Pulse Polio Immunization Programme

Poliomyelitis (Polio) is a viral infectious disease that can cause flaccid paralysis by affecting the central nervous system in about 0.5% of cases.

Etiopathogenesis of Poliovirus

1. Causative Agent:

• Poliovirus is an enterovirus belonging to the Picornaviridae family.
• There are three serotypes: PV1, PV2, and PV3 (PV1 is most commonly associated with paralysis).

2. Mode of Transmission:

• Fecal-oral route (primary)
• Oral-oral route (less common)

3. Pathogenesis:

• Entry: Virus enters through the mouth and multiplies in the oropharynx and gastrointestinal tract (lymphoid tissue like tonsils and Peyer's patches).
• Viremia: Virus enters the bloodstream and may spread to other sites.
• CNS Invasion: In <1% of cases, the virus crosses the blood-brain barrier or is transported via peripheral nerves to the central nervous system (CNS).
• Neuronal Damage: The virus targets anterior horn cells of the spinal cord, causing motor neuron destruction, leading to flaccid paralysis.
• Outcomes:
• Asymptomatic (90–95%)
• Minor illness (4–8%) – fever, sore throat
• Non-paralytic poliomyelitis (<1%) – aseptic meningitis
• Paralytic poliomyelitis (<0.5%)

Pharmacotherapy of Poliovirus

There is no specific antiviral treatment for poliovirus. Management is primarily supportive and preventive:

1. Supportive Treatment:

• Bed rest, analgesics for pain
• Physical therapy to prevent deformities and improve mobility
• Ventilatory support (iron lung or modern ventilators) in case of respiratory muscle paralysis

2. Preventive Pharmacotherapy (Vaccination):

• OPV may rarely cause vaccine-associated paralytic polio (VAPP) or circulating vaccine-derived poliovirus (cVDPV).
• IPV is introduced to mitigate VAPP and cVDPV risks.

Pulse Polio Immunization in India

• Launched in 1995 as part of the global polio eradication initiative following the 1988 World Health Assembly resolution.
• Targets children aged 0–5 years with polio drops during national and sub-national rounds.

Key Milestones

• 1995: Pulse Polio Programme launched
• 2009: India reported half of the global polio cases
• 2011: Last polio case in India
• 2012: WHO removed India from the list of endemic countries
• 2014: India declared polio-free

Aims and Objectives

• Immunize every child, especially in remote areas
• Ensure no child is missed during immunization
• Timely reporting of acute flaccid paralysis (AFP) cases and stool sample collection
• Rapid outbreak response immunization (ORI)
• Maintain strong surveillance systems

Steps to Maintain Polio-Free Status

• Annual high-quality immunization rounds
• Surveillance for any virus importation or circulation
• Environmental surveillance through sewage sampling

Polio Eradication and Preparedness Efforts in India

Rapid Response and Emergency Plans

• All States/UTs have Rapid Response Teams (RRTs) and Emergency Preparedness and Response Plans (EPRPs) to handle any polio outbreaks.

Preventing Importation

• Continuous Vaccination Teams (CVTs) deployed at international borders to vaccinate eligible children around the clock.
• As of August 31, 2015, approximately 7.8 million children vaccinated with OPV.
• Since March 2014, mandatory polio vaccination for international travelers to and from India and affected countries like Afghanistan, Nigeria, Pakistan, etc.
• A rolling stock of OPV is maintained for emergency response.

Introduction of IPV in Routine Immunization

• In line with the Polio Eradication & Endgame Strategic Plan 2013–2018, India introduced the Inactivated Poliovirus Vaccine (IPV) in 2015.
• IPV is given with the third dose of OPV at 14 weeks of age for infants.

Programme Outcomes

• Over 17.4 crore children under 5 years receive polio drops annually.
• Last polio case reported on 13 January 2011 in Howrah, West Bengal.
• WHO removed India from the list of polio-endemic countries on 24 February 2012.

Reference 

Malviya K, Sahoo S, Dasadiya D, Acharya V. Social and Preventive Pharmacy. 1st ed. Pee Vee (Regd.); 2021