The Impact of Haemophilus Influenzae and Streptococcus Pneumoniae Vaccination in Bacterial Meningitis in a Pediatric Referral Hospital in Mexico

Objective The study aimed to compare the epidemiology of bacterial meningitis (BM) before and after vaccination, and identify possible risk factors associated with mortality. Methods The medical and microbiologic records of children (1 month-18 years) with a discharge diagnosis of BM in a third level children's hospital in Mexico from 1990 to 2018 were reviewed. The epidemiology, pathogens, and outcomes were compared before and after introducing Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines to the Mexican immunization schedule. Risk factors associated with mortality were determined. Results In the 28-year period, 226 cases with BM were included 55.8% (1990-1999), 27.4% (2000-2008), and 16.8% (2009-2018) (p=0.0001). The most frequent pathogen was Hib, documented in 39% of cases. There was a reduction in neurological complications after introducing the Hib conjugate vaccine (59 vs. 39%; p=0.003) and sequelae after the Streptococcus pneumoniae conjugate vaccine (43 vs. 35%; p=0.05). Independent risk factors associated with mortality were coma (odds ratio [OR]: 15 [2.9-78]), intracerebral bleeding (OR: 3.5 [1.4-12]), and pneumococcal meningitis (OR: 9.4 [2.2-39]). Conclusion Since the introduction of Hib and pneumococcal conjugate vaccines to the national immunization schedule, there was a reduction in BM cases, mainly associated with the Hib vaccine, with the consequent reduction of neurological complications and sequelae.