In a clinical trial conducted on nearly 40,000
young children in Soweto, South Africa, a new vaccine aimed at nine
strains of pneumonia reduced incidence of the disease in fully vaccinated
children by 25 percent.
In addition, the vaccine reduced the incidence of invasive pneumococcal
disease (pneumococcal bacteria in the bloodstream) by more than
83 percent in non-HIV-infected children and by more than 65 percent
in HIV-infected children. The vaccine also significantly reduced
the incidence of invasive pneumococcal disease caused by antibiotic-resistant
strains by between 56 and 67 percent, depending on the type of resistance.
The study took place between 1998 and 2000, with follow-up through
2001. The results were published in the Oct. 2 issue of The
New England Journal of Medicine.
Participating institutions included Emory, the University of the
Witwatersrand in South Africa, Johns Hopkins University and Wyeth
Pharmaceuticals, under the auspices of the World Health Organization
(WHO) and the Medical Research Council of South Africa. Keith Klugman,
professor of international health in the Rollins School of Public
Health and professor of medicine in the School of Medicine, was
principal investigator of the study.
The clinical trial randomized two groups of infants to receive either
three doses of the conjugate vaccine or placebo. In addition, all
children received Haemophilus influenzae type b (Hib) conjugate
vaccine. The scientists tracked the conjugate vaccine’s effectiveness
over a four-year period through active surveillance of children
with pneumococcal disease at the large academic hospital serving
Antibiotic-resistant strains of pneumococci are common in the community,
and HIV infection is the leading risk factor for invasive pneumococcal
disease. The overall mortality rate in the clinical trial was reduced
by 5 percent among all children and by 6 percent among those with
"With this reduction in the incidence of pneumonia in the developing
world, we could potentially save more than 500,000 lives each year,"
Klugman said. "In addition, no vaccine previously has been
documented to prevent pneumococcal disease in HIV-infected children,
and our study showed a 50 percent reduction in that group.
"In an era in which there is little to offer children with
HIV, we can reduce invasive disease by providing this vaccine to
all children," he continued. "Our study provides evidence
to support the use of this vaccine to prevent invasive pneumococcal
disease, reduce antibiotic resistance and diminish the incidence
of pneumonia in children."
According to the WHO, pneumonia is the leading cause of death in
children worldwide and is responsible for approximately 4 million
deaths a year. Most of these deaths occur in developing countries.
Strepto-coccus pneumoniae, the primary bacterial pathogen leading
to pneumonia, has become increasingly resistant to antibiotics.
The new vaccine holds promise for all U.S. children to prevent invasive
pneumococcal disease and bacterial meningitis, and it can be administered
in infancy. It targets seven strains of pneumococcal disease, while
the vaccine used in the South African trial targets two additional
strains that are prevalent in developing countries. The conjugate
vaccine is currently under development for both developed and developing
countries but has not yet been licensed for use.