The purpose of this study is to evaluate the safety and immunogenicity of Rotavin-M1 produced by the Center for Research and Production of Vaccines and Biologicals (POLYVAC) in infants in Vietnam. In addition, we evaluate different dosages and schedules to determine the best regimen to test in a clinical trial.

Rotavirus (RV) is the most important cause of acute gastroenteritis in children worldwide. In Vietnam rotavirus causes an estimated 122,000-140,000 hospitalizations and 2900-5400 deaths per year among children under 5 years of age (1). Over the past 13 years, sentinel hospital surveillance identified rotavirus in 44%-62% of children admitted for the treatment of acute diarrhea in Vietnam (2-4). Such a high burden of disease justified accelerated development of a new and locally manufactured vaccine against rotavirus in Vietnam. It is estimated that if a vaccine was introduced in the current childhood immunization schedule, it could reduce severe rotavirus disease by about 60% or more given current vaccine efficacies and coverage (5).

The Government of Vietnam has pursued a policy to encourage local vaccine production so the country could be self-reliant with affordable vaccines for its population (6). Over the past decades, several locally produced vaccines for poliomyelitis, cholera, Japanese encephalitis, and Diphtheria-Pertussis-Tetanus have contributed to the reduction in the prevalence of these diseases and to the eradication of polio over the past decade. While two commercial rotavirus vaccines, RotarixTM (GSK, Belgium) and RotaTeq® (Merck), have both been tested in Vietnam, neither is currently available at an affordable cost for the national program. Therefore, the candidate vaccine, Rotavin-M1, was developed in order to fill this need for a more affordable vaccine for Vietnamese children (6). This vaccine is similar to RotarixTM, and was developed by selecting a common G1P[8] strain and attenuating it through serial passages and plaque purification in qualified Vero cells under GLP conditions.

Inclusion Criteria:

• At dose 1

  1. A healthy male or female, 6 to 12 weeks of age (42 days to 84 days of age).
  2. Full term gestation (>=37 weeks).
  3. Birth weight of the subject should be >=2.5 kg.
  4. Healthy subjects as established by medical history and clinical examination before entering into the study.
  5. Did not use any dose of Rota virus vaccine.
  6. Written informed consent obtained from the parent or guardian of the subject.

• At dose 2

  1. Received dose 1.
  2. Oral informed consent obtained from the parent or guardian of the subject for continuing participate the study.

• At dose 3

  1. Received both dose 1 and dose 2.
  2. Oral informed consent obtained from the parent or guardian of the subject for continuing participate the study.

Exclusion Criteria:

• At dose 1

  1. Has a chronic disease (cardiovascular, liver, kidney disease).
  2. Acute disease at the time of enrolment.
  3. Administering corticosteroids (> 1mg/kg/day).
  4. Received any immunosuppressive therapy within 4 week before vaccination (Administration of immunoglobulins and/or any blood product or corticosteroids for >2 weeks).
  5. Immunosuppressive or immunodeficient condition.
  6. Family has immunosuppressive or immunodeficient condition medical history.
  7. History of high fever convulsion.
  8. Allergic or reaction with any component of vaccine, includes anaphylactic shock with any antibiotic.
  9. Preterm of gestation delivery (gestation period < 37 weeks).
  10. Low birth weight (<2.5 kg).
  11. Fever (axillary temperature >38oC) within 3 days before or on the day of vaccination.
  12. Malnutrition.
  13. Has any type of blood disorder, leukemia, or malignant tumor which can affect the bone marrow or lymph system.
  14. Use of any investigational or non-registered product (unlicensed 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.

• At dose 2

  1. Acute disease at the time of 2nd dose.
  2. Administering corticosteroids (> 1mg/kg/day).
  3. Received any immunosuppressive therapy within 4 week before vaccination (Administration of immunoglobulins and/or any blood product or corticosteroids for >2 weeks).
  4. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccine.
  5. Fever (axillary temperature >38oC) within 3 days before or on the day of vaccination.
  6. Has any type of blood disorder, leukemia, or malignant tumor which can affect the bone marrow or lymph system.
  7. Use of any investigational or non-registered product (unlicensed drug or vaccine) other than the study vaccine during the study period.

• At dose 3

  1. Acute disease at the time of 3rd dose.
  2. Administering corticosteroids (> 1mg/kg/day).
  3. Received any immunosuppressive therapy within 4 week before vaccination (Administration of immunoglobulins and/or any blood product or corticosteroids for >2 weeks).
  4. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccine.
  5. Fever (axillary temperature >38oC) within 3 days before or on the day of vaccination.
  6. Has any type of blood disorder, leukemia, or malignant tumor which can affect the bone marrow or lymph system.
  7. Use of any investigational or non-registered product (unlicensed drug or vaccine) other than the study vaccine during the study period.