Burden of rotavirus hospitalisations in young children in three paediatric hospitals in the United States determined by active surveillance compared to standard indirect methods.

AIM: The number of rotavirus hospitalisations is usually estimated from assigned diagnosis codes for gastroenteritis despite lack of validation for these indirect methods. Reliable estimates before and after introduction of vaccines are needed to quantify the absolute impact of new immunisation programs. METHODS: This 2-year study conducted at three hospitals prior to the licensure of the rotavirus vaccines in the USA compared two indirect methods for estimating hospitalisations for rotavirus gastroenteritis with estimates derived from prospective recruitment of children presenting with diarrhoea, vomiting or fever. For active surveillance, rotavirus gastroenteritis was confirmed by demonstration of stool antigen. The indirect residual and proportional methods assumed rotavirus to have caused a proportion of hospitalisations coded as acute gastroenteritis identified from computerised records. RESULTS: There were 447 rotavirus hospitalisations among inpatients 31 days through 4 years of age admitted with vomiting and/or diarrhoea, compared with 306 and 228 hospitalisations identified by the two indirect methods. Only 52% of children hospitalised with gastroenteritis received a qualifying diagnosis code at discharge. Relative to active surveillance, the sensitivity and specificity (95% confidence interval (CI)) in identifying rotavirus-attributable hospitalisations was 45% (95% CI: 43-48%) and 89% (88-90%) for the residual method and 34% (30-39%) and 92% (90-94%) for the proportional method. CONCLUSIONS: Many children admitted to the hospital with diarrhoea, vomiting or fever were not assigned discharge codes for acute gastroenteritis. Consequently, standard indirect methods missed a substantial number of rotavirus-associated hospitalisations, thereby underestimating the absolute number of children who could potentially benefit from vaccination.

Nonmedical costs associated with rotavirus disease requiring hospitalization.

BACKGROUND: As the most common cause of severe diarrhea among children, rotavirus has a significant economic impact. Previous studies focused on the direct medical costs of rotavirus infections; however, nonmedical costs account for the majority of the financial burden from this disease. Herein, we report the results from the largest prospective study in the United States determining the nonmedical costs of severe rotavirus infections. METHODS: Prospective, active, gastroenteritis case surveillance was conducted between November 1997 and December 1999 at 3 pediatric medical centers. Rotavirus infection was identified for 548 children admitted between 2 weeks and 5 years of age. Detailed information about nonmedical costs during the prehospitalization, hospitalization and posthospitalization periods was obtained through interviews. RESULTS: The average nonmedical cost per case of rotavirus disease was USD $448.77, including $359.04 for missed work, $56.66 for transportation, $11.90 for oral rehydration solutions, $9.59 for diapers, $6.83 for child care changes, $3.82 for special foods and $0.93 for formula changes. More than one-half of these expenses (53%) occurred outside the hospitalization period, and 80% of the cost was attributable to missed work. CONCLUSIONS: With an estimated 50,000 hospitalizations attributable to rotavirus each year in the United States, the nonmedical costs of severe rotavirus infections may exceed USD $22 million annually. Previous cost effectiveness analyses of rotavirus vaccines substantially underestimated this burden, suggesting that the nonmedical costs associated with mild to moderate rotavirus disease have been similarly underestimated. These findings are needed to assess accurately the cost effectiveness of future rotavirus immunization strategies.