Perinatal risk factors for infant hospitalization with viral gastroenteritis

Context. A tetravalent vaccine against rotavirus, the most commonly identif ied etiologic agent of viral gastroenteritis (GE), has recently been licens ed for use in the United Slates. Objective. To evaluate whether specific groups of infants might be at suffi ciently high risk to warrant a focused rotavirus vaccine policy, we investi gated perinatal risk factors for hospitalization with viral GE and rotaviru s in the first year of life. Design. Population-based, case-control study. Setting. Washington State linked birth certificate and hospital discharge a bstracts 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 nonhospital ized infants, frequency-matched to patients on year of birth. Primary Outcome Measure. Maternal and infant characteristics associated wit h infant hospitalization for viral CE. Results. We found a significant association between birth weight and the ri sk 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 wer e 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 (O R 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 hosp italization (OR 0.8; 95% CI: 0.7,0.9), as were infants born to Asian mother s (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 o perating characteristic curve was 0.63. Therefore, to achieve a sensitivity of 90% in identifying highrisk infants, specificity would fall to 10%. Sub analyses 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 characte ristic curves. Conclusion. We conclude that a focused rotavirus vaccination policy using r eadily 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 m ust be established, because these children appear to be at greater risk for hospitalization with viral GE and rotavirus.