Varicella Virus Vaccine

• Prevention of Varicella (Chickenpox):
  Active immunization to prevent varicella infection in susceptible individuals, including children aged 12 months and older, adolescents, and adults without prior immunity.
• Post-exposure Prophylaxis:
  Administration within 3 to 5 days after exposure to varicella-zoster virus to prevent or modify disease in susceptible individuals.
• Off-label Use:
  Occasionally used in certain immunocompromised patients with mild immune suppression, under specialist supervision.

• Route: Subcutaneous injection.
• Schedule:
• Children (12 months to 12 years): Two doses of 0.5 mL each, administered 3 months apart (minimum interval of 4 weeks).
• Adolescents (≥13 years) and Adults: Two doses of 0.5 mL each, administered 4 to 8 weeks apart.
• Post-exposure: Single dose administered within 3 to 5 days of exposure.
• Special Populations:
  No dose adjustment for elderly. Contraindicated in severe immunosuppression.

The vaccine contains live attenuated varicella-zoster virus that replicates locally after administration, inducing both humoral and cellular immune responses. This immune activation prepares the body to recognize and effectively combat wild-type varicella virus upon exposure, preventing infection or reducing disease severity.

• Absorption: Not applicable; vaccine acts locally.
• Distribution: Local replication in lymphoid tissue.
• Metabolism & Excretion: The attenuated virus is cleared by host immune mechanisms; no systemic metabolism or excretion.

• Pregnancy: Contraindicated; live vaccine with potential fetal risk. Women should avoid pregnancy for at least 1 month post-vaccination.
• Lactation: Limited data; no known risks; breastfeeding is not a contraindication.

• Vaccine, Live Attenuated Viral Vaccine.

• Hypersensitivity to vaccine components.
• Severe immunodeficiency.
• Pregnancy.
• Moderate to severe acute illness.

• Use caution in mild immunosuppression.
• Risk of vaccine-strain varicella infection in immunocompromised.
• Monitor for hypersensitivity reactions.
• Avoid during pregnancy.

• Common: Injection site pain, redness, swelling; mild rash; fever.
• Rare: Anaphylaxis; vaccine-related varicella infection; thrombocytopenia.

• Immunosuppressants may reduce efficacy and increase infection risk.
• Avoid concurrent live vaccines unless given simultaneously or separated by ≥4 weeks.

• Two-dose regimen recommended for better protection.
• Emphasis on catch-up vaccination for older children and adults.
• Post-exposure vaccination to control outbreaks endorsed.

• Store refrigerated at 2°C–8°C.
• Protect from light; do not freeze.
• Reconstitute immediately before use and use promptly.