An open label study to evaluate immunogenicity, safety, and reactogenicity of Rotavac® (live attenuated oral rotavirus vaccine) as a 3-dose series in healthy infants aged between 6 weeks and 8 weeks in Vietnam.

Inclusion Criteria:

• Healthy infants as established by medical history and clinical examination before entering the study.
• Age: 6-8 weeks
• Weight ≥ 2.5kg at birth.
• Infants received EPI vaccines at birth (i.e., OPV, BCG and/or Hep B)
• Parental ability and willingness to provide informed consent.
• Parent who intends to remain in the area with the participant during the study period.

Exclusion Criteria:

• Presence of diarrhea or vomiting in the previous 72 hours or on the day of enrollment (temporary exclusion).
• Presence of fever (temperature ≥37.5oC) or hypothermia (temperature ≤35.5oC) on the day of enrollment (temporary exclusion).
• Concurrent participation in another clinical trial.
• Presence of significant malnutrition or any systemic disorder (cardiovascular, pulmonary, hepatic, renal, gastrointestinal, hematological, endocrine, immunological, dermatological, neurological, cancer or autoimmune disease) as determined by medical history and/or physical examination which would compromise the infant's health or is likely to result in non-conformance to the protocol.
• History of congenital abdominal disorders, intussusception, abdominal surgery
• Known or suspected impairment of immunological function based on medical history and physical examination.
• Prior receipt of rotavirus vaccine.
• A known sensitivity or allergy to any components of the study medication.
• Major congenital or genetic defect.
• Participant's parents not able, available or willing to accept active follow-up by the study staff.
• Has received any immunoglobulin therapy and/or blood products since birth or planned administration during the study period.
• History of chronic administration (defined as more than 14 days) of immunosuppressants including corticosteroids. Infants on inhaled or topical steroids may be permitted to participate in the study.
• History of any neurologic disorders or seizures.
• Any medical condition in the parents/infants that, in the judgment of the investigator, would interfere with or serves as a contraindication to protocol adherence or a participant's parent's/legally acceptable representative's ability to give informed consent.

An open label study to evaluate immunogenicity, safety, and reactogenicity of Rotavac® (live attenuated rotavirus vaccine) as a 3-dose series in healthy infants aged between 6 weeks and 8 weeks in Vietnam