Orris

national polio surveillance program

Reading File
Searching the Web

National Polio Surveillance Program NPSP India WHO 2024 2025

Finding Sources
Reading Web Page

https://polioeradication.org/wp-content/uploads/2025/01/Glob…

Reading File
Finding Sources
Reading File
Reading File
Reading File
Here is a detailed overview of the National Polio Surveillance Program (NPSP):

National Polio Surveillance Program (NPSP)

Background

The NPSP is a WHO-supported initiative in India, formally known as the WHO National Polio Surveillance Project. Established in the early 1990s, it provided the epidemiological backbone for India's polio eradication effort. India was certified polio-free in March 2014 - a historic achievement for a country that once had the world's highest burden of wild poliovirus. The NPSP continues to operate today as a surveillance and post-certification monitoring network.

Objectives of the NPSP

  1. Detect every case of Acute Flaccid Paralysis (AFP) in children under 15 years
  2. Ensure timely and adequate stool specimen collection from AFP cases
  3. Coordinate with WHO-accredited laboratories for poliovirus isolation
  4. Support Pulse Polio Immunization (PPI) campaigns
  5. Provide epidemiological data for targeted immunization response
  6. Monitor environmental samples (sewage) for silent poliovirus circulation

AFP Surveillance - The Core of NPSP

AFP surveillance is the primary strategy. It has four steps, per Park's Textbook of Preventive and Social Medicine:

Step 1: Finding and Reporting AFP Cases

  • All health facility staff - from district health centres to large hospitals - must promptly report every AFP case in any child under 15 years of age
  • Public health staff make active/regular visits to hospitals and rehabilitation centres to search for overlooked or misdiagnosed AFP cases
  • Benchmark: at least 1 non-polio AFP case per 100,000 children under 15 annually (2 per 100,000 in endemic regions)

Step 2: Transporting Stool Samples

  • Two stool specimens collected 24-48 hours apart, within 14 days of paralysis onset
  • Specimens stored at 4-8°C in cold boxes and transported to lab within 72 hours
  • All AFP cases tested for wild poliovirus even when clinical polio is not suspected

Step 3: Isolating Poliovirus

  • WHO-accredited labs (Global Polio Laboratory Network - GPLN) perform virus isolation
  • Wild poliovirus is distinguished from vaccine-derived poliovirus (OPV contains attenuated live strains that resemble wild virus)
  • Wild poliovirus type 2 has not been recorded since 1999

Step 4: Mapping the Virus

  • Genetic sequencing determines the geographical origin of any isolated wild poliovirus
  • Sequences compared against a global reference bank to identify importation routes
  • Results guide targeted immunization strategies

Surveillance Indicators (WHO Certification Standards)

IndicatorMinimum Standard
Completeness of reporting≥80% of expected AFP reports received on time (including zero reports)
Sensitivity of surveillance≥1 non-polio AFP case/100,000 children <15 years/year
Stool specimen adequacy≥80% of AFP cases with "adequate" specimens (2 specimens, ≥24 hrs apart, within 14 days, proper cold chain)
Follow-up≥80% of AFP cases examined for residual paralysis at 60 days after onset
LaboratoryAll specimens processed in WHO-accredited GPLN laboratory

Environmental Surveillance

  • Sewage and wastewater samples are tested for poliovirus
  • Detects silent poliovirus circulation even when no paralytic cases are reported
  • Mumbai was among the early cities with systematic environmental sampling in India
  • Under the Global Polio Surveillance Action Plan 2025-2026, environmental surveillance has been expanded as a second pillar alongside AFP surveillance

Case Reporting Requirements

All AFP cases are reported immediately to the Chief Medical Officer/District Immunization Officer with:
  • Name, age, sex of patient
  • Father's name and complete address
  • Vaccination status
  • Date of onset of paralysis and date of reporting
  • Clinical diagnosis
  • Doctor's name and contact details
Line listing of cases began in 1989 to prevent duplication, identify high-risk pockets, and track residual paralysis outcomes. Since 1992, active surveillance was extended to all AFP causes (not just polio).

Strategies for Polio Eradication in India (NPSP Framework)

  • (a) Conduct Pulse Polio Immunization (PPI) days annually - first round held December 9, 1995
  • (b) Sustain high routine immunization coverage
  • (c) Monitor OPV coverage at district level and below
  • (d) Improve AFP surveillance to detect all cases (polio and non-polio)
  • (e) Rapid case investigation with stool sample collection
  • (f) Follow-up of all AFP cases at 60 days
  • (g) Outbreak control within 48 hours of notification (even a single case is treated as an outbreak)

Pulse Polio Immunization (PPI) - Partner Program

  • PPIs are mass OPV campaigns targeting all children 0-5 years, regardless of prior vaccination
  • Two rounds 4-6 weeks apart, conducted between November and February (low transmission season; peak season is June-September)
  • Vaccine Vial Monitor (VVM) introduced in 1998 to ensure cold-chain integrity
  • India later introduced Fractional IPV (FIPV) into routine immunization in 2016

Vaccine-Derived Poliovirus (VDPV) Surveillance

A special concern after eradication certification. OPV contains live attenuated virus that can rarely mutate back to neurovirulence:
  • VAPP (Vaccine-Associated Paralytic Poliomyelitis): rare adverse event, clinically identical to wild polio
  • cVDPV (Circulating Vaccine-Derived Poliovirus): occurs when OPV-derived virus mutates and circulates in under-immunized populations
  • India is among the countries implementing iVDPV (Immunodeficiency-associated VDPV) surveillance per the GPEI Global Surveillance Action Plan 2025-2026

Current Status (2025-2026)

Per the Global Polio Surveillance Action Plan 2025-2026, India is classified at low-to-moderate risk and continues to:
  • Sustain AFP surveillance sensitivity
  • Participate in the GPLN laboratory network
  • Implement iVDPV surveillance
  • Strengthen integration of polio surveillance with broader VPD (Vaccine-Preventable Disease) surveillance systems
Sources: Park's Textbook of Preventive and Social Medicine; WHO Global Polio Surveillance Action Plan 2025-2026; Jawetz, Melnick & Adelberg's Medical Microbiology 28e
This is a shared conversation. Sign in to Orris to start your own chat.