Hello everyone and welcome to this blog post! This week I will be discussing the efforts that have been made over the last few decades to eradicate polio. I will cover what polio is, how the world is trying to eradicate it and how close we are to its eradication.
Poliomyelitis, also know as polio, is a serious viral infection caused by the poliovirus, which most commonly infects children under the age of 5. It is a very infectious viral agent that is transmitted by two main routes. The first is by airborne droplets which are launched from an infected person after they cough or sneeze. The second is by the oral-faecal route, where the faeces of an infected person contaminate the sewage system of an area, contaminating the water. This water is then either drunken by other people or used in the washing of food or clothing of other people. As one might imagine, this method of transmission makes polio much more prevalent in overcrowded places with poor sewage infrastructure.
For most people, polio is not a serious disease. About 95% who are infected with poliovirus don't have any symptoms, while the majority of those who do have symptoms only have flu-like symptoms such as a fever, headache, sore throat and abdominal pain. However, because polio is a highly infectious disease, if polio spreads through a population, a large number of people are likely to experience the rare, but serious, symptoms of the disease.
In some cases, the poliovirus damages nerves in the spinal cord (which is called spinal polio), in the brainstem (which is called bulbar polio) or both (which is called bulbospinal polio). Over the hours and days following this type of attack, paralysis develops, resulting in the loss of reflexes, muscle pains and floppy, deformed limbs. In the majority these type of cases, paralysis is not permanent but disappears naturally after a few weeks or months. Nonetheless, in about 1% of cases, permanent paralysis does occur. Additionally, if the paralysis affects the muscles involved with breathing, life support may be needed for life.
Further, polio can also lead to other long-term conditions due to the paralysis, such as muscle weakness, muscle atrophy and limb deformities. Post-polio syndrome can also occur, which affects people who have been infected by polio in the past, usually 15-40 years ago. While the science behind this condition is mostly unknown, it is thought that the neurons damaged during the initial polio infection deteriorate, causing similar symptoms to the initial infection. We do know, however, that post-polio syndrome is not caused by the poliovirus lying dormant in the body and becoming activated later in life.
Unfortunately, according to nhs.uk, the treatment options for polio are limited. There is no cure for polio, so treatment revolves around managing the symptoms of polio. This includes painkillers and bed rest as well as breathing support if muscles involved with breathing get paralysed. Physiotherapy is also necessary for anyone experiencing long term impairments, such as paralysis or limb deformity, so that they can cope with their injuries.
Polio used to be one of the most serious viruses around. Indeed, at its height in the 1900s, polio killed 500,000 people every year and caused long-term disabilities in many more. As such, during the latter half of the 20th century, the eradication of polio became a priority for governments around the world.
This led to the Global Polio Eradication Initiative being founded in 1988. This initiative is a public-private partnership which was founded after the World Health Assembly voted to eradicate polio by the year 2000. The Global Polio Eradication Initiative is organised by six main groups and also receives support from most national governments. The six groups and their responsibilities are as follows:
1. The World Health Organisation. The World Health Organisation (read my blog post about them here) is responsible for planning and coordinating the work of the initiative, as well as surveillance. Surveillance is when infected people are tracked so that people who they come into contact with can be vaccinated for the disease, thus limiting its spread.
2. Rotary International. This humanitarian organisation is responsible for fundraising and recruiting volunteers. To date, the organisation has provided over 1 million volunteers and $1.8 billion in funding.
3. The CDC. The United States Centers for Disease Control and Prevention provides expertise to consult with the other partners of the initiative and ensure eradication efforts are effective.
4. UNICEF. The United National Children's Fund is responsible for distributing vaccines and developing communication strategies to make sure everyone responds positively to polio eradication measures.
5. The Bill and Melinda Gates Foundation. This foundation has contributed over $1.5 billion to this initiative. In 2011, the Gates Foundation was responsible for around 30% of the entire initiative's funding. In addition to these financial resources, the Gates Foundation also provides technical resources.
6. Gavi, the Vaccine Alliance. This public-private partnership is responsible for procuring high-quality vaccines and distributing them to immunisation programmes.
According to the Global Polio Eradication initiative, 2.5 billion children to date have now been vaccinated against polio, with the help of over 200 countries and 20 million volunteers. One of the most impressive eradication programmes took place in India of polio. India used to be one of the global hotspots for polio, constituting over 60% of all cases in 2009. From the beginning of the eradication initiative, India was always considered one of the hardest places to eradicate the disease, due to its geography. However, despite that, an army of well-trained and motivated staff, political will from all levels of government, adequate funding and support from religious leaders were collectively able to vaccinate children across the entire country. As a result, India was declared polio-free in 2014.
There are three strains of poliovirus, all of which have to be eliminated before the disease no longer exists. Currently, type 2 and type 3 polio have been eradicated, meaning that almost all countries have been declared polio-free. The last case of type 2 polio was reported in 1999, leading to that strain being declared as eradicated in 2015. Meanwhile, the last case of type 3 polio was reported in 2012, resulting in the strain being declared as eradicated in October 2019.
The last strain of polio, type 1 polio, has been mostly eradicated. Last year, there were only 94 known cases of polio. However, eradicating this strain is likely to be difficult, as it is endemic to regions such as Pakistan and Afghanistan. Not only do these regions have cultural opposition to these schemes, but they also have ongoing political conflicts which make any intervention much harder. Nevertheless, it is hoped that polio will be eradicated by the year 2023.
Polio eradication is not without opposition. For example, in Nigeria, gunmen who were opposed to polio vaccination measures instituted by the Nigerian government killed nine women who were administering polio vaccines. In addition, in western countries, increasing resistance to vaccinations could result in a resurgence of the disease.
In conclusion, polio eradication measures have been very effective to date. Almost the entire world can now be considered polio-free. However, unless funding is maintained to fully eradicate the disease, there is a chance that the disease will resurge. Indeed, some experts predict that we could get 200,000 new cases a year. As such, governments and private donors must continue to fund eradication campaigns. While the eradication of type 1 polio will be very expensive, if polio is given a chance to resurge, the vaccination campaigns would have to continue for many more years to come. This would not be sustainable in the long term and would ultimately lead to a significant loss of life and livelihood.
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