Intussusception is a form of bowel obstruction which occurs when one segment of the bowel becomes enfolded within another segment, which if not treated promptly, can be fatal. Treatment for intussusception includes air or hydrostatic reduction enema under X-ray SRT1720 supplier or ultrasound guidance or by surgery,

including resection of any necrosed segment of intestine. Intussusception is uncommon, and the incidence varies across regions. Incidence in most developed countries including the United States, Australia, and Hong Kong is <1 case per 1000 infants <1 year of age [19]. Data on incidence in developing countries are limited but the incidence reported from some countries, such as Vietnam, is significantly higher (>3 cases per 1000 infants <1 year of age) [19]. The reason for these observed regional differences in incidence is unknown. Compared with infants in developed countries, infants in developing countries tend to present after a longer duration of symptoms and have higher rates of intestinal resection, complications, and death [20]. Incidence of intussusception increases rapidly during the first 6 months of life and then gradually declines in older infants

[21] (Fig. 1). The etiology of intussusception in the majority of infants is not known although some infectious agents, particularly respiratory adenoviruses, selleck products have been associated with intussusception in some studies [22] and [23]. The association of natural rotavirus infection and

intussusception has not been fully explored [19] and [24]. In August 1998, a tetravalent rhesus-human reassortant rotavirus vaccine (RotaShield, Wyeth) containing G1–G4 rotavirus strains was licensed and recommended for routine immunization of US infants with 3 doses given at 2, 4, and 6 months of age; catch-up Cediranib (AZD2171) immunization with first dose was allowed until 6 months of age [25]. Some US infants developed intussusception in the first few months after RotaShield was licensed and use of this vaccine was suspended [26]. A national case–control study was then conducted and found that RotaShield vaccine increased the risk of intussusception 37 times over the expected risk during days 3–7 after the first dose and 8-fold during days 8–14 following dose 1 [2]. After dose 2, the risk of intussusception was still significantly elevated but lower than after dose 1 with a 4-fold increase over baseline during days 3–7 following dose 2. It was estimated that one additional case of intussusception would be caused among every 10,000 infants vaccinated with RotaShield vaccine [27]. After reassessing these data, some researchers suggested that the risk of intussusception was age-dependent, with increasing risk of intussusception corresponding with increasing age of administration for dose 1.