Polio Virus

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    Context

    • The West Bengal government announced the introduction of an additional dose of injectable polio vaccine as part of the Universal Immunisation Programme (UIP) for children.

    About

    • The additional dose of Inactivated Poliovirus (IPV) at nine months will protect against any polio, like Vaccine Associated Paralytic Polio or Vaccine Derived Polioviruses.
    • As of October 2022, the WHO said only Afghanistan and Pakistan remain with the indigenous transmission of wild poliovirus type 1 (WPV1) worldwide. 
    • Wild poliovirus cases have decreased by over 99% since 1988, from an estimated 350 000 cases in more than 125 endemic countries to 6 reported cases in 2021.
    • WHO on 24th February 2012 removed India from the list of “endemic countries with active poliovirus transmission”

    • Recently genetic variants of vaccine poliovirus type 2 were detected in wastewater in Jerusalem, London, and New York in early 2022.

    What is Polio Virus?

    • Poliomyelitis, also known as polio, is an infection caused by a virus (poliovirus). It is a serious, highly contagious disease that can affect a person’s nervous system.
    • There are three types of wild poliovirus:
      • WPV 1: still exists but efforts are going on to eradicate it.
      • WPV 2: eradicated.
      • WPV 3: eradicated.
    • Polio typically affects children aged 5 years or younger. It can result in muscle weakness, permanent disability, and even death.
    • One in 200 infections leads to irreversible paralysis. Among those paralysed, 5–10% die when their breathing muscles become immobilized.
    • There is no cure for polio, but there are safe, effective vaccines that, given multiple times, protect a child for life.
    • As an unintended consequence, type 2 vaccine virus variants (circulating vaccine-derived polioviruses) that mimic wild viruses’ contagiousness and neurovirulence, have been emerging and spreading.

    Efforts to Eradicate

    • In 1988, the World Health Assembly adopted a resolution for the worldwide eradication of polio, marking the launch of the Global Polio Eradication Initiative (GPEI).
    • In 1986 India was provided with a $2.6 million grant for a pilot polio vaccination campaign under the Polio eradication campaign, Polio Plus.
    • India committed to the resolution passed by the World Health Assembly for global polio eradication in 1988.
    • National Immunization nDay (NID) commonly known as the Pulse Polio Immunization programme was launched in India in 1995 and is conducted twice in the early part of each year.
    • Additionally, multiple rounds (at least two) of sub-national immunization day (SNID) have been conducted over the years in high-risk states.
    • South-East Asia Region of WHO including India has been certified polio-free by “The Regional Certification Commission (RCC)” on 27th March 2014. 

    What is the need for an extra dose?

    • The additional dose is being given besides the existing oral and injectible polio doses that have been part of the UIP.
    • The oral polio vaccine, which is made from a live virus, has the possibility of leaving the virus in the environment, which can then infect someone.
    • The injectable polio vaccine, which is made from an inactivated virus, does not leave this possibility. Besides, the absorption of the injectable vaccine is better.
    • The third dose will give enhanced protection against the disease and will be given when the child turns nine months.

    Way Forward

    • As long as a single child remains infected, children in all countries are at risk of contracting polio. Failure to eradicate polio from these last remaining strongholds could result in a global resurgence of the disease.
    • The Polio Eradication Strategy 2022–2026 lays out the roadmap to securing a lasting and sustained world, free of all polioviruses, and transition and post-certification efforts are ongoing to assure that the infrastructure built up to eradicate polio will continue to benefit broader public health efforts, long after the disease is gone. 

    Global Polio Eradication Initiative (GPEI)

    • The goal of the GPEI is to complete the eradication and containment of all wild, vaccine-related, and Sabin polioviruses, so no child suffers from paralytic poliomyelitis ever again.
    •  GPEI has helped countries to make huge progress in protecting the global population from this debilitating disease.
    • GPEI’s four pillars include Routine Immunization, Supplementary immunization, Surveillance, and Targeted mop-up campaigns.

    Source: The Hindu