Sixty years ago, a field test of what would become the first polio vaccine got under way in the United States, enrolling 1.8 million children in the largest clinical trial in history. Over 600,000 young volunteers received injections of the brand new Salk vaccine. Nearly a million others were observed as a control group. One year later the results were announced: the vaccine worked. For their contribution, the children in the trials received a card signed by March of Dimes President Basil O’Connor naming them “polio pioneers.”
It is hard to imagine parents today enrolling their children in a clinical trial of a brand new vaccine. Jonas Salk developed a killed- (a.k.a. inactivated-) virus vaccine. Subsequently, Albert Sabin developed a live- (a.k.a. attenuated- or weakened-) virus vaccine. Sabin’s oral polio vaccine (OPV) became the standard in the late 1960s -- until Salk’s shot was phased back in three decades later. Salk’s inactivated polio vaccine (IPV) is what is used in the U.S. today, although some other parts of the world have stuck with Sabin’s.
A global polio eradication effort began in 1988 and has vanquished polio in much of the world. That is why a statement issued Monday by the Emergency Committee of the World Health Organization is such a shock. The Committee advised that “the international spread of polio to date in 2014 constitutes an ‘extraordinary event’ and a public health risk to other States for which a coordinated international response is essential.” Several countries are now exporting wild poliovirus and others have wild polio infection but are not exporting them. In these nations, the WHO recommends, a supplementary immunization campaign is needed to protect residents and visitors.
This year, the 60th anniversary of the start of Salk’s polio vaccine trials, we ought to pause, remember, and honor the scientists who worked to end polio and the young volunteers who made it possible to declare the vaccine effective.