Clinical Studies: In clinical trials, varicella virus vaccine live (Oka/Merck) [hereafter called, varicella vaccine (Oka/Merck)] was administered to over 17,000 healthy children, adolescents, and adults. Varicella vaccine (Oka/Merck) was generally well tolerated.
In a double-blind placebo-controlled study among 956 healthy children and adolescents, 914 of whom were serologically confirmed to be susceptible to varicella, the only adverse reactions that occurred at a significantly greater rate in vaccine recipients than in placebo recipients were pain and redness at the injection site and varicella-like rash.
Children 1 to 12 Years of Age: One-Dose Regimen in Children: In clinical trials involving approximately 8900 healthy children monitored for up to 42 days after a single dose of varicella vaccine (Oka/Merck), fever, injection-site complaints, or rashes were reported in decreasing order of frequency as follows: injection-site complaints (pain/soreness, swelling and/or erythema, rash, pruritus, hematoma, induration, stiffness); fever ≥102°F (38.9°C) oral; varicella-like rash (generalized, median 5 lesions); varicella-like rash (injection site, median 2 lesions).
Clinical safety of refrigerator-stable varicella vaccine (Oka/Merck) (n=635) was compared with that of the licensed frozen formulation of varicella vaccine (Oka/Merck) (n=323) for 42 days post-vaccination in children 12 to 23 months of age. The safety profiles were comparable for the two different formulations. Pain/tenderness/soreness and erythema were the most commonly reported local reactions. The most common systemic adverse events (reported by ≥10% of subjects, irrespective of causality) were reported in decreasing order of frequency as follows: fever ≥102.0°F (38.9°C) oral; upper respiratory infection; otitis media; cough; rhinorrhea and irritability. Six subjects reported serious adverse events.
Two-Dose Regimen in Children: In a clinical trial, 981 children received 2 doses of varicella vaccine (Oka/Merck) 3 months apart and were actively followed for 42 days after each dose. The 2-dose regimen of varicella vaccine had a safety profile comparable to that of the 1-dose regimen. The overall incidence of injection-site clinical complaints (primarily erythema and swelling) observed in the first 4 days following vaccination was 25.4% Postdose 2 and 21.7% Postdose 1, whereas the overall incidence of systemic clinical complaints in the 42-day follow-up period was lower Postdose 2 (66.3%) than Postdose 1 (85.8%).
Adolescents and Adults 13 Years of Age and Older: In clinical trials involving approximately 1600 healthy adolescents and adults, the majority of whom received two doses of varicella vaccine (Oka/Merck) and were monitored for up to 42 days after any dose, fever, injection-site complaints, or rashes were reported in decreasing order of frequency as follows: injection-site complaints (soreness, erythema, swelling, rash, pruritus, pyrexia, hematoma, induration, numbness); fever ≥100°F (37.8°C) oral; varicella-like rash (generalized, median 5 lesions); varicella-like rash (injection site, median 2 lesions).
The following additional side effects have been reported regardless of causality since the vaccine has been marketed: Body As A Whole: Anaphylaxis (including anaphylactic shock) and related phenomena such as angioneurotic edema, facial edema, and peripheral edema; anaphylaxis in individuals with or without an allergic history.
Eye Disorders: Necrotizing retinitis (reported only in immunocompromised individuals).
Gastrointestinal Disorders: Nausea; vomiting.
Hemic and Lymphatic System: Aplastic anemia; thrombocytopenia (including idiopathic thrombocytopenic purpura (ITP)), lymphadenopathy.
Infections and Infestations: Varicella (vaccine strain).
Nervous/Psychiatric: Encephalitis†; cerebrovascular accident; transverse myelitis; Guillain-Barré syndrome; Bell's palsy; ataxia; febrile and non-febrile seizures; aseptic meningitis; meningitis†; dizziness; paresthesia; irritability.
Respiratory: Pharyngitis; pneumonia/pneumonitis; upper respiratory tract infection.
Skin: Stevens-Johnson syndrome; erythema multiforme; Henoch-Schönlein purpura; secondary bacterial infections of skin and soft tissue, including impetigo and cellulitis; herpes zoster†.
†Cases caused by wild-type varicella or vaccine strain varicella have been reported in immunocompromised or immunocompetent individuals.