Risk of Haemophilus influenzae type b meningitis in Polish children varies directly with number of siblings: possible implications for vaccination strategies.

Background: In the absence of an effective vaccine, Haemophilus influenzae type b (Hib) meningitis has frequently been found to be the most common bacterial meningitis among children less than or equal to 5 years of age. This study was conducted prior to the introduction of Hib vaccine in Poland, and is the first case-control study of Hib meningitis in this country.

Methods: A 1:3 matched case-control study was nested within a population-based surveillance study of Hib meningitis in children less than or equal to 5 years old in Poland.