The Immunogenicity of Rotavirus Vaccine Under Different Age Schedules and the Impact of Withholding Breast Feeding Around the Time of Vaccination on the Immunogenicity of Rotarix Vaccine

Rotavirus is one of the most common causes of severe diarrhea, responsible for 40% of all diarrhea related deaths in children worldwide. Two vaccines against Rotavirus, Rotarix® and Rotateq® were licensed in many high and middle income countries in 2006, but lack of efficacy data in low income countries had prevented WHO from making a universal recommendation of their use until recently. This study will be conducted in Pakistan and will look at two objectives:

1. To compare the immunogenicity of Rotarix® vaccine when administered at 6 and 10 weeks of life and at 6, 10 and 14 weeks of life.
2. To compare the immunogenicity of Rotarix® vaccine in infants breast fed at the time of vaccine administration with infants whose breast feeding is withheld for one hour before and after vaccine administration.