Varicella (Chickenpox) Organism-Specific Therapy

Updated: Jul 12, 2021
  • Author: Richard Lichenstein, MD; Chief Editor: Thomas E Herchline, MD  more...
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Organism-Specific Therapy

Treatment regimens for varicella-zoster virus (VZV) are provided below, including those for acyclovir, varicella virus vaccine live (Varivax), and varicella-zoster immune globulin (VariZIG).

Varicella-zoster virus (VZV)

Adults with encephalitis, pneumonia, or immunocompromised patients [1] :

Adults and children >12 years at increased risk for complications:

  • Acyclovir 800 mg PO 5 times daily x 5-7 days

  • Valacyclovir 20 mg/kg PO 3 times daily for 5 days; not to exceed 1 g/dose 3 times daily

Children >1 year who have encephalitis or pneumonia or are immunocompromised [4] :

  • Acyclovir 500 mg/m2 IV q8h for 7-10 days

Children 2-12 years who are at increased risk for complications:

  • Acyclovir 20 mg/kg PO 4 times daily for 5 days; not to exceed 3200 mg/day

  • Valacyclovir  20 mg/kg PO 3 times daily for 5 days; not to exceed 1 g/dose 3 times daily 

Children < 1 year who are immunocompromised:

  • 30 mg/kg/day IV in 3 divided doses for 7-10 days

Children 2-12 years with uncomplicated varicella:

  • Use of acyclovir is not routinely recommended

  • Acyclovir use does not affect incidence of pruritus, complications, or secondary transmission in children with varicella

  • Consider acyclovir use in secondary household cases, in which the disease is usually more severe

Varicella virus vaccine live(Varivax)

Used for vaccination against varicella in individuals 1 y and older. [1]

Children 1-12 years:

  • Administer first dose of 0.5 mL subcutaneously at age 12-15 mo

  • Second dose is routinely administered at age 4-6 y; second dose can be given at any age as long as it has been at least 3mo since first dose

Adults and children 13 years and older with no evidence of immunity [1] :

  • Administer 2 doses of 0.5 mL subcutaneously 4-8wk apart

Varicella-zoster immune globulin(VZIG) post exposure

  • Varicella zoster immune globulin (VariZIG by Cangene) is indicated for administration to high-risk individuals within 10 days (ideally within 4 days) of chickenpox (varicella zoster virus) exposure. If VariZIG is unavailable, intravenous immunoglobulin (IVIG) can be used.

  • High-risk groups include the following:

    • Immunocompromised children and adults

    • Newborns of mothers with varicella shortly before or after delivery

    • Premature infants

    • Infants less than one year of age [6]

    • Adults without evidence of immunity

    • Pregnant women

  • VZIG is indicated in pregnant women for the prevention or reduction in severity of maternal infection within 10 days [5] (ideally within 96 hours of exposure to VZV). [2]

  • VZIG should be given to an infant if the mother develops varicella from 5 days before to 2 days after delivery

  • VZIG should be given to hospitalized premature infants of ≥28 wk gestation whose mothers have no history of varicella infection; also, VZIG should be given to hospitalized premature infants < 28 wk gestation or weighing ≤1000 g at birth regardless of maternal history when a significant exposure has occurred

  • Recommended dose is 125 IU/10 kg body weight, as follows:

    • < 2 kg: 62.5 IU I

    • 2.1-10 kg: 125 IU IM

    • 10.1-20 kg: 250 IU IM

    • 20.1-30 kg: 375 IU IM

    • 30.1-40 kg: 500 IU IM

    • Children >40 kg and adults: 625 IU IM