• Serum anti-rotavirus IgA antibody concentration in a subset of subjects. [ Time Frame: One month after the second dose of HRV vaccine/Placebo. ] [ Designated as safety issue: No ]
• Occurrence of any RV GE and severe RV GE leading to medical intervention and caused by the circulating wild-type RV strains of G1 serotype [ Time Frame: During the efficacy follow-up period. ] [ Designated as safety issue: No ]
• Occurrence of any RV GE and severe RV GE leading to medical intervention and caused by the circulating wild-type RV strains of non-G1 serotypes. [ Time Frame: During the efficacy follow-up period. ] [ Designated as safety issue: No ]
• Occurrence of hospitalisation due to RV GE caused by the circulating wild-type RV strains [ Time Frame: During the efficacy follow-up period. ] [ Designated as safety issue: No ]
• Occurrence of any RV GE and severe RV GE leading to medical intervention and caused by the circulating wild-type RV strains (G1 and non-G1 RV types). [ Time Frame: During the period starting from Dose 1 up to Visit 5. ] [ Designated as safety issue: No ]
• Occurrence of each type of solicited symptom [ Time Frame: Within the 8-day solicited follow-up period after each dose of HRV vaccine/Placebo. ] [ Designated as safety issue: No ]
• Occurrence of unsolicited adverse events according to Medical Dictionary for Regulatory Activities (MedDRA) classification. [ Time Frame: Within 31 days after any dose of HRV vaccine/Placebo. ] [ Designated as safety issue: No ]
• Occurrence of severe RV GE leading to a medical intervention and caused by the circulating wild-type RV strains. [ Time Frame: During the efficacy follow-up period. ] [ Designated as safety issue: No ]
• Occurrence of serious adverse events. [ Time Frame: Throughout the study period. ] [ Designated as safety issue: No ]
• Seroconversion in terms of anti-rotavirus IgA antibody in a subset of subjects. [ Time Frame: One month after the second dose of HRV vaccine/Placebo. ] [ Designated as safety issue: No ]

This study is undertaken to provide the regulatory authorities in Japan with immunogenicity, efficacy, safety and reactogenicity data of GSK Biologicals' HRV vaccine, given as a 2-dose primary vaccination, in healthy Japanese infants aged approximately 2 months at the time of the first dose and previously uninfected with HRV. The Protocol Posting has been updated in order to comply with the FDA Amendment Act, Sep 2007.

DTPa and HBV vaccines are allowed to be co-administered along with Rotarix vaccine/Placebo.

• Biological: Placebo
• Biological: Rotarix

Inclusion Criteria:

• Healthy male or female infant between, and including, 6 and 14 weeks (42-104 days) of age at the time of the first vaccination.
• Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol should be enrolled in the study
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• Written informed consent obtained from the parent or guardian of the subject.
• Born between a gestation period of 36 and 42 weeks inclusive.

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) other than the HRV vaccine within 30 days preceding the first dose of HRV vaccine, or planned use during the study period.
• History of use of experimental rotavirus vaccine.
• Chronic administration of immunosuppressants or other immune-modifying drugs since birth.
• Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product (pharmaceutical product or device).
• Uncorrected congenital malformation (such as Meckel's diverticulum) of the gastrointestinal tract that would predispose for intussusception.
• Any clinically significant history of chronic gastrointestinal disease including any uncorrected congenital malformation of the gastrointestinal tract or other serious medical condition determined by the investigator.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• Previous confirmed occurrence of RV GE.
• Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination (no laboratory testing is required).
• A family history of congenital or hereditary immunodeficiency.
• Acute disease at the time of enrolment.
• Gastroenteritis within 7 days preceding the study vaccine administration.
• Administration of immunoglobulins and/or any blood products since birth or planned administration during the study period.