Polio vaccination schedule under the Universal Immunization program:

From 1st Jan 2023, the fIPV-3 dose has been introduced.

At 9 months 0.1 ml ID in the Left upper arm.

Milestones in polio eradication so far in India

• OPV as a tool to eliminate Polio came to India in 1967; Trivalent OPV in 1970.

• Starting in 1995,  the Pulse Polio Immunization program was conducted at least once every year across India.

• IPV was introduced in November 2015 as an additional dose along with 3rd dose of the pentavalent vaccine as a part of the Polio endgame strategy and tOPV-bOPV switch. 

• Fractional dose of IPV became a part of routine immunization in 2017.

  
  

Last cases of Polio reported in India

• Wild poliovirus type 2: 24 October 1999 in Aligarh, Uttar Pradesh  

• Wild poliovirus type 3: 2 October 2010 in  Pakur, Jharkhand

• Wild poliovirus type 1: 13 January 2011 in Howrah, West Bengal  

• WHO certified India as Polio free on 27 March 2014.

  
  

Current global scenario

• Wild poliovirus (WPV)  

  • Type 1: Causing 100% of current cases 

  • Type 2: Eradicated in 2015  

  • Type 3: Eradicated in 2019

• WPV type1 cases in Pakistan and Afghanistan till 2022.

• cVDPV − types 1, 2, and 3, with type 2 currently causing the vast majority of cases.

• 33 countries across the world, such as the U.K., the U.S., Israel, and Malawi have experienced outbreaks of vaccine-derived poliovirus.

In live attenuated OPV, 

• the virus multiplies in the intestine for several weeks and is excreted via stool, interrupting transmission of wild poliovirus by ensuring passive immunity (passage of vaccine-derived virus) to unvaccinated children in areas of poor sanitation.

• provides mucosal immunity along with an eliciting systemic immune response.

 IPV consists of inactivated (killed) poliovirus strains of all three poliovirus types.

• IPV cannot interrupt the transmission of WPV. 

• It also provides a low level of immunity.

Hence, OPV is still the vaccine of choice for containing outbreaks and eradicating polio. 

However, in areas with low immunization coverage, VDPV can mutate into the paralytic form of poliovirus. The risk of developing paralytic polio due to continued use of OPV is deemed to pose a greater risk than imported WPV.

With COVID-19 disrupting the ongoing vaccination programs and AFP (Acute Flaccid Paralysis) surveillance there is a concern about polio cases being unreported.

This necessitated the need for an extra dose of IPV to sustain the population's immunity level against Poliovirus and make our dream of eradicating Polio come true in the near future.

The hurdles

• High-Risk Groups who are the focus of the Pulse Polio Programme

  • Brick Kiln and Construction Workers 

  • Nomads 

  • Temporary and permanent slum dwellers 

  • Underserved communities.

    
    

Conclusion

• Immunization should be an integral part of primary health care where universal health care must be provided. Government cannot expect the people in the community to accept what is provided unless they receive what they need and deserve.

• The benefit of vaccination is both delayed and invisible to the community - hence the critical need for effective health education.

• High-quality clinical surveillance for acute flaccid paralysis (AFP) as well as virological surveillance is the pressing need of the hour for polio.

References

1. GPEI-OPV [Internet]. polio global eradication initiative. Available from: https://polioeradication.org/polio-today/polio-prevention/the-vaccines/opv/

2. Pulse Polio Programme: Eradication Efforts. mohfw.gov.in

3. Dunavan CP. Polio’s Precarious Future A Review of Polio: The Odyssey of Eradication and an Interview with Dr. T. Jacob John. The American Journal of Tropical Medicine and Hygiene. 2019 Mar;100(3):763.