Impact of Haemophilus influenza immunization on hospitalized acute respiratory infections

Abstract Background Immunization is the most cost-effective measure to combat communicable diseases in childhood. Haemophilus influenza (Hib) vaccine was included in the Tunisian expanded program of immunization for the first time in 2002 (Hib Vaccine monovalent) and is currently combined with the pneumococcal vaccine(Hib vaccine pentavalent combination) since April 2019. We aimed to assess impact of Hib vaccine on Respiratory Infection(RI) admissions in children aged up to 3 years. Methods It was a cohort study from January 1, 2002 to December 31, 2013. All Respiratory Infection (RI) admissions in children aged up to 3 years in the university hospital of Monastir(Tunisia) were enrolled. Results Admissions for RI represented 17.6% (CI95%: 17.3-18.1) of all communicable diseases hospitalizations (n = 6 061/34 289). The median age was 22 years (IQR: 3-52). Admission for Pneumonia with Streptococcus Pneumoniae (SP) increased significantly during study period (b = 25.9 (p < 0.0001)) especially in children up to 5 years old (b = 10.6) and in elderly (b = 6.0). Among children up to 3 years old, the Crude incidence rate per 100,000 for Hib pneumonia admission were 11.6 in Non-Vaccinated Cohort (NVC), 10.6 in Vaccinated Cohort (VC) by protocol 1 (Hib Vaccine monovalent) and 0.80 in VC by protocol 2 (Hib vaccine pentavalent combination).The relative risk reduction was 99% for protocol 2 (p < 0.001). Conclusions Admissions for RI in a tertiary level hospital were common with an increasing trend. The Hib immunization program, in particular the second protocol (pentavalent combination), has had a positive impact on the reduction of related acute diseases. Key messages The Hib immunization program, has had a positive impact on the reduction of related acute diseases. The “Hib vaccine pentavalent combination “is more efficient than “Hib Vaccine monovalent”.