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If there is one disease that illustrates the value of vaccination, that disease is polio. Thanks to the vaccines that prevent it, today polio is totally unknown among the younger generations in industrialized countries, where most physicians have never seen a single case. Following the official eradication of smallpox in 1980, polio is on the verge of becoming the second infectious disease to be eliminated worldwide.
This success at fighting polio has been facilitated by the utilization of two complementary vaccines.
The injectable vaccine (IPV), developed in 1954 by Jonas Salk (and sometimes adapted, notably by Pierre Lépine of the Pasteur Institute in Paris), uses an inactivated, or "killed" virus. The Francis Field Trial to test Salk's vaccine was the largest medical experiment in history. The success of the IPV is one of the landmark achievements of the 20 th century.
The oral vaccine (OPV), which is made using live, attenuated strains of the virus, was developed by several teams in the late 1950s, but it was Albert Sabin's vaccine that was adopted universally. It offers the advantage of being easy to administer and practical for use during immunization campaigns in developing countries. The drawback with the oral vaccine is that the attenuated virus used in the vaccine may revert to pathogenicity, causing paralysis in one out of every 750,000 to 2.5 million people vaccinated, depending on the source.
The injectable vaccine contains three viral strains in the following proportions: 40 units of type 1; 8 units of type 2; and 32 units of type 3. Generally speaking, the oral vaccine contains one live, attenuated strain of each type. |
Besoins financiers de l'initiative mondiale d'éradication de la poliomyélite (2004-2008)...
Polio vaccines illustrate the effectiveness of vaccination
