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Resurgence of Polio and Vaccine Controversy
Context:
The World Health Organisation (WHO) reported poliovirus detections in wastewater systems in Finland, Germany, Poland, Spain, and the UK since September 2024, though no human cases have been confirmed yet.
More on News:
- Polio is seeing a resurgence worldwide, with environmental samples and human cases showing both wild poliovirus (WPV) and vaccine-derived poliovirus (VDPV).
- In other parts of the world, such as Pakistan, Cameroon, Chad, and Nigeria, cases of both wild poliovirus and vaccine-derived poliovirus have been reported.
Key Highlights:
- Vaccination and Surveillance: The five European countries with detected poliovirus have strong disease surveillance and high routine immunisation rates (85-95% coverage with 3 doses of inactivated polio vaccine, IPV).
- Vaccination efforts remain critical to prevent polio-related paralysis and death, especially in areas with pockets of under-vaccination.
- Transmission Routes: Recent studies suggest that while poliovirus transmission was traditionally attributed to the fecal-oral route, respiratory transmission via throat shedding may play a critical role.
About Polio:
- Poliomyelitis (polio), is a disabling and potentially deadly disease targeting children under 5.
- Most adults are usually vaccinated against poliovirus in childhood. However, if there is uncertainty about vaccination status it is advisable to get the polio vaccine.
- It is caused by the poliovirus.
- There are three types of poliovirus: wild poliovirus type 1 (WPV1), wild poliovirus type 2 (WPV2), and wild poliovirus type 3 (WPV3).
- types 2 and 3 have been eradicated globally.
- Mostly asymptomatic: Most people who are infected have no symptoms at all.
- Transmission: The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis (can’t move parts of the body).
Current State of Polio Eradication
- Eradicated Strains:
- Type 2 wild poliovirus eradicated in 2015.
- Type 3 wild poliovirus eradicated in 2019.
- Endemic Regions: Polio remains endemic in Pakistan and Afghanistan.
- India’s Success: Declared polio-free in 2014 through sustained immunisation efforts like the “Pulse Polio Programme”.
Vaccination Strategies for Polio Eradication
- Oral Polio Vaccine (OPV): Contains a weakened poliovirus, easily administered.
- Risks: May lead to vaccine-derived poliovirus (VDPV).
- Inactivated Polio Vaccine (IPV): Contains a killed virus, administered via injection.
- Safer but costlier and requires trained personnel.
- Transition to IPV: Recommended to eliminate risks of vaccine-derived cases and ensure sustainable eradication.
Challenges in Polio Eradication
- Surveillance Gaps: Suboptimal monitoring in underserved areas and conflict zones.
- Vaccine Dilemma: Transitioning from OPV to IPV faces logistical and financial barriers.
- Public Health Preparedness: Strengthening health systems to combat resurgence and vaccine hesitancy.
- Environmental Reservoirs: Wastewater detection highlights the role of environmental factors in transmission.
Global Polio Eradication Efforts
- Global Polio Eradication Initiative (GPEI): Focuses on routine immunisation, supplementary campaigns, surveillance, and mop-up drives.
- World Health Summit 2022: Leaders pledged $2.6 billion to GPEI to end polio.
- Global Polio Eradication Strategy 2022–2026: A roadmap for achieving a polio-free world.
India’s Role in Polio Eradication
- Pulse Polio Programme (1995): Leveraged OPV with extensive door-to-door campaigns and the slogan “Do Boond Zindagi Ki” (Two drops of life).
- Routine Immunisation: Strengthened through the Universal Immunisation Programme (UIP).
- IPV Introduction (2015): Enhanced protection, especially against type 2 poliovirus.
Key Recommendations for a Polio-Free World
- Transition to IPV: Gradual replacement of OPV to eliminate VDPVs.
- Promote funding and partnerships to address cost implications.
- Enhanced Surveillance: Expand wastewater testing and use genomic analysis to monitor poliovirus circulation.
- Public Awareness: Combat vaccine hesitancy with accurate information on IPV’s safety and effectiveness.
Global Coordination: Strengthen international efforts for equitable vaccine distribution and targeted funding.
