Incidence of febrile seizures and associated factors in children in Soweto, South Africa.

ABSTRACT

BACKGROUND: Febrile seizures (FSs) are a common cause of paediatric emergencies, but there is limited research on the aetiology and epidemiology of FSs, especially in Africa. OBJECTIVES: To determine the incidence of FS hospitalisations in children aged 6 - 59 months in Soweto, South Africa, and factors associated with FS hospitalisations. METHOD: In a secondary data analysis using a cohort of children enrolled in a 9-valent pneumococcal conjugate vaccine efficacy trial conducted in Soweto during 1998 - 2005, the incidence of FS hospitalisation was calculated and stratified by age group. Regression analysis was used to investigate factors associated with FS at the time of hospitalisation. Influenza A, influenza B, respiratory syncytial virus (RSV), adenovirus and parainfluenza were investigated for among those with respiratory symptoms using immunofluorescent assays. RESULTS: FSs accounted for 780 (11.0%) of 7 126 hospitalisations during the study period. The overall incidence of FSs was 4.4 (95% confidence interval (CI) 4.10 - 4.97) per 1 000 person-years, with the highest incidence in children aged 12 - 23 months (7.25; 95% CI 6.44 - 8.14). Among hospitalised children, FS hospitalisation was associated with HIV-negative status (odds ratio (OR) 6.25; 95% CI 4.34 - 8.99), body temperature ≥39ºC (OR 2.03; 95% CI 1.56 - 2.64) and concurrent diagnosis of acute otitis media (OR 2.16; 95% CI 1.74 - 2.67). Influenza A was identified in 44/515 FS hospitalisations (8.5%) compared with 123/3 794 non-FS hospitalisations (3.2%) (OR 2.22; 95% CI 1.56 - 3.16). In contrast, RSV detection was less commonly identified in children with FSs (21; 4.1%) than without (419; 11.0%) (OR 0.36; 95% CI 0.24 - 0.54). CONCLUSIONS: FSs contributed significantly to the burden of paediatric hospitalisations in Soweto, and were strongly associated with influenza A virus infection.