Preventable invasive pneumococcal disease (IPD) including meningitis, pneumonia and septicemia contributes significantly to morbidity and mortality in all age groups, particularly in children. WHO has estimated that nearly 1.6 million deaths occur globally every year due to pneumococcal disease? Almost one million of these deaths occur in children below five years of age. Pneumonia continues to be number one cause of childhood mortality in developing countries and India is no exception to it.

There are 90+ known serotypes of S.pneumoniae (variable with age and geographical distribution) but 10 most common serotypes cause almost 60% of IPD worldwide.

Conjugate vaccines have been developed which are immunogenic in infants and provide high level of protection against IPD. The PVC-7 has been shown to cover more than 80% of childhood invasive pneumococcal isolates in developed countries. In India, the Invasive Bacteria Infection Surveillance (IBIS) study showed that PCV-7 would cover approximately 47% IPD serotypes prevalent in this country. WHO recommends use of PCV in national immunization program in developing countries like India where childhood mortality is very high? The GAVI alliance may make it economical. Now the 10 and 13 valent vaccine are in pipeline.

The first Polysaccharide Pneumococcal vaccine was 14 valent introduced in 1977 which was soon replaced by 23 valent PPV in 1985 in world market. It covers about 85-90 percent serotypes.  The T cell independent nature of PPV make it poor immunogenic in young children, hence can not be used below two years of age. Even in 2 to 5 years of age, the immunogenicity may not be seen for all the 23 serotypes. The antibody response is not only poor quantitatively, but also the quality, avidity of antibodies unsatisfactory.

Though combined PCV & 23PS schedules have been recommended with the assumption that PCV primed children may have good anamnestic response to serotypes in PCV as well as in non PCV-7 strains, the recent data seems not to support this fact.