination Considerations

• Household contacts (especially children) of susceptible HIV-infected persons should be vaccinated against VZV if they have no history of chickenpox and are seronegative for HIV, to prevent transmission to susceptible contacts 1
• Live attenuated varicella vaccine is contraindicated in pregnant women 3

Prevention of Exposure

• HIV-infected children and adults who are susceptible to VZV should avoid exposure to persons with chickenpox or shingles 1
• This is an important preventive measure in addition to chemoprophylaxis 1

No Prevention for Shingles

• No preventive measures or chemoprophylaxis are currently available for shingles (herpes zoster) 1
• No drug has been proven to prevent the recurrence of shingles in HIV-infected persons 1