Indications for: VARIZIG

Postexposure prophylaxis of varicella in high risk individuals (include immunocompromised children and adults, newborns of mothers with varicella shortly before or after delivery, premature infants, neonates and infants <1 year old, adults without evidence of immunity, pregnant women). To reduce severity of varicella.

Clinical Trials:

Pregnant Women Exposed to Varicella Zoster Virus

A randomized, open-label, multicenter, active controlled clinical trial was conducted in 60 pregnant women without immunity to VZV (as confirmed by a latex agglutination test).

  • Patients were stratified on the basis of time from first exposure to varicella as follows:
    • 1 to 4 days post-exposure and,
    • 5 to 14 days post-exposure.
  • The women were randomly assigned into 1 of 3 study arms as follows:
    • a single IV dose of 125 IU/10 kg to a max dose of 625 IU of Varizig,
    • a single IM dose of 125 IU/10 kg to a max dose of 625 IU of Varizig or,
    • a single IM dose of 125 IU/10 kg to a max dose of 625 IU of VZIG (licensed comparator product).
  • Patients were followed for 42 days.
  • Incidence of clinical varicella was similar across all treatment groups with an overall incidence of 33%; however, in the subset of 28 patients with more than 24 hours exposure to varicella, the incidence of clinical varicella in the combined treatment groups was 64%.

High Risk Patients Exposed to Varicella Zoster Virus

An open-label, Expanded Access Protocol (EAP) conducted in the US was designed to provide Varizig to high risk individuals who were exposed to varicella zoster virus (VZV). The study was not designed to evaluate efficacy, however, the objective was to further assess and confirm the safety/efficacy of Varizig IM injection in the prevention or reduction of severity of complications from varicella infections in the indicated high risk populations. Initially, enrollment was limited to allow treatment with Varizig only within 96 hours of exposure, but later amended to a treatment window of 10 days post-exposure.

  • The incidence of clinical varicella (chickenpox lesions), was compared to predefined historical reference rates.
  • The incidence of severe varicella complications, including pneumonia, encephalitis, severe varicella with pox counts >100 pox, mortality and all complications was also evaluated.
  • The overall incidence of clinical varicella was evaluated in an interim analysis, where 10% (31/311) of high risk individuals exposed to VZV and treated with Varizig for all combined populations, for whom complete or partial efficacy data was available.
  • Clinical varicella was observed in 8.4% (13/154) of immunocompromised pediatric and adult patients, in 6.8 % (5/74) of pregnant women, in 14.8% (12/81) of infants and one healthy adult.
  • Clinical varicella was more common after prolonged VZV exposure.
  • The final report confirmed the efficacy results in the interim analysis.
  • Updated final results of clinical varicella was observed in 4.5% (12/269) of immunocompromised pediatric and adult patients, in 7.3% (10/137) of pregnant women, in 11.4% (12/105) of infants (including newborns, preterm infants, infants aged <1yr). 

Moreover, a comparison of the incidence of varicella based on the treatment window revealed that treatment between 5 and 10 days post-exposure was no different from treatment within 96 hours.

Adults and Children:

See full labeling. Administer one single-dose by IM inj ideally within 96 hours of exposure. Based on patient size: divide dose and give in ≥2 inj sites; max 3mL per inj site. Inject into deltoid muscle or anterolateral aspects of the upper thigh. Avoid gluteal region; if needed, only use upper, outer quadrant. ≤2kg: 62.5 IU; 2.1–10kg: 125 IU; 10.1–20kg: 250 IU; 20.1–30kg: 375 IU; 30.1–40kg: 500 IU; ≥40.1kg: 625 IU. Consider 2nd full dose for high risk patients with additional exposure >3 weeks after initial dose.

VARIZIG Contraindications:

IgA-deficiency with IgA antibodies and history of hypersensitivity. Previous severe reaction to human immune globulin.

VARIZIG Warnings/Precautions:

Risk for thrombotic events: in patients with history of atherosclerosis, multiple cardiovascular risk factors, advanced age, impaired cardiac output, prolonged immobilization periods, and/or known/suspected hyperviscosity. Risk for hyperviscosity (including those with cryoglobulins, fasting chylomicronemia/markedly high triglycerides, or monoclonal gammopathies); monitor baseline blood viscosity. Severe thrombocytopenia. Coagulation disorders. Have epinephrine inj (1:1000) available. Contains human albumin; potential risk for infection transmission (eg, viruses, Creutzfeldt-Jakob disease). Elderly. Pregnancy. Nursing mothers.

VARIZIG Classification:

Immune globulin.

VARIZIG Interactions:

May affect response to live virus vaccines; may defer until 3 months after Varizig administration.

Adverse Reactions:

Inj site pain, headache, chills, fatigue, rash, nausea; hypersensitivity reactions (discontinue if occurs).

Drug Elimination:

Half-life: 26.2 ± 4.6 days.

Generic Drug Availability:


How Supplied:

Single-use vial—1