PNEUMOCOCCAL VACCINE SIGNIFICANTLY REDUCES PNEUMONIA, PNEUMOCOCCAL
DISEASE,AND ANTIBIOTIC RESISTANCE IN SOUTH AFRICAN CHILDREN
Vaccine Has Significant Effect on Disease in Both HIV- and non-HIV-Infected
ATLANTA In a clinical trial conducted in nearly 40,000 young children
in Soweto, South Africa, a pneumococcal conjugate vaccine aimed at nine
strains of disease reduced the incidence of pneumonia 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 are published in the October 2 issue of The New England
Journal of Medicine.
Participating institutions included Emory University, 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 P. Klugman,
MD, professor of international health in Emory University’s Rollins
School of Public Health and professor of medicine in Emory University
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 the community of Soweto.
Antibiotic-resistant strains of pneumococci are common in Soweto, and
HIV infection is the leading risk factor for invasive pneumococcal disease.
The overall mortality rate in the clinical trial was reduced by five
percent among all children and by six percent among HIV-infected children.
According to the WHO, pneumonia is the leading cause of death in children
worldwide and is responsible for approximately four million deaths a
year. Most of these deaths occur in developing countries. Streptococcuus
pneumoniae, the primary bacterial pathogen leading to pneumonia, has
become increasingly resistant to antibiotics.
A vaccine is now indicated for all U.S. children to prevent invasive
pneumococcal disease and bacterial meningitis, and is administered in
infancy. The vaccine targets seven strains of pneumococcal disease,
while the vaccine used in the South African clinical trial targets two
additional strains of pneumococcus that are prevalent in developing
countries. The 9-valent conjugate vaccine is currently under development
for both developed and developing countries, but has not yet been licensed
"With this reduction in the incidence of pneumonia in the developing
world, we could potentially save over 500,000 lives each year," said
Dr. Klugman. "In addition, no vaccine has previously 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 to children with HIV, we can clearly reduce invasive
disease by providing this vaccine to all children. 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."