One hundred and ninety-eight serial stool samples were collected from 27 infants and children hospitalized in Bochum, Germany with gastroenteritis due to serotype 1 rotavirus (RV). RV antigen and RV-specific antibodies (Ab) (IgA ELISA and RV Wa-neutralizing Ab) were measured. The prevalence of RV-Ab positive stool samples in RV patients did not differ from that in stool samples from 80 control patients (40% and 42% for ELISA Ab and 11% and 6% for neutralizing Ab, respectively). None of the patients was breastfed in the week preceding stool collection. No significant increase in the prevalence of RV-Ab was observed between stool samples obtained during the early and late phase of hospitalization. We observed patients that continued to excrete RV antigen in the presence of neutralizing stool activities, and patients that showed cessation of RV stool excretion and resolution of clinical symptoms in the absence of RV-neutralizing activity in the stool samples.