Vaccine-Derived Polio Virus Detected, Pg 5

Key Highlights:

• A Vaccine-Derived Polio Virus (VDPV) was detected in a sewage sample collected on June 5 from the Vijay Nagar sewage pumping station in Ghaziabad.
• Following the detection, authorities initiated a door-to-door survey covering approximately 30,000 households and 5,421 homes with 2,590 children below five years across 12 localities.
• The detected strain is largely non-virulent and has remained contained, with similar instances previously reported in Varanasi and Meghalaya.
• India was certified polio-free by the World Health Organization (WHO) on March 27, 2014, after its last wild polio case was reported on January 13, 2011.
• The surveillance efforts are being monitored by the Uttar Pradesh government, the National Centre for Disease Control (NCDC), and the WHO.

Detailed Insights:

• The detection of VDPV in sewage is part of routine environmental surveillance, a crucial component of India's polio monitoring program to detect virus circulation before human cases emerge.
• Environmental surveillance involves regular collection and testing of sewage samples from selected sites nationwide to detect poliovirus in fecal matter.
• VDPVs originate from the Oral Polio Vaccine (OPV), which contains a weakened live poliovirus that can briefly replicate in the gut and be excreted.
• In rare instances, particularly in areas with low population immunity, this weakened virus can genetically alter and regain the ability to cause paralysis.
• Despite being polio-free, India maintains high vigilance through environmental surveillance and Acute Flaccid Paralysis (AFP) surveillance to rapidly detect any poliovirus circulation.
• The ongoing survey aims to assess population immunity and implement targeted vaccination campaigns if needed, reinforcing the importance of sustained high vaccination coverage.
• The Global Polio Eradication Initiative (GPEI), a partnership including the WHO and UNICEF, supports such surveillance efforts globally.

Key Concepts Involved:

• Vaccine-Derived Polio Virus (VDPV): A rare strain of poliovirus that has genetically changed from the weakened virus in the Oral Polio Vaccine (OPV) and can cause paralysis.
• Oral Polio Vaccine (OPV): A live-attenuated vaccine administered orally that provides strong gut immunity but carries a rare risk of the weakened virus mutating.
• Environmental Surveillance: The systematic collection and testing of sewage samples to detect poliovirus circulation in a community, serving as an early warning system.
• Acute Flaccid Paralysis (AFP) Surveillance: The gold standard for detecting cases of poliomyelitis by reporting and investigating all cases of sudden onset of paralysis in children under 15 years.