The Yorkshire Post reports this week that British researchers are developing a risk free polio vaccine.
It involves designing a hoax virus which behaves like the real polio virus to trigger the immune system but has no chance of causing the disease. As well as being safe to use, it would not need refrigeration
But the words risk-free immediately make you wonder: how risky are our current polio vaccines?
The Centers for Disease Control describes polio as an infectious disease caused by a virus that invades the nervous system and can cause paralysis within hours. Polio was all but eradicated in the US, decreasing 99 percent from an estimated 350 000 cases in 1988, to 1604 reported cases in 2009. In 2010, only four countries in the world remain polio-endemic, down from more than 125 in 1988. The remaining countries are Afghanistan, India, Nigeria, and Pakistan.
The National Network for Immunization Information claims that:
The incidence of paralytic polio peaked in the U.S. in 1952 with 21,000 reported cases and numerous deaths. Following licensure of the Salk (inactivated) polio vaccine in 1955, the incidence of the disease fell dramatically. The disease was further reduced by the advent of the Sabin (oral) polio vaccine in 1961.
It goes on to say:
About 1 out of 2.4 million doses of Oral Polio Vaccine distributed in the United States actually caused vaccine-associated paralytic polio (VAPP). In an effort to reduce this terrible side effect, a new polio vaccine schedule was recommended in 1997 (two doses of Inactive Polio Vaccine followed by two doses of Oral Polio Vaccine). The new schedule decreased, but did not guarantee elimination, of vaccine-induced paralytic polio; so, effective in the year 2000, an all-IPV schedule was recommended, and Oral Polio Vaccine is no longer administered in the U.S.
Even though one in 2.4 million is astronomically small, a risk-free polio vaccine would be a great relief.
