A dose escalating study with 3 different dosing regimens of the studied vaccine (IPOVAC- POLYVAC-Vietnam) and a licensed vaccine (IMOVAC-Sanofi Pasteur- France) is conducted in Vietnamese children, aged 2 months and above to assess the safety and immunogenicity. Two hundred and forty children are enrolled and placed randomly into 4 groups (60 children/group), each of which receive 3 doses of vaccine subcutaneously, at 4 week interval. Safety issues included immediate reaction at the site of injection and systemic reaction within 30 min of administration, within 7 days after each dose, unexpected event occur within 30 days of each dose, SAE (from start of dose 1 to 30 days after dose 3), blood cell count, urea, ALT,AST. Immunogenicity outcomes include seroconversion of neutralising antibodies for each of vaccine serotypes.

The use of oral poliomyelitis vaccine (OPV) in Vietnam expanded immunisation program has resulted in successful eradication of polio in Vietnam. However due to the concern of OPV-related poliomyelitis cases occurred worldwide, WHO has recommended the countries to gradually change to inactivated polio vaccine (IPV). In Vietnam, POLYVAC has been approved and sponsored by the Ministry of Science and Technology to produce IPV under Japanese technology. The vaccine consisting of 3 serotypes (Serotype 1,2 and 3) has been proven safety in volunteer adults.

In this study, a dose escalating study with 3 different dosing regimens of the studied vaccine (IPOVAC) and a licensed vaccine (IMOVAC-Sanofi Pasteur- France) is conducted in Vietnamese children, aged 2 months and above to assess the safety and immunogenicity. Two hundred and forty children are enrolled and placed randomly into 4 groups (60 children/group), each of which receive 3 doses of vaccine subcutaneously, at 4 week interval. Safety issues evaluated include immediate reaction at the site of injection and systemic reaction within 30 min of administration, within 7 days after each dose, unexpected event occur within 30 days of each dose, SAE (from start of dose 1 to 30 days after dose 3), blood cell count, urea, ALT,AST. Seroconversion rates of neutralising antibodies for each of vaccine serotypes are to be assessed.

Inclusion Criteria:

• Children of both sexes, 2 months of ages
• Full term babies (>=37 weeks)
• Weight at birth (>=2500gr)
• Have not been vaccinated with polio vaccine or vaccine containing poliovirus components
• Not currently have acute infection (assessed via clinical check up and asking parents/care givers about health history before enrolment
• Parents/legal guardians agree to participate their children in this study and sign the informed consent.

Exclusion Criteria:

• Currently have chronic diseases (cardiovascular, liver and spleen related etc)
• Use (orally or through infection) with corticoid containing drug (>1mg/kg dose)
• Use of immunocompromised treatment within 4 weeks of enrolment
• Being immunocompromised and autoimmune diseases (HIV, lupus)
• the history of immunocompromised in the family
• history of high fever
• Allergic for any vaccine component
• Fever (>38oC) within 3 days before vaccination or at enrolment
• Malnourished (3rd level or above)
• Blood disorder
• use of vaccines which have not been licences 7 days before enrolment in this study

Individual data with identification removed are to be available for Ethical committee, Ministry of Health and National Foundation of Science and Technology Development to avoid misuse of data.

Public shared data will be in the form of summarised tables and figures.