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

Abstract
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. 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 Varicella vaccination was well tolerated, with no children withdrawn due to adverse events.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. In summary, vaccination with a live attenuated varicella vaccine appears safe and effective in children with atopic dermatitis.