Pneumococcal Bacteremia in Febrile Infants Presenting to the Emergency Department Before and After the Introduction of the Heptavalent Pneumococcal Vaccine

Study objective

Fever is among the most common presenting complaints of infants and children younger than 3 years who present to the emergency department (ED). The evaluation and management of the febrile child is evolving rapidly. We compare the proportion of pneumococcal bacteremia between febrile infants and children younger than 3 years who had and had not received the heptavalent pneumococcal vaccine and who had received blood culture tests in our ED.

Methods

We performed a nonconcurrent prospective observational cohort study, with a standardized medical record review to collect data of patients treated in the ED of a tertiary care military hospital during 24 months. Patients were eligible if they were younger than 36 months and had a temperature greater than or equal to 100.4°F (38°C). A data collection sheet was used to abstract age, temperature, and whether CBC count and blood cultures were obtained. Heptavalent pneumococcal vaccine status and blood culture results were obtained through review of the computerized medical record. Descriptive analysis was used for comparing the 2 groups. Group size analysis was based on the prevalence of occult bacteremia caused by Pneumococcus before the introduction of heptavalent pneumococcal vaccine. Interobserver variation was assessed by independent review of 10% of abstracted records. The main outcome measure was the proportion of positive pneumococcal blood cultures in infants and children younger than 3 years who had received at least 1 vaccination of heptavalent pneumococcal vaccine versus those who had not.

Results

Three thousand five hundred seventy-one patients met entry criteria; 1,428 had blood cultures obtained, and 833 of them received at least 1 immunization of heptavalent pneumococcal vaccine. All groups were similar in age, sex, and temperature. Positive blood culture results, including probable contaminants, were obtained for 4.2% (58/1,383) of the patients. In the heptavalent pneumococcal vaccine group, there were 0 of 833 (0%) positive pneumococcal blood cultures compared with 13 of 550 (2.4%) in the unimmunized group (P<.001; 95% confidence interval 1.4% to 3.3%).

Conclusion

Pneumococcal bacteremia was found to be lower in our patients who had received the heptavalent pneumococcal vaccine than in the patients who had not.