Immunization: Going the extra mileRalph H. Henderson, M.D.
Immunization is the greatest public health success story in history. Between 1980 and 1990, a massive effort raised coverage rates worldwide from 5 per cent to 80 per cent. But just as a new generation of vaccines is about to come on the market -- capable of saving millions more children's lives each year, but at much greater cost -- the momentum to sustain immunization is faltering.
Two decades ago, just 5 per cent of infants in developing countries were being vaccinated against the six major child-killing diseases. Today, about 80 per cent are being reached -- a towering achievement.
Deaths from those six diseases (measles, tetanus, whooping cough, tuberculosis, polio and diphtheria) have been slashed by 3 million a year, and at least 750,000 fewer children are left blind, paralysed or mentally disabled. Thanks to a triumphant global eradication campaign, polio is expected to follow smallpox into extinction by the end of this decade, eliminating the need for vaccination -- and saving the governments of the world $1.5 billion in vaccine, treatment and rehabilitation costs every year.
By any standard, the international immunization effort is the greatest public health story in history. And immunization is also a bargain, with a price tag of just $15 per child: $1 for the six original vaccines plus the expenses of delivery to some of the least accessible places on earth. The impact of these modest investments on the lives of children and their parents is momentous.
The future holds even greater promise. A new generation of vaccines, about to make its entrance, holds amazing potential: vaccines against increasing numbers of diseases; one-shot vaccines that eliminate the need for booster shots; vaccines aimed at ever-younger infants, to protect them at a vulnerable age; and even vaccines that are simply spread on the skin.
Fourteen new or improved vaccines have entered the market since 1980, and dozens more are in the pipeline. They will prevent some of the most pernicious killers of children, such as diarrhoeal diseases and acute respiratory infections. Experts predict that, by early in the next millennium, these antigens could be saving the lives of up to 8 million children each year.
The basic vaccines already available to combat the 'big six' diseases could save up to 2 million children still dying from vaccine-preventable disease every year -- if every child were reached.
And there's the catch. Despite the low cost of the existing immunization package, many of the world's poorest children, those most vulnerable to disease, are already falling through the vaccine net.
Sub-Saharan Africa fares the worst: Each year, almost half the children who should receive the necessary three doses of DPT vaccine to prevent diphtheria, pertussis (whooping cough) and tetanus do not. Although coverage rates in the rest of the world are higher, the fact remains that 26 million infants worldwide annually do not receive their three DPT shots.
If we don't reach these children now, with the vaccines already available, what are the prospects of reaching them with the vaccines of the future?
To safeguard the health and well-being of children, two things need to happen. First, those children not receiving the existing low-cost vaccines must be reached. Second, we must take steps now to ensure that these children are not bypassed by the wonders of the next generation of vaccines, which will cost many times more than those now in use.