The Effectiveness of Varicella Vaccine in Daycare Center Children

Aim: We aim to show effectiveness of varicella vaccine in prevention of severe disease in day-care center children. Material and Method: Study group was consisted of 144 day-care center children. Of them 73 (50.6%) were immunized against varicella before. Mean age was 38 +/- 34 months (6 to 72 months) and 65 of them (41.6%) diagnosed as varicella. Severity of disease was classified as mild, and moderate-severe disease as some clinical parameters. Mild disease as defined as fever less than 3 days, number of vesicular lesions was under 50. Severe disease defined as lesions above 50 and longer duration of fever and seen of any complication. Effectiveness of varicella vaccine was estimated a formulary, VE: % (AUC-AVD)/AUCx100. Results: Varicella was seen in 6 of immunized (8.2%) and 59 of unimmunized children (83%). Severe disease was seen 33.8% of unimmunized children, and none of them was in immunized group. The effectiveness of vaccine estimated as 90.1% (odds ratio 14.1; 95% CI 2.4-80.9). Varicella vaccine was more effective if it done at 15th month or older age than at 12th month. Conclusion: Varicella vaccine is highly effective for prevention of severe disease in day-care center children.