Clinical and epidemiological impact of varicella infection in children prior to the introduction of the varicella vaccine in the national immunization schedule of Argentina

Abstract

Introduction. In Argentina, an estimated 400 000 varicella cases occur annually. Given the under-recording of existing cases, the actual burden of disease is unknown. Objective.Toassesstheburdenofvaricellabefore the introduction of the varicella vaccine in the national immunization schedule. Materialsandmethods.Retrospective,analytical, observational study carried out in three hospitals of Argentina. Review of medical records from outpatient visits to the Emergency Department and from patients younger than 18 years hospitalizedforvaricella.Period:1/2011-12/2013.Results. A total of 382 782 outpatients were seen; 3367(0.88%)correspondedtovisitsduetovaricella; 57.6 % were ≤ 4 years old. A total of 164 (4.9 %) patientsrequiredhospitalization,withanoverall hospitalization rate of 65.3/10 000 hospitalized patients/year (95 % confidence interval [CI]: 55.4-76.5); hospitalization rate in healthy children: 57.2/10 000 (95 % CI: 67.7-48.0); median age: 31.5 months. The most common causes of hospitalization were skin and/or soft tissue infections (61.1 %) and respiratory infections (10.1 %). Also, 54.3 % were treated with acyclovir and 73.1 %, with antibiotics. Bacteremia developed in 5/67 patients (7.5 %), all cases were caused by Gram-positive cocci and occurred in immunocompetent patients. Out of 19 immunocompromised patients, 36.8 % had complications (5 skin and/or soft tissue infection and 2 pneumonia cases). The median length of stay was 4 days, which is significantly more prolonged in immunocompromised patients. One patient required intensive care. No patient died. Conclusion. The burden of disease was significant,withaconsiderableimpactinpatients without an underlying disease.