Trial of Simplified Pneumococcal Vaccination in Vietnam II

This is a single-blind, open-label, randomised controlled trial with five groups. There are four different PCV schedules to be evaluated: a 0+1 schedule of PCV10 at 12 months of age (Group V), a 0+1 schedule of PCV13 at 12 months of age (Group W), a 1+1 schedule of PCV10 at 2 and 12 months of age (Group X), and a 1+1 schedule of PCV13 at 2 and 12 months of age (Group Y); along with a control group that receives a dose of PCV10 at 24 months of age (Group Z). Additionally, all participants will receive four doses of Infanrix-hexa at 2, 3, 4 and 18 months of age.

Inclusion criteria

• Aged between 2 months and 2 months plus 2 weeks;
• No significant maternal or perinatal history;
• Born at or after 36 weeks gestation;
• Written and signed informed consent from parent/legal guardian;
• Lives within approximately 30 minutes of the commune health centre;
• Family anticipates living in the study area for the next 22 months

Exclusion criteria

• Known allergy to any component of the vaccine;
• Allergic reaction or anaphylactic reaction to any previous vaccine;
• Known immunodeficiency disorder;
• Known HIV-infected mother;
• Known thrombocytopenia or coagulation disorder;
• Administration or planned administration of any immunoglobulin or blood product since birth;
• Severe birth defect requiring ongoing medical care;
• Chronic or progressive disease;
• Seizure disorder;
• History of severe illness;
• Receipt of any 2 month vaccines through the Expanded Programme of Immunization (EPI) program;
• Family plans on giving the infant Quinvaxem (DTP-Hib-HBV).

Additionally, enrolment will be deferred and infants asked to return to the health centre one week later for reassessment if they have at least one of the following deferral criteria:

• Axillary temperature ≥37.5°C or ≤35.5°C;
• Acute infection, especially bacterial;
• Oral administration of corticoid therapy in past 14 days; or
• Any of the following symptoms that interfere with normal activities: crying more than usual, sleeping more than usual, or loss of appetite.