Burden of invasive bacterial disease among children younger than 5 years of age in Togo

Abstract

Background: Haemophilus influenzae b (Hib), pneumococcus and meningococcus are responsible for high mortality and morbidity in children younger than 5 years of age worldwide. Hib containing vaccine was introduced in July 2008 in Togo; and baseline data are available on bacterial meningitis prior to PCV13 vaccine starting June 2014. We reported the burden of invasive bacterial disease (IBD) seven years after Hib vaccine introduction.

Method: From 2010-2015 we conducted sentinel surveillance for pediatric bacterial meningitis in Sylvanus Olympio Teaching Hospital in Lome among children younger than 5 years of age, implementing the WHO’s generic protocol. Focusing on meningitis, the diagnosis was confirmed on cerebrospinal fluid by culture, latex agglutination, immunochromatographic or PCR. We received technical assistance from The Gambian regional reference laboratory for PCR processing. Invasive bacterial disease was compared to severe malaria enrolled as suspected meningitis.

Results: From 2010 to 2015, 3386 children younger than 5 years of age were enrolled with suspected meningitis; and 39% of them had received at least one antibiotic prior to the admission. Invasive bacterial disease represented 30% of enrolled cases. The case fatality rate among children with suspected meningitis was 11%; with 18% for invasive bacterial disease versus 9% for severe malaria. The specific case fatality rate was 18% (72/394) for meningitis, 13% (21/155) for pneumonia and 47% (8/17) for sepsis. Probable bacterial meningitis was observed in 5% of cases; with confirmed meningitis in 39% of them. Pneumococcal meningitis represented 65% of confirmed meningitis cases; 32% for Haemophilus influenzae (Hi); and 3% for meningococcus. The specific case fatality rate for pneumococcal meningitis was 27% and 18% for Hi. Pneumococcus strain was not typable in 41% of cases; and 79% of Hi strains were non-type b.

Conclusions: Surveillance for meningitis has highlighted the magnitude of pneumococcal meningitis in Togolese children. It would be helpful to continue the surveillance for showing the impact of conjugated vaccines on invasive bacterial disease.

Keywords: Pneumococcus, Haemophilus influenzae, meningitis, children, Togo