Haemophilus influenzae type b invasive infections in children hospitalized between 2000 and 2017 in a Pediatric Reference Hospital (PRH).

Abstract

BackgroundUruguay incorporated the conjugate vaccine against Haemophilus influenzae b (Hib) in 1994. In 2008, the vaccine was changed from one with natural conjugated capsular polysaccharide to one with a synthetic polysaccharide component. We describe the frequency and characteristics of invasive Hib infections in children hospitalized in a Pediatric Reference Hospital (PRH) between January 1st, 2000 and December 31st, 2017.MethodsSterile site Hib isolations from hospitalized children were included. Clinical and microbiological characteristics were analyzed. Favorable conditions for the infection were considered: incomplete immunization, immunodeficiencies and associated pathologies. Two periods are described: 1, prior to vaccine change (1/1 st/2000- 12/31/08) and 2, post-change (1/1 st/09- 12/31st/17).Results45 children were hospitalized: 5 in the first period and 40 in the second. The hospitalization rate per 10,000 discharges was 0.41 (95% CI 0.05–0.77) and 4.2/10,000 (95% CI 2.89–5.48), respectively (p < 0.01). The diagnoses at discharge were: meningitis/ventriculitis (20), pneumonia (16), bacteremia (3), epiglottitis (1), arthritis (1), cellulitis (3) and obstruction of the upper airway (1). Four children presented comorbidities. Twenty seven received less than 3 doses of anti-Hib vaccination and 18 were properly vaccinated (2 were immunodeficient). The median hospitalization was 14 days, 18 children required intensive therapy.ConclusionsObserved change may be due to: incomplete primary series, inhomogeneous vaccine coverage and immunogenicity of the synthetic polysaccharide. To reduce this public health problem, epidemiological surveillance.