Perinatal risk factors for infant hospitalization with viral gastroenteritis

Context. A tetravalent vaccine against rotavirus, the most commonly identified etiologic agent of viral gastroenteritis (GE), has recently been licensed for use in the United Slates. Objective. To evaluate whether specific groups of infants might be at sufficiently high risk to warrant a focused rotavirus vaccine policy, we investigated perinatal risk factors for hospitalization with viral GE and rotavirus in the first year of life. Design. Population-based, case-control study. Setting. Washington State linked birth certificate and hospital discharge abstracts from 1987 through 1995. Patients. Infants, 1 through 11 months ofage, hospitalized for viral GE (N = 1606) were patients in this study. Control subjects were 8084 nonhospitalized infants, frequency-matched to patients on year of birth. Primary Outcome Measure. Maternal and infant characteristics associated with infant hospitalization for viral CE. Results. We found a significant association between birth weight and the risk for hospitalization. Very low birth weight infants (<1500 g) were at the highest risk (odds ratio [OR] 2.6; 95% confidence interval [CI]: 1.6, 4.1);, low birth weight infants (1500-2499 g), at intermediate risk (OR 1.6; 95% CI: 1.3, 2.1); and large infants (>4000 g), at reduced risk (OR 0.8; 95% CI: 0.6, 0.9). Other characteristics associated with GE hospitalization were male gender (OR 1.4; 95% CI: 1.3,1.6); maternal smoking (OR 1.2; 95% CI: 1.1,1.4); unmarried mother (OR 1.2; 95% CI: 1.1,1.4); Medicaid insurance (OR 1.4; 95% CI: 1.3, 1.7); and maternal age <20 years (OR 1.2; 95% CI: 1.0, 1.5). Infants born October through December were at decreased risk for hospitalization (OR 0.8; 95% CI: 0.7,0.9), as were infants born to Asian mothers (OR 0.5; 95% CI: 0.3, 0.7), and infants born to mothers >34 years of age (OR 0.7; 95% CI: 0.6,0.9). Using these factors, the area under a receiver operating characteristic curve was 0.63. Therefore, to achieve a sensitivity of 90% in identifying highrisk infants, specificity would fall to 10%. Subanalyses of children admitted for viral GE during the peak of the Northwest rotavirus season (January to March) and children with confirmed rotavirus infection demonstrated similar risk factors and receiver operating characteristic curves. Conclusion. We conclude that a focused rotavirus vaccination policy using readily identifiable potential highrisk groups would be unlikely to prevent most infant hospitalizations associated with rotavirus infection. However, the safety of rotavirus vaccine in low birth weight and premature infants must be established, because these children appear to be at greater risk for hospitalization with viral GE and rotavirus.