A vaccine against Streptococcus pneumoniae, a major cause of childhood illness and mortality in the developing world, sharply reduced the incidence of serious pneumococcal disease among children in a large Kenyan community after it was introduced in 2011, according to a new study from researchers at the Johns Hopkins Bloomberg School of Public Health.
The study, published online in The Lancet April 15, is the first to evaluate the effect of the vaccine, called PCV10, on a large scale in Africa.
The researchers examined two time periods, 1999-2010, before the vaccine’s introduction, and 2012-2016, after its introduction, and found that the average annual incidence of serious pneumococcal disease caused by S. pneumoniae strains that the vaccine is designed to prevent dropped by 92 percent among children under five years of age.
The incidence of disease among older, unvaccinated age groups also dropped sharply, suggesting that the vaccine produced an added “herd immunity” benefit. S. pneumoniae infection can cause many serious conditions, which are broadly termed “pneumococcal disease” and include pneumonia, meningitis, ear and sinus problems, and sepsis (blood infection).
Dr. Laura Hammitt, associate professor in the Bloomberg School’s Department of International Health and clinical epidemiologist with the International Vaccine Access Center and the Center for American Indian Health at the Bloomberg School, is the study’s lead author.Friday Letter Submission