Varivax Side Effects

Clinical Studies: Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a vaccine cannot be directly compared to rates in the clinical trials of another vaccine and may not reflect the rates observed in clinical practice. Vaccine-related adverse reactions reported during clinical trials were assessed by the study investigators to be possibly, probably, or definitely vaccine-related and are summarized as follows.
In clinical trials, varicella vaccine (Oka/Merck) was administered to over 11,000 healthy children, adolescents, and adults.
In a double-blind, placebo-controlled study among 914 healthy children and adolescents who were serologically confirmed to be susceptible to varicella, the only adverse reactions that occurred at a significantly (p<0.05) greater rate in vaccine recipients than in placebo recipients were pain and redness at the injection site.
Children 1 to 12 Years of Age: One-Dose Regimen in Children: In clinical trials involving healthy children monitored for up to 42 days after a single dose of varicella vaccine (Oka/Merck), the frequency of fever, injection-site complaints, or rashes were reported as shown in Table 2: (See Table 2.)

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In addition, adverse events occurring at a rate of ≥1% are listed in decreasing order of frequency: upper respiratory illness, cough, irritability, fatigue, disturbed sleep, diarrhea, loss of appetite, vomiting, otitis, headache, malaise, abdominal pain, other rash, nausea, chills, lymphadenopathy, myalgia, lower respiratory illness, allergic reactions (including allergic rash, hives), stiff neck, arthralgia, itching.
Pneumonitis has been reported rarely (<1%) in children vaccinated with varicella vaccine (Oka/Merck).
Febrile seizures have occurred at a rate of <0.1% in children vaccinated with varicella vaccine (Oka/Merck).
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 postvaccination in U.S. children 12 to 23 months of age. The safety profiles were comparable for the two different formulations. Pain/tenderness/soreness (24.8 to 28.9%) and erythema (18.4 to 21.0%) were the most commonly reported local reactions. The most common systemic adverse events (reported by ≥10% of subjects in one or more treatment groups, irrespective of causal relationship to vaccination) were: fever ≥102.0°F (38.9°C) oral equivalent (27.0 to 29.2%), upper respiratory infection (26.9 to 29.7%), otitis media (12.0 to 14.1%), cough (11.0 to 15.1%), rhinorrhea (8.7 to 10.6%), and irritability (6.5 to 11.9%). Six subjects reported serious adverse events.
Two-Dose Regimen in Children: Nine hundred eighty one (981) subjects in a clinical trial 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 cellulitis; herpes zoster^†.
^†Cases caused by wild-type varicella or vaccine strain varicella have been reported in immunocompromised or immunocompetent individuals.