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

This is a dose exploration study to assess the safety and immunogenicity of two doses of the candidate HRV vaccine at different virus concentrations in the target age group (infants approximately 2 months of age and previously uninfected with human rotavirus) and receiving concomitant administration of routine vaccinations. The study also aims at exploring the effect of unrestricted feeding on the immunogenicity of the vaccine.

All subjects enrolled from Eastern United States and Eastern Canada will continue their participation in the pilot efficacy follow-up (pilot efficacy subset).

The third dose of IPV vaccine (IPOL) may be given at visit 3, 4 or another time, at the investigator's discretion.

Comvax may be given in place of OmniHIB/ActHIB at Visit 1 and Visit 2 and the third dose of Comvax administered according to the prescribing information.

Eligibility Criteria:
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.