The African Regional Certification Commission has confirmed that Africa has been declared free of wild polio. There is still no cure, but over 95% of the population has been immunised against the disease – enough to eradicate it.
After a vigorous vaccination program in remote and dangerous locations across the country, Nigeria is the last African country to be cleared of the disease, when less than a decade ago it accounted for over half of the world’s cases. Children are particularly vulnerable to the virus, so the campaign focussed on immunising young people.
Polio is a life-altering and potentially deadly virus. It is spread through the exchange of bodily fluids of those infected with it, or through contaminated water sources. Infection typically begins with flu-like symptoms and develops into permanent damage to the arms or legs whereby the limbs are left incredibly weak and practically unable to develop muscle, leaving some victims paralysed. The virus causes death in severe cases where respiratory organs are also effectively paralysed.
My grandpa contracted the disease in his late teens, and I watched as in later life he got progressively weaker – first walking with one stick, then two, until he was unable to carry any weight on his legs whatsoever. This happened because he developed post-polio syndrome, whereby sufferers of the disease experience advanced muscle-weakening years after the initial infection. While the virus might not be on our radar nowadays as the last outbreak in the UK was in the late 1970s, its horrible effects can still be felt.
The disease was first classified in 1789, as British doctor Michael Underwood described it as a ‘debility of the lower extremities’. By the end of the 19th century, the virus was making its way to Western countries, and within the next few years, polio became one of the most feared and deadly diseases worldwide.
The first vaccines were developed in the 1950s and 60s, and routine immunisation against the disease was introduced globally in the 70s to try and limit infection numbers in developing countries and eliminate outbreaks in developed nations. By the 1980s, the goal was to eradicate the virus entirely. In 1988, the Global Polio Eradication Initiative (GPEI) was set up, leading to 2.5 billion children being vaccinated across 200 countries with the help of 20 million volunteers.
Unfortunately, we can’t call polio a thing of the past just yet. The last remaining wild strand of the disease still exists in Afghanistan and Pakistan, and cases can still arise due to vaccine-derived infection. This version of the disease is caused by the oral polio vaccine which is administered in low-income countries as it’s cheaper than the intravenous alternative. This vaccine contains a live version of the virus which enters children’s intestines before being excreted, but in poor communities where sanitation is limited, faeces containing the virus can enter water sources and thus infect those who come into contact with it. If given the opportunity, this weak form of the virus can mutate to become just as vicious as the disease the vaccine was designed to prevent.
Nevertheless, it’s a huge achievement that the original form of this devastating disease has already been almost completely eliminated when just a few decades ago, 350,000 children were paralysed by it every year. The next step must be total eradication so energy can be turned to other illnesses which need desperate attention, such as malaria and HIV.
