|The power of immunization|
|Commentary: New agenda for vaccines|
A revolution only for some
Vaccines have changed the course of history and human development, and they continue to do so. A veritable public health revolution is occurring, with relatively recent vaccines and vaccine-delivery technologies joining and strengthening the august ranks of older tried-and-true vaccines. The promise these developments hold is enormous; the unacceptable reality is that many in the developing world will continue to be excluded from their benefits.
A vaccine now offers protection from hepatitis B (which causes liver cancer later in life), for example, and over 60 countries have added it to their routine immunization programmes. But at a cost of $1.50 per child to administer the three necessary doses, the vaccine does not reach many of those who need the protection most. Approximately $20 million would make the vaccine available in sub-Saharan Africa.
Similarly, a new vaccine against Hib (Haemophilus influenzae type b, which causes bacterial pneumonia and meningitis) has been introduced in 24 developing countries. Now, $80 million stands between the vaccine and the lives of the millions of other children at risk in developing countries, where at least 400,000 die every year from the infections Hib causes.
The list does not end there, however. There are new vaccines on the horizon to combat the largest threats to children in developing countries, such as acute respiratory infections (ARI), which kill approximately 2 million children each year. The first ever vaccine against pneumococcal infection responsible for more than half of pneumonia deaths was licensed this year in the United States. Field tests have commenced in Africa on a vaccine variety better able to combat the strains of the disease that are common in developing countries. A vaccine against respiratory syncytial virus (RSV) which causes many of the remaining deaths from ARI is under development.
Poor countries also urgently need new vaccines against diarrhoeal diseases so common where poor hygiene and sanitation, unsafe water and malnutrition occur. These diseases kill another 1.8 million children each year. Rotavirus causes one quarter of the deaths from severe dehydrating diarrhoea in young children in developing countries. While oral rehydration therapy (ORT) can be an effective treatment, prevention is essential and requires large-scale immunization along with improved sanitation and water systems.
Vaccines are also being developed for dysentery and Escherichia coli, each of which kills upwards of a half million children a year.
Malaria, endemic to much of Africa and parts of Brazil and India, causes up to half a billion illnesses and at least 1 million deaths each year, about 75 per cent of them among children under five, making a malaria vaccine especially urgent.
Other vaccines are being tested for parasitic diseases such as schistosomiasis and dengue, which infect hundreds of millions of children and adults. Until recently, these vaccines have received inadequate attention because developing countries with very limited resources were their only market.
And the story is the same for yellow fever, which kills far too many children and adults across large swaths of Africa and Latin America. A very effective vaccine has been available for 65 years, but cost keeps it out of many of the routine immunization programmes where it is needed most.