In 2024 faced an important challenge to its polio-free status, first achieved in 2014. A case of vaccine-derived poliovirus was reported in Meghalaya, denoting that even with robust immunisation efforts, the threat of poliovirus remains. Concurrently, the Gaza Strip reported its first paralytic polio case in 25 years, prompting emergency vaccination campaigns. These incidents underline the critical need for effective surveillance systems, particularly Acute Flaccid Paralysis (AFP) surveillance, which serves as an early warning mechanism for poliovirus circulation.
About Acute Flaccid Paralysis (AFP)
Acute Flaccid Paralysis is characterised by the sudden onset of weakness or paralysis in one or both limbs without prior trauma. It is a clinical syndrome that acts as important indicator for diseases like poliomyelitis. The poliovirus is the most concerning cause of AFP, leading to irreversible paralysis and, in severe cases, death. In India, any child under 15 exhibiting symptoms of AFP is promptly investigated to ascertain whether the cause is poliovirus or another condition. This includes differential diagnosis for conditions such as Guillain-Barré syndrome and transverse myelitis. Interestingly, most AFP cases present without pain in the affected limbs, which distinguishes it from trauma-related paralysis. This unique characteristic is vital for healthcare professionals during diagnosis.
The Importance of AFP Surveillance
AFP surveillance is fundamental to polio eradication efforts. It allows for early detection of poliovirus, even in areas without symptomatic cases. The World Health Organization mandates stringent AFP surveillance systems in countries committed to polio eradication. In densely populated regions like India, this surveillance is essential for safeguarding the country’s hard-won polio-free status. The recent outbreak in Meghalaya illustrates that vigilance is required even in areas with strong immunisation programmes. Vaccine-derived polioviruses can emerge when live oral vaccines mutate, emphasising the need for ongoing surveillance.
Components of AFP Surveillance
AFP surveillance comprises a coordinated network involving health workers, hospitals, laboratories, and environmental surveillance units. When an AFP case is detected in a child, it is reported to health authorities to initiate an investigation. This multi-layered reporting system includes healthcare workers, community members, and laboratories, ensuring swift detection and response. Investigations begin within 48 hours of reporting, with clinical information and stool samples collected for laboratory testing. The samples are analysed in WHO-accredited laboratories to identify the presence of wild or vaccine-derived poliovirus. Follow-up examinations are conducted to assess any residual paralysis, further aiding in distinguishing polio from other causes of AFP.
Future Directions and Global Context
Despite being polio-free since 2011 must remain vigilant as poliovirus continues to circulate in regions such as Afghanistan and Pakistan. The Global Polio Eradication Initiative stresses the importance of maintaining high levels of AFP surveillance and routine vaccination. Countries like India, which have successfully eradicated polio, must guard against reintroduction through migration or vaccine-derived strains. The recent cases in Meghalaya and Gaza serve as reminders of the necessity for constant vigilance in preventing the resurgence of poliovirus. Maintaining robust AFP surveillance will be crucial in detecting, investigating, and responding to any future cases, thereby protecting populations from this debilitating disease.
Questions for UPSC:
- Discuss the role of Acute Flaccid Paralysis (AFP) surveillance in polio eradication efforts in India.
- What are the challenges faced by India in maintaining its polio-free status?
- Explain the significance of environmental surveillance in the context of polio outbreaks.
- Analyse the implications of vaccine-derived poliovirus cases on public health in India.
- What strategies should India adopt to enhance its polio surveillance system?
