Study of Two Doses of GSK Biologicals' Live Attenuated HRV Vaccine (Two Different Formulations) in Healthy Infants.

Inclusion Criteria: * A male or female child between, and including 6 and 12 weeks (42-90 days) of age at the time of the first vaccination. * Free of obvious health problems as established by medical history and clinical examination before entering into the study. * Written informed consent obtained from the parents or guardians of the subject. * Born after a normal gestation period (between 36 and 42 weeks). Exclusion Criteria: * Use of any investigational or non-registered drug or vaccine other than the study vaccine within 30 days preceding the study vaccine or placebo or planned use during the study period. * Planned administration of a vaccine (including routine pediatric vaccines) not foreseen by the study protocol during the period starting from 14 days before each dose of vaccine(s) and ending 14 days after. Hepatitis B vaccine given concomitantly or within 14 days before and after vaccination is not an exclusion criteria. * Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs since birth. * History of diphtheria, tetanus, pertussis, polio, Hib disease and/or invasive pneumococcal infection. History of invasive pneumococcal infection is not an exclusion criteria for Canadian subjects. * Previous vaccination against diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b, and/or Streptococcus pneumoniae. Previous vaccination against Streptococcus pneumoniae is not an exclusion criteria for Canadian subjects. * Use of antibiotics within 7 days preceding dose 1. * Any clinically significant history of chronic gastrointestinal disease including any uncorrected congenital malformation of the GI tract or other serious medical condition as determined by the investigator. * Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection. * History of allergic disease or reaction likely to be exacerbated by any component of the vaccine. * Acute disease at time of enrollment. * Gastroenteritis within 7 days preceding the study vaccine administration. * Household contact with an immunosuppressed individual or pregnant women. * Administration of immunoglobulins and/or blood products since birth or planned administration during the study period. * Previous confirmed occurrence of rotavirus gastroenteritis. * Inability to contact parents/guardians of the subject by telephone.