World Polio Day is observed annually on 24th October. Established to commemorate Jonas Salk’s birth, the developer of an Inactivated Polio Vaccine (IPV), this day highlights the world’s continual fight against polio. The objective is to urge nations worldwide to remain watchful and diligent in their efforts to eradicate this crippling disease.
Global Efforts Towards Eradicating Polio
Over the past thirty years, the Global Polio Eradication Initiative (GPEI) has persistently monitored the global situation of polio. This initiative is led by national governments in collaboration with the World Health Organisation (WHO). WHO reports indicate a significant decrease of over 99.9% in wild poliovirus cases since 1980, which can be attributed to widespread vaccination efforts.
Understanding Polio Eradication
For WHO to certify any country as polio-free, the nation must halt the wild transmission of all three kinds of Polioviruses. Successful eradication means reducing both wild and vaccine-derived polio infection cases to zero. Eradication signifies a complete and permanent worldwide reduction to zero new cases, removing the need for any control measures. Conversely, eliminating a disease involves reducing the rate of new cases to zero or a very low defined target within a specific geographical area, requiring continued measures to prevent disease transmission resurfacing.
Recent Polio Outbreaks
In 2019, several countries reported polio outbreaks, including the Philippines, Malaysia, Ghana, Myanmar, China, Cameroon, Indonesia, and Iran. Most cases were vaccine-derived, where a rare virus strain mutated genetically from the vaccine strain. WHO suggests that when an oral vaccine-virus is excreted and allowed to circulate in an unimmunised or under-immunised population, it can mutate and cause infections. Afghanistan and Pakistan are the only two nations that have not eradicated the wild poliovirus.
The Status of Polio in India
In 2014, WHO certified India as polio-free, following three years without a single recorded case. The successful pulse polio campaign, which involved administering polio drops to all children, significantly contributed to this achievement. The last reported case due to wild poliovirus in India was on 13th January 2011.
About Polio
Polio is a crippling and potentially lethal viral infection affecting the nervous system. It has three distinct wild strains – Wild Poliovirus type 1 (WPV1), Wild Poliovirus type 2 (WPV2), and Wild Poliovirus type 3 (WPV3), which are individually and immunologically different. Although all three strains can cause irreversible paralysis or death, they each need to be eradicated separately due to their genetic and virological differences.
The Spread of Polio
Mainly transmitted by person-to-person through the faecal-oral route or less frequently, via a common vehicle such as contaminated food or water. Children under five years old are the most vulnerable victims. The virus multiplies in the intestine, from where it can invade the nervous system and cause paralysis.
Symptoms of Polio
While most people with polio do not exhibit symptoms, some experience minor symptoms such as fever, tiredness, nausea, headache, nasal congestion, sore throat, cough, neck and back stiffness, and pain in the arms and legs. In rare cases, polio infection leads to permanent muscle function loss (paralysis) and may even cause death if the breathing muscles are paralysed or if the brain gets infected.
Preventing Polio
There is no known cure for polio, but it can be prevented through immunisation. The Oral Polio Vaccine (OPV) is given orally as a birth dose for institutional deliveries, followed by primary three doses at 6, 10, and 14 weeks and one booster dose between the age of 16-24 months. In addition, an Injectable Polio Vaccine (IPV) is introduced as an additional dose alongside the third dose of DPT (Diphtheria, Pertussis, and Tetanus) under the Universal Immunisation Programme (UIP).
