Pulse Polio Immunization

Pulse Polio Immunization (PPI) is a public health campaign launched by the Government of India with the aim of eradicating poliomyelitis (polio) through mass immunisation. Introduced in 1995, the programme sought to interrupt the transmission of the wild poliovirus by administering Oral Polio Vaccine (OPV) to all children below the age of five, regardless of their previous immunisation status. The campaign became one of the most ambitious and successful public health initiatives in India’s history and played a key role in the country being declared polio-free in 2014 by the World Health Organization (WHO).

Background and Origin

Poliomyelitis, commonly known as polio, is a highly infectious viral disease that primarily affects young children. It invades the nervous system and can cause irreversible paralysis within hours. Before the widespread use of vaccines, polio was one of the leading causes of disability and mortality among children in India.
The global effort to eradicate polio began in 1988, when the World Health Assembly launched the Global Polio Eradication Initiative (GPEI), spearheaded by the WHO, UNICEF, Rotary International, and the U.S. Centers for Disease Control and Prevention (CDC). India, being one of the countries with the highest polio burden, became a focus area of this initiative.
In alignment with the global goal, the Government of India launched the Pulse Polio Immunization Programme in December 1995, initially covering select states and later expanding to the entire country.

Objectives of the Programme

The main objectives of the Pulse Polio Immunization Programme were:

• To eradicate polio from India by interrupting the transmission of the wild poliovirus.
• To immunise all children below five years of age with the oral polio vaccine, regardless of their prior vaccination history.
• To increase community awareness about the importance of immunisation and hygiene.
• To strengthen routine immunisation services and improve overall child health indicators.

Implementation Strategy

The PPI campaign adopted a mass immunisation approach, involving the simultaneous vaccination of millions of children across the country within a short period.
Key features of its implementation included:

• Pulse Approach: All children under five were given two drops of the Oral Polio Vaccine (OPV) on designated National Immunisation Days (NIDs), irrespective of previous doses. This ensured uniform and mass coverage, creating herd immunity.
• National Immunisation Days (NIDs): Held twice every year, usually in January and February, when vaccination booths were set up in every locality, village, and urban ward.
• House-to-House Campaigns: Teams of health workers visited households to ensure that no child was left unvaccinated.
• Booth-Based Vaccination: Temporary booths were established in schools, bus stands, railway stations, markets, and other public places for easy access.
• Micro-Planning: Detailed mapping of populations, especially in high-risk and hard-to-reach areas, ensured comprehensive coverage.
• Cold Chain Maintenance: Continuous refrigeration systems were maintained to preserve the vaccine’s potency.
• Public Awareness and Media Campaigns: Extensive publicity using radio, television, posters, and celebrity endorsements — most notably the campaign slogan “Do Boond Zindagi Ki” (Two drops of life) voiced by Amitabh Bachchan — played a crucial role in mobilising public participation.

Phases and Progress

The Pulse Polio Programme was implemented in multiple phases:

• Phase I (1995–1999): Initial rounds of mass immunisation were conducted, focusing on states with high incidence rates such as Uttar Pradesh and Bihar.
• Phase II (2000–2005): Strengthening surveillance systems through the National Polio Surveillance Project (NPSP), established in collaboration with the WHO, to detect and monitor all cases of acute flaccid paralysis (AFP).
• Phase III (2006–2010): Intensified immunisation drives with special focus on migratory, nomadic, and slum populations. Introduction of the bivalent oral polio vaccine (bOPV), effective against both Type 1 and Type 3 poliovirus.
• Phase IV (2011–2014): India reported its last case of wild poliovirus in January 2011 in Howrah, West Bengal. Continuous vaccination and surveillance ensured no further cases occurred.
• 2014 Onwards: In March 2014, WHO officially declared India polio-free, after three consecutive years with no new cases.

Key Components of Success

Several factors contributed to the successful implementation of the Pulse Polio Programme:

• Government Commitment: Strong political will and inter-departmental coordination ensured continuity and resources.
• Partnerships: Collaboration with international organisations such as WHO, UNICEF, and Rotary International enhanced technical support, funding, and global coordination.
• Health Workforce: Millions of healthcare workers, volunteers, and social workers participated in door-to-door campaigns.
• Community Involvement: Religious and community leaders were engaged to overcome cultural resistance and misinformation.
• Improved Surveillance: The establishment of AFP surveillance systems enabled early detection and rapid response to any suspected cases.
• Innovative Approaches: Use of mobile teams to reach migrant populations, riverine areas, and conflict zones ensured universal coverage.

Challenges Faced

Despite its success, the programme faced numerous challenges:

• Geographical Barriers: Reaching children in remote, flood-prone, and mountainous regions required extraordinary logistical efforts.
• Socio-Cultural Resistance: Misconceptions about vaccine safety and fertility led to initial reluctance in some communities, particularly in northern India.
• High Population Density: In states like Uttar Pradesh and Bihar, poor sanitation and dense populations made virus transmission difficult to control.
• Migrant and Mobile Populations: Constant movement of people posed risks of reintroduction of the virus into polio-free areas.
• Cold Chain Maintenance: Ensuring vaccine potency across India’s vast and diverse climate was a constant challenge.

Impact and Achievements

The Pulse Polio Immunization Programme achieved monumental public health milestones:

• Interruption of Wild Poliovirus Transmission: India’s last polio case occurred in 2011, marking the end of endemic transmission.
• Polio-Free Certification: In 2014, the WHO South-East Asia Region, including India, was certified polio-free.
• Strengthening of Health Systems: The programme enhanced infrastructure for routine immunisation, cold chain systems, and disease surveillance.
• Behavioural Change: Public awareness about immunisation, hygiene, and sanitation improved significantly.
• Global Recognition: India’s success became a model for other developing countries struggling with polio eradication.

Transition and Continuation

After achieving eradication, India continues polio surveillance and supplementary immunisation to prevent reintroduction of the virus:

• Routine pulse polio rounds are still conducted annually as a preventive measure.
• Surveillance of environmental samples (sewage water) continues to detect any poliovirus presence.
• The use of bivalent OPV has been supplemented by the inactivated polio vaccine (IPV) in routine immunisation schedules, ensuring long-term immunity.

Global Context

At the global level, polio remains endemic only in a few countries such as Afghanistan and Pakistan. India’s achievement demonstrated that even high-population, low-resource nations can eradicate the disease with sustained effort. The country’s strategies are now being adopted globally for other vaccination and disease eradication programmes.