The heptavalent pneumococcal conjugate vaccine immunization project by Bangkok Metropolitan in Thai infants

Streptococcus pneumoniae is the most common cause of bacteremia, sepsis, meningitis, pneumonia, sinusitis and otitis media in children worldwide. Several studies have shown that the heptavalent pneumococcal conjugate vaccine (PCV7) is highly immunogenic, safe and effective against disease caused by serotypes contained in the vaccine. To determine the safety and efficacy of PCV7 administered to Thai infants. Ninety-seven infants received four doses of PCV7. Three primary doses were given 2 months apart starting at the age of 2-6 months and the booster dose at the age of 12-15 months. Reactogenicity and safety were evaluated from parent reports. The impact of PCV7 on the occurrence of invasive pneumococcal disease (IPD) among vaccinees was examined. PCV7 was well tolerated. Two infants reported low-grade fever. None of the vaccinees developed IPD during the 1-year period following the first PCV7 dose. Primary immunization followed by a booster dose of PCV7 appeared safe and efficactive in preventing IPD in Thai children.