Picture a lab scientist. White coat, pensive expression, microscope in hand. Glasses, perhaps. The person you have in mind (providing you are willing to humour a stereotype or two) may have a striking resemblance to Jonas Salk, the archetypal laboratory researcher, born in New York City on Wednesday 28th October 1914 — one hundred years ago today.
The name will be familiar to many. As creator of the inactivated polio vaccine (or IPV), Salk is cemented firmly into the annals of medical history. When his vaccine hit the shelves in 1955, the annual epidemics of poliomyelitis represented a fierce insult to postwar American civility: one particularly devastating bout in 1952 caused over 20,000 cases of paralysis and more than 3,000 deaths, mostly among children. The arrival of IPV was greeted with nationwide celebrations, and Salk was praised as a worker of miracles.
IPV has been in demand ever since, and its use in several countries has been sufficient to get rid of polio. Until recently, however, Salk’s injected vaccine has largely played second fiddle in eradication efforts. When the Global Polio Eradication Initiative was launched in 1988, it favoured an alternative formulation, Albert Sabin’s oral polio vaccine (OPV), as its weapon of choice.
But the spotlight may be shifting. With the eradication programme preparing for what is hoped to be a final onslaught, IPV is poised to take centre stage once more. Indeed, the World Health Organization recently recommended that all countries introduce at least one dose of Salk’s vaccine into routine immunisation by the end of 2015.
Why is IPV so important to polio eradication plans? What does the injected vaccine offer that the oral one does not? The centenary of Salk’s birth offers a fitting occasion to consider these issues.