Please note - this is a temporary window. id21 is joining forces with Eldis and therefore the id21 website has been suspended. Soon all id21 content will be available on the Eldis website.

Testing a vaccine for childhood pneumonia in the Gambia

Almost one in five of child deaths worldwide are caused by pneumonia. A vaccine against the disease could reduce many of these deaths. A vaccine tested in the Gambia has proven to be effective against pneumonia, thus reducing hospital admissions and increasing survival rates. The researchers recommend the wider introduction of the vaccine across Africa.

A study led by the UK Medical Research Council was carried out in rural Gambia to assess the efficacy of a vaccine against pneumonia and other serious diseases caused by the pneumococcal bacterium in children aged two years and younger. The study area is typical of much of rural Africa, with an infant mortality rate of about 1 in every 10 births, widespread malaria and limited access to health services.

More than 17,000 children took part in the study. Of those, about half were randomly assigned to the intervention group (those who received the vaccine) and half to the control group (those who received a placebo). The vaccine was given to children in three doses (with at least 25 days between each dose).

After inoculation, children were monitored over a two year period to determine whether they developed pneumonia that could be diagnosed via x-ray (radiological pneumonia) or clinical diagnosis (clinical pneumonia). The two groups of children could then be compared to establish the vaccine’s efficacy. Researchers found:

388 cases of pneumonia confirmed by x-ray, the most accurate diagnostic test, among children who had received the vaccine whereas 590 of those unvaccinated were diagnosed. Researchers established that the vaccine showed an efficacy of 37 percent. This efficacy level was similar in children regardless of age and sex.
Pnuemococcal bacteria cause the majority of all cases of x-ray-confirmed pneumonia in rural sub-Saharan Africa. These bacteria can also cause meningitis and septicaemia (blood poisoning). Laboratory tests in a portion of participants showed that vaccinated children had half the rate of pneumococcal pneumonia, meningitis, and septicaemia as unvaccinated children.
Admissions to hospital among the children were reduced by 15 percent.
There was an overall reduction in mortality by 16 percent among the children who received the vaccine. This mortality saving amounts to approximately 7 deaths prevented per 1,000 vaccinated children.

In sum, the study found that the vaccine is highly effective against pneumonia, reducing hospital admissions and increasing survival rates. In particular, the 16 percent reduction in mortality would suggest that pneumonia normally contributes to many more deaths than it is currently thought.

A vaccine similar to the one used in the study is already licensed and widely used in developed countries, and newer vaccines that may provide broader protection in a wider range of countries are expected to be licensed in the next three years. The study calls for:

international agencies and developing country governments to prioritise the wider use of pneumococcal vaccine in children
donors, governments and vaccine manufacturers to commit to sustainable financing and affordable prices so that the vaccine can be made available to all children in Africa
studies to evaluate newer vaccines and to make them available as soon as possible.

Source(s):
'Efficacy of nine-valent pneumococcal conjugate vaccine against pneumonia and invasive pneumococcal disease in Gambia: randomised, double blind, placebo-controlled trial', The Lancet 365: 1139-1146, by F.T. Cutts et al., 2005
HINARI subscribers can access the full-text article here. Full document.
The Gambia Pneumococcal Vaccine Trial Full document.

Funded by: National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA; World Health Organisation (WHO); The Children’s Vaccine Programme at the Programme for Appropriate Technology (PATH)

id21 Research Highlight: 27 January 2006

Further Information:
Felicity Cutts
Initiative for Vaccine Research
World Health Organisation
CH 1211, Geneva-27
Switzerland

Contact the contributor: cuttsf@who.int

Medical Research Council Laboratories, The Gambia

World Health Organisation

Views expressed on these pages are not necessarily those of DfID, IDS, id21 or other contributing institutions. Articles featured on the id21 site may be copied or quoted without restriction provided id21 and originating author(s) and institution(s) are acknowledged. Copyright © 2009 IDS. All rights reserved.

id21 is funded by the UK Department for International Development. id21 is one of a family of knowledge services at the Institute of Development Studies at the University of Sussex. id21 is a www.oneworld.net partner and an affiliate of www.mediachannel.org. IDS is a charitable company, No. 877338.