Potential Mechanisms for Intussusception After Rotavirus Vaccine-Pilot Study

This is a prospective randomized clinical trial that aims to evaluate the potential effects of the first dose of rotavirus vaccines on gastrointestinal motility and anatomy and blood and stool cytokine responses. It will also assess the association between these outcomes and the pattern of the shedding of vaccine strain rotavirus in the stool. Infants will be randomized to one of four arms: monovalent rotavirus vaccine (Rotarix®, RV1) alone, RV1 with other recommended vaccines, pentavalent rotavirus vaccine (RotaTeq®, RV5) alone, or RV5 with other recommended vaccines. Data derived from the pilot study will be used to assess the feasibility of conducting a larger scale study.

Healthy infants 6-13 weeks of age will be randomized (1:1:1:1) to receive either, RV1 alone, RV1 with Advisory Committee on Immunization Practices (ACIP) routinely recommended immunizations (Diphtheria, Tetanus and Pertussis (DTaP), Haemophilus influenza type b (Hib), pneumococcal conjugate (PCV13), Hepatitis B (HBV) and inactivated polio (IPV)), RV5 alone or RV5 with ACIP routinely recommended immunizations. Imaging study personnel and parents will be blinded to the rotavirus vaccine type; parents will be informed about the rotavirus vaccine type at the completion of the study. Up to 100 infants will be enrolled. Recruitment and enrollment will occur prior to the first clinic visit. There will be four study visits including the recruitment/enrollment visit and three clinic visits. Infants will be randomized to either RV1, RV1 plus other immunizations, RV5 alone, or RV5 plus other immunizations. Clinic Visit 1 (day 0) will include blood, saliva, stool and breast milk collection . The MRI and ultrasound will be performed prior to vaccination. Children will receive the immunizations to which they are randomized. Imaging personnel and parents will be blinded to rotavirus vaccine type; they will be informed about other vaccines administered. A second MRI and ultrasound will be performed at Clinic Visit 2 (day 5) and blood and stool samples collected. Parents will be unblinded at the completion of Clinic Visit 3 (day 14). Arrangements will be made to get remaining doses of same rotavirus vaccine. Daily stool samples will be collected at home during the 15 day study period (on vaccination day 0 and for next 14 days). A memory aid will be completed to collect reactogenicity data on days 0 and for the next 14 days. Remaining stools and reactogenicity data from parents will be collected at Visit 3. The investigators will assess blood and stool cytokine responses and intestinal anatomy and motility after rotavirus vaccination by comparing pre-vaccination with post-vaccination responses in the study infants. Cytokines and intestinal anatomy and motility will be assessed at baseline (Visit 1, the day of vaccine receipt) and 5 days after vaccination (Visit 2). For both blood and stool, the following cytokines will be tested: IL-2, IL-6, IL-7, IL-8, IL-15, INF-γ and TNF-α. Additional biomarkers may be studied.