Two hundred years after the discovery of vaccine by the English physician Edward Jenner, immunization can be credited with saving approximately 9 million lives a year worldwide. A further 16 million deaths a year could be prevented if effective vaccines were deployed against all potentially vaccine-preventable diseases.
So far only one disease, smallpox, has been eradicated by vaccines, saving approximately 5 million lives annually.
Polio could be next. Over 80% of the world's children are now being immunized against the polio virus, and the annual number of cases has been cut from 400,000 in 1980 to 90,000 in the mid-1990s. If the year 2000 goal of eradicating polio is achieved, the United States will be able to save the $270 million a year that is currently spent on polio vaccination. The savings for Western European countries will amount to about $200 million a year.
Measles, currently killing 1.1 million children a year, is another possible candidate for eradication. Once high levels of routine immunization have been achieved, national immunization days, followed by close monitoring and 'blitzing' of any outbreaks, can eliminate the disease.
In all, vaccines have brought seven major human diseases under some degree of control - smallpox, diphtheria, tetanus, yellow fever, whooping cough, polio, and measles.
Photo: Pain now, gain later - vaccines currently in use are saving the lives of three million children a year.©
Most of the vaccines now in use have been available for several decades, but only in the last 15 years has protection been extended to the majority of children in the developing world. Only about a quarter were being immunized when, in the mid-1980s, UNICEF and WHO called for a new commitment to regularly reaching 80% of infants by 1990. In most nations, that goal was reached and has since been sustained - saving over 3 million young lives each year. As frequent disease is also a major cause of malnutrition, immunization is also helping to protect the normal growth of millions of children.
The table below summarizes the progress so far.
Progress to date against diseases for which vaccines already exist and deaths from diseases for which vaccines might be developed
(all ages) if no
|Smallpox||5.0 million||5.0 million||--||100|
|Measles||2.7 million||1.6 million||1.1 million||60|
|Neonatal tetanus||1.2 million||0.7 million||0.5 million||58|
|Hepatitis B||1.2 million||0.4 million||0.8 million||33|
|Tuberculosis||3.2 million||0.2 million||3.0 million||6|
|Polio (cases of lifelong paralysis)||640,000||550,000||90,000||86|
|Malaria/other parasitic infections||2.2 million||--||2.2 million||0|
|HIV/sexually transmitted diseases||1.3 million||--||1.3 million||0|
|Diarrhoea/enteric fevers*||3.0 million||--||3.0 million||0|
|Acute respiratory infections||3.7 million||--||3.7 million||0|
NOTE Figures for the number of deaths that would occur in the absence of immunization are generally calculated by taking the known mortality rate of each disease in the unvaccinated and applying it to the total population.
Yellow fever still causes an estimated 30,000 deaths a year but is omitted from this table because information is not available on the number of deaths currently prevented by vaccination.
* Oral rehydration therapy (ORT) is preventing approximately 1 million deaths a year from the dehydration that is one of the most common consequences of diarrhoeal disease. Vaccines, which could prevent infection, may become available.
SOURCE Estimates supplied by Children's Vaccine Initiative, Geneva, February 1996.