No evidence for an unmasking effect At the ACIP meeting, the question was raised as to whether this association might be an unmasking of intussusception that was destined to happen in predisposed infants. The investigators concluded that there is a true causal association between rotavirus vaccine and intussusception. The pathogenesis of intussusception following rotavirus vaccine is not fully understood. Limited data from a few surgical specimens indicate lymphoid hyperplasia in the lamina propria of the distal small intestine. Presumably, local infection with the vaccine virus resulted in an inflammatory response and physical changes that predisposed to the inversion of the intestine.
Further studies are in progress.
Undoubtedly, this experience will slow the development of alternative vaccines. For the immediate future, interventions to minimize morbidity and mortality should include encouragement of breastfeeding and early use of oral rehydration solution to prevent the severe consequences of rotavirus infections. Rennels MB, Glass RI, Dennehy PH, et al. Safety and immunogenicity of live, attenuated human rotavirus vaccine 89-12. Epidemiology of rotavirus in infants and protection against symptomatic illness afforded by primary infection and vaccination.