The Polio Virus - Close To Eradication?

Also known as Poliomyelitis, polio is an infectious disease, caused by the poliovirus. Infection can result in infantile paralysis and muscle spasms in its worse cases. The virus can be ingested through contaminated food or water, and be absorbed through the gut wall. From here it is able to move to the spinal cord and paralyse its nerves.

Above: Scanning Electron Micrograph of the poliovirus (Source: Polioeradication.org)

Typically, polio is relatively prominent in developing countries, Asia containing most of the transmission. Evidence suggests that the poliovirus has been around for a very long time, some sources quoting that it infected people in the prehistoric ages. However up until the 20th century, major epidemics were simply unknown. Until this time, the virus spread was known to be endemic - this means that in an area, the virus' transmission remained fairly constant, with no real surges in infection. In the 20th century however, Europe, followed by the Americas began to experience widespread epidemic of the disease. What is interesting is that the disease saw its highest incidence in the summer months of each year.

'At its peak in the 1940s and 1950s, polio would paralyse or kill over half a million people worldwide every year' (Wikipedia).  Franklin D. Roosevelt was one of the most notable people to be infected with the poliovirus, becoming permanently paralysed from the waist and down. (However this seems quite an unusual case as the poliovirus is typically known to induce infantile paralysis. Therefore, there is debate surrounding this specific case) This is a staggering number, considering that the rates of transmission were 'controlled' only couple of decades before this period. These rather catastrophic events initiated a global medical response, with research funding increasing dramatically.

Probably one of the most known national crises with polio was the Copenhagen polio epidemic in 1952. However epidemics of equal magnitude were spreading across America at the time.

"Anyone wandering in to Ward 19 of Copenhagen's Blegdas Hospital in the autumn of 1952 would have been confronted by an extraordinary sight. In each of the seventy beds arranged in two straight lines lay a child paralysed with polio with a hollow plastic tube inserted into the trachea through a cut in the neck - a tracheostomy - to which was attached another long piece of tubing, at the end of which was a rubber bag. Next to each bed sat a young medical student who, every few seconds, would squeeze the bag, blowing oxygen through the tubing into the child's lungs and then letting go, repeating this action for six hours at a stretch[...]According to Ann Isberg, one of the children, 'it was not a sad time', rather 'like [during the] war there was a spirit of resistance - everybody was doing their best'."

 - An account describing the atmosphere in a hospital ward, housing polio patients, from 'The Rise and Fall of Modern Medicine' written by James Le Fanu, M.D. 

Special respiratory centres were then established in the Blegdas Hospital, under the initial influence of anaesthetist Bjørn Ibsen, in order to help ventilate the polio patients (whose breathing was compromised by paralysis). This was essentially the birth of intensive care. Following these events, which constituted several 'summer plagues', in 1957, Jonas Salk, an American researcher helped synthesise the first successful polio vaccine. Choosing not to patent it, he allowed the vaccine to be distributed all over the world for free. This led to a vast decline in polio cases. By the late 1980s, many described the virus 'being close to eradication' in most countries.

Above: Polio ward in Hynes Memorial Hospital in Boston, 1955 (Source: Dailymail)

Above: An Iron Lung machine, used in the assistance of ventilation/breathing in polio patients (Source: Centers for Disease Control and Prevention's Public Health Image Library (PHIL) - via Wikipedia) 

Here is one staggering statistic: 'Polio cases have decreased by over 99% since 1988, from an 
estimated 350 000 cases then, to 416 reported cases in 2013' (The World Health Organisation Polio Fact Sheet)

Despite this, new cases of polio have been emerging in Afghanistan, Pakistan and Nigeria. In 2014, the World Health Organisation saw that this surge in cases meant the declaration of a public health emergency of international concern (PHEIC). The vital key to eradicating polio completely is nationwide herd vaccinations, as the virus cannot survive for long outside a host.

The Final Stages in Eradicating Polio

As of early 2015, scientists have been collaborating internationally in order to develop a synthetic vaccine in the hope of eradicating the last remaining strain of the poliovirus. Together, the World Health Organisation and the Bill & Melinda Gates Foundation have provided a $674,000 (£438,000) grant to fund the research. The main problem with current vaccines is that because they utilise the weakened (attenuated) form of the virus, in some patients, this may initiate an immune response. This would mean that the virus can be 'reactivated' and passed on to those that have not been vaccinated. However a synthetic vaccine means no genetic material which essentially indicates that the vaccine contains no virus.


We are extremely close to eradicating the poliovirus off the face of the Earth. What a human feat that would be.


References

In addition to sources given above:
- Credit to the World Health Organisation for their information and data on the poliovirus and the polio vaccinations
- Additional Credit to BBC Science Correspondent, Jonathan Amos for his article on the new synthetic vaccine for polio, 'Synthetic vaccine sought to finally eradicate polio' (14th February 2015) Read more.
- Additional Credit to James Le Fanu's 'The Rise and Fall of Modern Medicine' which features the events surrounding the Copenhagen polio epidemic and the birth of intensive care.