Safety, reactogenicity, and immunogenicity of live attenuated varicella vaccine in children between 1 and 9 years of age with atopic dermatitis

Introduction: Infection with varicella-zoster virus (VZV) is known to facilitate secondary bacterial infection, which is cause for particular concern in children with atopic dermatitis. This 2-year study assessed the safety, reactogenicity, and immunogenicity of a live attenuated Oka strain varicella vaccine (Varilrix, GlaxoSmithKline Biologicals) in 160 children aged 1-9 years with atopic dermatitis randomized to vaccination at the start of either the 1st or 2nd study year (VAR-1Y and VAR-2Y, respectively). Mean SCORing Atopic Dermatitis (SCORAD) scores at baseline were 19.3 +/- 11.1 and 26.0 +/- 10.4 in the two groups, respectively. Results: Varicella vaccination did not adversely affect the severity of atopic dermatitis, with analysis of variance (ANOVA) confirming equivalence for the change in SCORAD index from baseline to week 8 between vaccinated and unvaccinated subjects. Within-group comparison of post-vaccination changes in SCORAD index from baseline to week 8 and month 12 in the VAR-2Y group showed a greater reduction in mean SCORAD scores following vaccination in year 2 than in year 1 when subjects were unvaccinated. Overall, SCORAD indices fell by approximately 10 points in both study groups over the 2 years of follow-up. Varicella vaccination was well tolerated, with no children withdrawn due to adverse events. Injection site redness was the most frequent solicited adverse event, occurring in 17.1% of subjects. Seroconversion rates were 94.3% at week 8 and 88.9% at month 12. In all, 43.6% of vaccinees reported at least one varicella contact during the course of the study. However, none developed varicella infection after vaccination over the 2 years of follow-up. Conclusion: In summary, vaccination with a live attenuated varicella vaccine appears safe and effective in children with atopic dermatitis.