Type: Measles, Mumps, Rubella, and Varicella Virus Vaccine Live
Form: Lyophilized powder for injection (0.5 mL/dose after reconstitution)
Manufacturer: Merck Canada Inc.
Indications and Clinical Use
Indication: Prevention of measles, mumps, rubella, and varicella in children 12 months through 12 years of age.
Age Range: Primarily indicated for children 12 months to 6 years but may be used up to 12 years based on component vaccines' efficacy.
Contraindications
Hypersensitivity: Known hypersensitivity to any component, including gelatin and neomycin.
Immunodeficiency: Blood dyscrasias, leukemia, lymphomas, immunosuppressive therapy, or primary/acquired immunodeficiency states.
Pregnancy: Should not be administered to pregnant females; pregnancy should be avoided for 3 months following vaccination.
Active Tuberculosis: Contraindicated in individuals with untreated tuberculosis.
Febrile Illness: Postpone vaccination in individuals with active febrile illness (>38.5 °C).
Warnings and Precautions
General: Administer subcutaneously; not for intravenous use.
Anaphylaxis: Immediate availability of epinephrine is recommended.
Transmission: Theoretical risk of transmission of vaccine virus, particularly varicella, to high-risk individuals.
Febrile Seizures: Higher incidence noted in children 12 to 23 months old.
Special Populations: Use with caution in individuals with a history of convulsions or cerebral injury, and avoid stress due to fever.
Adverse Reactions
Very Common (≥10%): Fever ≥38.9°C, injection site erythema or pain/tenderness/soreness.
Common (≥1% and <10%): Upper respiratory infection, rash, diarrhea, vomiting.
Uncommon (≥0.1% and <1%): Febrile seizure, somnolence, nasal congestion, cough.
Rare (≥0.01% and <0.1%): Lymphadenopathy, allergic reactions, conjunctivitis, ear pain.
Other: Post-marketing reports of encephalitis, thrombocytopenia, anaphylaxis, Guillain-Barré syndrome.
Drug Interactions
Concomitant Use: May be administered with certain vaccines like Haemophilus b conjugate, hepatitis B, and pneumococcal conjugate vaccines. Avoid immune globulins within 1 month before or after vaccination.
Salicylates: Avoid use for 6 weeks after vaccination due to Reye Syndrome risk.
Dosage and Administration
Dose: 0.5 mL subcutaneous injection.
Schedule: Single dose for children 12 months to 12 years. If a second dose is needed, administer at least 1 month apart.
Reconstitution: Use provided sterile diluent. Administer immediately after reconstitution or within 30 minutes if stored at room temperature.
Storage and Stability
Unreconstituted Vaccine: Store refrigerated at 2°C to 8°C or in a freezer above -50°C. Protect from light.
Reconstituted Vaccine: Use within 30 minutes; do not freeze.
Clinical Trials and Efficacy
Efficacy: Immunogenicity studies demonstrate robust antibody responses comparable to individual MMR and varicella vaccines.
Post-Exposure Prophylaxis: No specific data, but measles and varicella vaccines may provide protection if administered within 3 days of exposure.
