Samples from 96 children with acute respiratory infection were obtained simultaneously with nasal, nasopharyngeal, and oropharyngeal swabs and by nasopharyngeal aspiration and were cultured on chocolate and blood agar plates. The rates of isolation of Streptococcus pneumoniae and Haemophilus influenzae detected by the four sampling methods were compared. Nasopharyngeal aspirates were optimal for the detection of both S. pneumoniae (isolation rate, 33%) and H. influenzae (isolation rate, 31%). When a nasopharyngeal aspirate is not available, such as for healthy children or children with no obtainable secretions, the nasopharyngeal swab seems optimal for the detection of both S. pneumoniae and H. influenzae among children younger than 13 months of age. Among older children, similarly, the nasopharyngeal swab seems optimal for the detection of S. pneumoniae; however, for H. influenzae, the oropharyngeal swab seems optimal.

In a prospective nationwide laboratory-based surveillance study of all invasive bacterial and fungal infections among children < 16 years of age, 2,836 clinical cases were registered during the 5-year period 1985-1989. Of these cases, 136 were polymicrobial. During the study period, nationwide administration of Haemophilus influenzae type b conjugate vaccine reduced the incidence rates of invasive infection caused by this organism. The most common clinical diagnosis (48% of cases) was bacteremia without an identified focus of infection. The age-specific annual incidence rates of all invasive infections in children < or = 15 years of age, in children < or = 4 years of age, in children < or = 1 year of age, and in children < or = 28 days of age were 55.8, 141.4, 272.7, and 2,749.0 cases/100,000 person-years, respectively. Thirty percent of the children in the study had an underlying condition predisposing to infection. The case-fatality rate was 4.1% for all cases of invasive infection.