Vaccine-Derived Polio in Meghalaya

Vaccine-Derived Polio in Meghalaya

Sub: Sci

Sec: Health

Context: A recent case of polio in a two-year-old child from Tikrikilla, Meghalaya has garnered significant attention. Announced on August 20, 2024, by a senior official from the Union Health Ministry, this case is notable as it represents a vaccine-derived form of polio rather than wild polio. This development is crucial given that India was declared polio-free by the World Health Organisation (WHO) in 2014, following the last reported wild poliovirus case in 2011. The occurrence of a vaccine-derived polio case has heightened alert levels in Meghalaya and raises questions about vaccination coverage and public health responses.

Current Case

Incident Overview: A two-year-old child from Tikrikilla, West Garo Hills district, Meghalaya, has been diagnosed with polio. The child initially exhibited symptoms of poliomyelitis over a week ago and was diagnosed with acute flaccid paralysis at a hospital in Assam’s Goalpara.

Health Response: Stool and other samples from the child were sent to testing centers in Kolkata and Mumbai, managed by the Indian Council of Medical Research’s National Institute of Virology. The situation is under close review by local health officials and will be reassessed as more information becomes available.

Official Statements: Chief Minister Conrad K. Sangma has emphasized the seriousness of the situation and assured that a detailed review is underway.

Understanding Vaccine-Derived Polio

Nature of Vaccine-Derived Polio: Oral Polio Vaccine (OPV): Contains a weakened form of the poliovirus, which triggers an immune response. Occasionally, this vaccine-virus can be excreted and, in populations with low immunization coverage, can circulate and undergo genetic changes.

Circulating Vaccine-Derived Poliovirus (cVDPV): In rare instances, the vaccine-virus can evolve into a form that causes paralysis. This situation is known as cVDPV.

Historical Context and Statistics: Since 2000, over 10 billion doses of OPV have been administered worldwide, reaching nearly three billion children. There have been 24 cVDPV outbreaks in 21 countries, with fewer than 760 cases reported.

Prevention and Control: Immunization Campaigns: The standard response to cVDPV outbreaks involves conducting multiple high-quality immunization campaigns to stop the virus’s transmission.

Symptoms of Poliovirus: Include fatigue, fever, headache, vomiting, diarrhoea or constipation, sore throat, neck stiffness, pain or tingling in limbs, severe headaches, and sensitivity to light.

Transmission and Reservoir: Human Reservoir: Poliovirus is transmitted solely through human contact; there are no animal vectors involved.

• NFHS Data: According to the National Family Health Survey (NFHS) data, immunization coverage in India has generally been high, but disparities exist in rural and remote areas which may affect polio vaccination rates.

Key Points to Focus On

• Nature of the Case: Emphasis on the distinction between vaccine-derived and wild polio is crucial for understanding the current situation and addressing public concerns.
• Response Measures: The role of high-quality immunization campaigns in controlling vaccine-derived outbreaks highlights the importance of maintaining robust vaccination programs.
• Surveillance and Monitoring: The importance of continued vigilance and prompt response in monitoring and managing vaccine-derived poliovirus cases.
• Immunization Coverage: Ensuring comprehensive immunization in all populations to prevent both wild and vaccine-derived poliovirus outbreaks.