Rotavirus (RV) is the most important cause of acute gastroenteritis (GE) requiring the hospitalization of infants and young children in developed and developing countries and can be a frequent cause of death in children less than 5 years of age (estimated nearly 500,000 annual deaths worldwide). GlaxoSmithKline (GSK) Biologicals has developed a vaccine against human rotavirus gastroenteritis. A new formulation of the vaccine, with an alternative buffer, was developed. This study will be conducted to evaluate the new formulation compared to the existing formulation of the HRV vaccine.

The study consists of four groups of children recruited in different centers in Finland. One group of children will receive the existing formulation of HRV vaccine and one group will receive the new formulation of the HRV vaccine. The other two groups will receive the placebo for existing formulation or the new formulation based on the allocation. The vaccine or placebo will be administered starting at 6 - 12 weeks of age according to 0, 1 month schedule. Routine childhood vaccinations are allowed according to local practice, but at least 14 days apart from each dose of study vaccine. The duration of the study will be approximately 2 months per child.

Inclusion Criteria:

• Subjects with parents/guardians who the investigator believes can and will comply with the requirements of the protocol should be enrolled in the study.
• Males or females between, and including, 6 and 12 weeks (42 - 90 days) of age at the time of the first vaccination.
• Written informed consent obtained from the parents or guardians of the subjects.
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• Born after a gestation period of 36 to 42 weeks inclusive.

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine within 30 days preceding the first dose of study vaccine, or planned use during the study period.
• Planned administration of a vaccine (including routine paediatric vaccines) not foreseen by the study protocol during the period starting from 14 days before each dose of study vaccine(s) and ending 14 days after.
• 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)
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs since birth. (For corticosteroids, this will mean prednisone, or equivalent, 0.5 mg/kg/day. Inhaled and topical steroids are allowed.)
• Any clinically significant history of chronic gastrointestinal disease including any uncorrected congenital malformation of the gastrointestinal tract or other serious medical condition, as determined by the investigator.
• History of allergic diseases or reactions likely to be exacerbated by any component of the vaccine.
• Any confirmed or suspected immunosuppressive or immunodeficient condition based on medical history and physical examination (no laboratory testing is required).
• Major congenital defects or serious chronic illnesses.
• Acute disease at time of enrolment. (Acute disease is defined as the presence of moderate or severe illness with or without fever, i.e. temperature >= 37.5°C as measured by an axillary thermometer or >= 38.0°C as measured by a rectal thermometer.) Temperature greater than or equal to these cut-offs warrants deferral of the vaccination pending recovery of the subject.
• Gastroenteritis (GE) within 7 days preceding the study vaccine administration (warrants deferral of the vaccination).
• Household contact with an immunosuppressed individual or pregnant woman.
• Administration of immunoglobulins and/or blood products since birth or planned administration during the study period.
• Previous confirmed occurrence of RV GE.
• History of neurological disorders or seizures.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.