In 1988, the quest to eradicate polio was commenced and the Global Polio Eradication Initiative was launched. Eradication of a disease is a great undertaking and requires the cooperation and support of the whole world. Even then, not all diseases are created equal. Some are much easier to eradicate than others. Take smallpox for example, it has a very easily observable symptom: a rash and there are no asymptomatic carriers. Epidemiologists can then more easily recognize communities infected with smallpox.
An asymptomatic carrier is an individual that has become infected with a pathogen, but shows no signs or symptoms. Nonetheless, they can still transmit the disease to other people. Asymptomatic carriers are hard to diagnose without laboratory equipment and unknowingly, can infect countless others.
Polio has these key characteristics which make it difficult to eradicate; polio is asymptomatic. In truth, 95% of polio infections are asymptomatic. 99% of all polio cases end with a complete recovery, however, the virus remains in the population, infecting future generations and causing further harm. So when a single case of paralytic polio crops up, it means that poliovirus is widespread in the community and further cases of paralytic polio are to be expected. Hence, time and time again the disease has spread to re-infect polio-free areas around the world.
But the world has met this challenge diligently and now the global incidence of polio has been reduced by 99.9% since GPEI’s foundation. Only Pakistan and Afghanistan are classified as endemic to wild poliovirus transmission. As of August 2022, there have been 14 documented cases of the polio virus in Pakistan. There was 1 documented case in 2021 and 84 documented cases in 2020.
Why are Pakistan and Afghanistan lagging behind, while the whole world has moved on? Why is Pakistan especially so resistant to polio eradication?
Pakistan is divided into four provinces: Punjab, Sindh, Khyber Pakhtunkhwa and Balochistan. The most recent cases of polio have been found in Balochistan and Khyber Pakhtunkhwa, whereas Sindh and Punjab have been polio-free for the past two years. The principle reason is mainly due to the high immunization in Punjab and Sindh as compared to KPK and Balochistan. But the high literacy rate in Punjab and Sindh with respect to KPK and Balochistan also plays a part. In fact, there is a strong correlation between low immunization completion, illiteracy, poverty and difficulty accessing community health and immunization services. Low immunization leads to the recurrence of polio in communities. Illiteracy, socioeconomic, cultural and religious factors have all contributed to vaccine hesitancy in Pakistan. Moreover, parental refusal is a significant hindrance to the vaccination campaign due to misconceptions regarding the purpose or effectiveness of immunization.
Along with the challenges posed by the difficult geography of the Himalayan mountain range and glaciers of Khyber Pakhtunkhwa and the harsh terrain of Balochistan, health workers face many difficulties such as rumors about vaccine safety, weak health systems, conflicts and insecurities when they deliver oral poliovirus vaccines.
Another major factor that Pakistan faces is its geographical location with respect to Afghanistan. After coming into power in August 2021, the Taliban has banned door-to-door polio vaccination drives by health workers. Furthermore, attacks on health workers have been quite common, leading to shortage in willing volunteers. If you look at a map, you will notice the two provinces bordering Afghanistan are Khyber Pakhtunkhwa and Balochistan. And the transmission of the poliovirus across the border is another major factor in the eradicaton of the Poliovirus in Pakistan. As such strengthening the border between Pakistan and Afghanistan would also be a big step forward in the eradication of polio.
Roughly 20,000 wild poliovirus cases were reported in Pakistan in the early 1990s, however the polio program has reduced this by up to 99%. The final 1% would be the hardest to eradicate but with the lives of children up for grabs, we should remain steadfast in our mission of eradicating polio.