Vaccine Prevents Deadly Pneumonia in African Children, New Clinical Trial Confirms

WASHINGTON, D.C. -- Global health leaders today presented new research showing that vaccinating infants against Streptococcus pneumoniae -- a bacterium that causes deadly pneumonia, meningitis and sepsis could substantially reduce death and serious illness among children in the developing world.  If used widely, a pneumococcal conjugate vaccine could prevent hundreds of thousands of child deaths each year.

   

In a four-year study, a team led by the UK Medical Research Council's Felicity Cutts vaccinated and followed over 17,000 young children in The Gambia to study whether a vaccine that has been shown to prevent pneumococcal disease in urban South Africa would also work in the challenging environment of rural Africa.  The results, to be published in the March 26 issue of The Lancet, show that the vaccine reduced childhood mortality by 16 percent in children who received the pneumococcal conjugate vaccine. This study is the first major randomized, controlled vaccine clinical trial in nearly twenty years to show a statistically significant reduction in overall child mortality.

   

"The results of this vaccine trial hold great promise for improving health and saving lives in resource-poor populations," said Dr. Lee Jong-wook, the director general of the World Health Organization (WHO). "The international community's task now is to continue to work together productively to make the pneumococcal conjugate vaccine widely available to children in Africa, as lives are lost every minute to pneumococcal disease. Immunizing children with pneumococcal conjugate vaccine in developing countries will be a critical intervention towards achieving a two-thirds reduction in the under-five

mortality rate, a Millennium Development Goal."

   

Streptococcus pneumoniae, or pneumococcus, is the bacterium that causes

pneumococcal disease. When they invade the lungs, these bacteria cause the

most common kind of bacterial pneumonia and can then invade the bloodstream

(bacteremia) or the tissues and fluids surrounding the brain and spinal cord

(meningitis). According to WHO, pneumococcal pneumonia and meningitis are

responsible for about 1.6 million deaths each year, even more than malaria.

And more than 90 percent of pneumococcal pneumonia deaths in children occur in

developing countries.

   

Previous studies had shown that this vaccine was effective in reducing the

number of pneumococcal infections in children in urban South Africa. But many

of the children suffering from pneumococcal disease in Africa live in rural

areas with high infant mortality rates, significant rates of malaria

transmission and very limited access to healthcare. The Gambia is

representative of these areas, and the results of the study suggest that the

deaths caused by pneumococcal infections in rural Africa are preventable. "The

trial results are highly positive and promising, and most importantly, they

demonstrate that pneumococcal vaccination can prevent these serious infections

even in a rural African setting," said Cutts.

Sponsors of and participants in this successful trial included the

National Institute of Allergy and Infectious Diseases (NIAID), part of the

National Institutes of Health (NIH); WHO; PATH's Children's Vaccine Program

(CVP); the U.S. Agency for International Development (USAID); Johns Hopkins

Bloomberg School of Public Health and the Centers for Disease Control and

Prevention (CDC). Wyeth Pharmaceuticals provided the trial vaccine.

 

    Summary of trial results

    In this trial:

    *  This vaccine significantly reduced the need for hospitalization:

       children receiving the pneumococcal vaccine had 15 percent fewer

       hospital admissions than those who did not.

    *  The nine-valent pneumococcal conjugate vaccine was 77 percent effective

       in preventing pneumococcal infections caused by the vaccine serotypes.

    *  As a result, there were 37 percent fewer cases of pneumonia in the

       children who received the vaccine compared with children who received

       the control vaccine.

 

Working with the Global Alliance for Vaccines and Immunization (GAVI),

Wyeth Pharmaceuticals has offered to provide the pneumococcal conjugate

vaccine Prevnar to The Gambia for introduction into their national

immunization program. Wyeth is also working with GAVI's PneumoADIP and other

public health partners to facilitate access to Prevnar and future pneumococcal

conjugate vaccines with expanded serotype coverage to children in developing

countries.

 

The Gambia Vaccine Trial was a randomized, double-blind, placebo-

controlled trial -- the most scientifically rigorous design for a clinical

trial -- of the efficacy of nine-valent pneumococcal conjugate vaccine against

pneumonia, meningitis, and sepsis. The study was carried out in Upper and

Central River divisions of The Gambia between August 2000 and April 2004.  All

17,437 infants enrolled in the trial received DTP (diphtheria, tetanus, and

pertussis) and Hib vaccines.  Children had follow-up visits for two years, on

average.

 

Pneumococcal disease is an infection caused by Streptococcus pneumoniae.

When these bacteria invade the lungs, they cause the most common kind of

bacterial pneumonia and can then invade the bloodstream (bacteremia) and/or

the tissues and fluids surrounding the brain and spinal cord (meningitis).

According to WHO, pneumococcal pneumonia and meningitis are responsible for

700,000 to 1 million child deaths each year and more than 90 percent of

pneumococcal pneumonia deaths in children occur in developing countries.

 

Source: Johns Hopkins School of Public Health

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