What adverse events are associated with varicella vaccine?
Varicella vaccine is very safe. Although vaccine recipients in uncontrolled trials reported minor injection site complaints (20% reported pain, swelling or redness) and rashes (3%-5% reported a localized rash, and an additional 3%-5% developed a generalized varicella-like rash 5-26 days after vaccination), the rate of adverse events was much lower in the only randomized, controlled clinical trial conducted in children. In this trial 1% of vaccine recipients developed injection site rash compared with 0.3% of placebo recipients and 3.2% of vaccine recipients developed generalized rash compared with 1.7% of placebo recipients. These rashes had an average of 2-5 lesions and were likely to be maculopapular rather than vesicular. The incidence of fever did not differ between the vaccination and placebo groups. Experience with the first 11 million doses distributed show that very infrequently (in approximately 2.8 per 100,000 doses given) serious adverse events such as seizures, encephalitis
