Varicella Zoster Immunoglobulin
Synonym :
VZIG
Mechanism :
VZIG is recommended for individuals who are at increased risk of severe varicella and who have no antibodies to varicella-zoster virus and who have significant exposure to chickenpox or herpes zoster. Those at increased risk include pregnant women with no previous history of the virus that become exposed to anyone who has come into contact with the virus and newborn babies of women who develop chicken pox in the period 7 days before to 7 days after delivery.
Indication :
- Chicken pox-passive prophylaxis
- Herpes zoster-passive prophylaxis
Contraindications :
If had a hypersensitivity reaction to a previous dose.
Dosing :
Most effective when administer within 48-96 hours after exposure; 125 units/10 kg (Maximum dose: 625 units, Minimum dose: 125 units. Do not give fractional doses).
Weight based VZIG dose:
Administer within 10 days after exposure (ideally within 4 days).
<2 kg: 62.5 IU IM
2.1-10 kg: 125 IU IM (1×125 unit vials)
10.1-20 kg: 250 IU IM (2×125 unit vials)
20.1-30 kg: 375 IU IM (3×125 unit vials)
30.1-40 kg: 500 IU IM (4×125 unit vials)
>40 kg: 625 IU IM (1×625 unit vial)
Consider a second full dose for high risk patients who have additional exposures to varicella >3 weeks after initial administration of the immunoglobulin.
Adverse Effect :
Local reactions such as pain, erythema and tenderness at the site of injection. Headache, fatigue, chills, rash, nausea and thrombosis have also been reported.
Interaction :
Administration of any immunoglobulin may raise antibody level to a number of micro-organisms, and this must be borne mind when interpreting antibody assays within 2-3 months of such administration. It may reduce the immunogenicity of live vaccines other than those against yellow fever and typhoid. If the immunoglobulin is given first an interval of at least 3 months should pass before giving a live vaccine other than those mentioned above. If the live vaccine is given first, at least 3 weeks should elapse before giving another live vaccine.
Hepatic Dose :
No dosage adjustments are recommended.