The worldwide impact of the seven-valent pneumococcal conjugate vaccine.
BACKGROUND
Pneumococcal conjugate vaccines (PCV) are emerging as one of the most promising means to prevent pediatric disease. The 7-valent PCV (PCV-7) has been extensively evaluated in clinical trials, and recent evidence from the introduction of PCV-7 through national immunization programs has demonstrated impact on pneumococcal disease.


METHODS
Clinical trials have shown PCV-7 to be effective against the more severe forms of pneumococcal infections: pneumonia and invasive pneumococcal disease (IPD), as well as overall child mortality. A review shows the tremendous impact PCV-7 has had to date, and the potential further benefits of the emerging multi-valent vaccines.


RESULTS
Since its introduction, the PCV-7 has substantially reduced the incidence of IPD, hospital admissions due to pneumonia and acute otitis media in numerous, mostly high income, low-disease burden countries. The reductions in IPD and pneumonia have also been observed among unvaccinated age groups in countries with routine use of PCV-7, demonstrating that PCV-7 provides herd immunity. Some settings observed an increase in rate of nonvaccine serotype IPD, yet rates of overall and vaccine-serotype IPD show marked reductions post-PCV-7 introduction. Limited data are available on the impact of PCV-7 in lower income countries. The available data from efficacy trials from The Gambia and South Africa suggest that PCV-7 will have substantial impact on reducing pneumococcal disease.


CONCLUSIONS
PCV-7 has shown dramatic reduction in disease and mortality rates in the countries in which it has been introduced. The newly introduced 10-valent and 13-valent pneumococcal vaccines are expected to have substantial disease impact, but monitoring is essential to determine their true impact and sustain further introduction of pneumococcal conjugate vaccines.
Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Sean P
SP
Fitzwater
Aruna
A
Chandran
Mathuram
M
Santosham
Hope L
HL
Johnson
D000293:Adolescent; D000328:Adult; D002648:Child; D046688:Child Mortality; D002675:Child, Preschool; D005714:Gambia / Q000453:epidemiology; D014943:Global Health; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D032521:Immunity, Herd / Q000276:immunology; D017589:Immunization Programs; D015994:Incidence; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000276:immunology* / Q000627:therapeutic use*; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D016032:Randomized Controlled Trials as Topic; D013019:South Africa / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000276:immunology; D016896:Treatment Outcome; D055815:Young Adult
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines