Poliomyelitis 

Poliomyelitis (polio) is a highly contagious viral disease that primarily affects children under the age of five and is transmitted through both the faecal-oral and oral-oral routes.¹

Polio mainly affects children under five, particularly in regions with inadequate water, sanitation, and hygiene systems. Unvaccinated individuals of any age remain at risk, including those in industrialised nations.²

Global polio eradication initiative (GPEI) 

In 1988, the World Health Assembly adopted a resolution aimed at eradicating polio, to eliminate the disease and prevent its reintroduction. That same year, the Global Polio Eradication Initiative (GPEI) was launched.. Because of these global efforts, two of the three wild poliovirus (WPV) serotypes: 2 and 3, have been eliminated. Currently, only wild poliovirus type 1 (WPV1) remains endemic in Afghanistan and Pakistan.³

Monitoring and tracking of new polio cases

Outbreak Identification: Monitoring and tracking new polio cases enable health authorities to quickly identify outbreaks, facilitating prompt containment measures to prevent further transmission. 

Data Collection: It offers crucial data to evaluate the success of vaccination campaigns and pinpoint areas with low immunisation coverage that may be at risk of outbreaks.⁴

Progress Monitoring: Tracking helps global health organisations monitor progress toward eradication and make informed decisions about resource allocation for targeted interventions. 

Vaccination Strategy Evolution: By identifying and classifying new cases, especially vaccine-derived strains, monitoring ensures the continuous evolution of vaccination strategies to address emerging challenges.

Surveillance indicators of polio

Acute flaccid paralysis (AFP) surveillance

Surveillance for Acute Flaccid Paralysis (AFP) is essential for identifying poliomyelitis and includes four key steps:⁵

1. Documenting cases of AFP in children
2. Collecting and examining stool specimens
3. Laboratory isolation of the poliovirus
4. Identifying the strain of the virus through mapping techniques

Environmental surveillance

Even in the absence of paralysis cases, poliovirus can be confirmed by obtaining samples. Testing sewage or environmental samples for poliovirus can confirm infections even in the absence of paralysis cases. Two methods do it.

1. By data collection through systematic sampling
2. By monitoring the international spread of the virus in polio-free areas through ad hoc sampling⁶

Clinicians should be vigilant for acute poliomyelitis in patients who develop new-onset paralysis after a viral illness, particularly in regions with endemic polio or low vaccination rates. Symptoms can vary in severity, including mild cases as well as paralysis or respiratory failure.¹ Timely and high-quality surveillance is essential for the detection of poliovirus and for initiating vaccination efforts.⁷ Countries should monitor surveillance indicators, identify gaps, and improve their efforts through training and supervision to play an effective role in the global eradication of polio.

National reporting mechanism

Independent monitoring of polio campaigns

Independent monitoring evaluates the quality and impact of supplementary immunisation activities, identifying gaps and enabling mid-course corrections.

Key monitoring elements 

The monitoring process records:  

• Number and source of independent monitors
• Number of children monitored
• Percentage of vaccinated children (identified by marked fingers in both house-to-house and out-of-house monitoring)
• Proportion of districts monitored

Real-time data utilisation

Real-time monitoring data answers, “How many children were vaccinated?” This makes it easier to identify missing children and stop the spread of polio.⁸

Timely reporting 

Monitoring results are reported internationally within 15 days of each immunisation round.

Case reporting and data aggregation

Confirmed polio cases are reported to national health departments, which compile data through surveillance systems and submit it to global organisations such as the WHO and GPEI for international monitoring.⁵

Coordinated response system

This system ensures data flows from local to national and global levels, facilitating timely interventions and resource allocation.

International reporting mechanism

Importance of international reporting and data sharing

International reporting and data sharing are essential to the global effort to fight polio. The World Health Organisation (WHO) and the Global Polio Eradication Initiative (GPEI) work with countries to ensure the timely and accurate reporting of polio cases.¹

Standardised reporting

By using standardised surveillance systems, new polio cases are reported to the WHO by every country. These reports include detailed information on cases, laboratory test results, and epidemiological data. The WHO compiles this information to keep track of global efforts to eradicate polio, identify outbreaks, and evaluate high-risk areas. Countries also submit data on polio vaccination coverage, allowing global health organisations to identify vaccination gaps and carry out targeted interventions.⁹

Role of international health regulations (IHR)

The International Health Regulations (IHR) are vital for disease notification. Under the IHR, countries must legally inform the WHO about any public health emergencies of international concern (PHEIC), including outbreaks of polio. This obligation promotes rapid international coordination, allowing the WHO and partners like the GPEI to respond quickly with resources, vaccination campaigns, and technical support to control the spread of the virus.¹

Efficient data sharing system

This international reporting system ensures efficient sharing of polio case data, facilitating a coordinated global response to eradicate the disease.

WHO's verification and classification process: WHO has a systematic process for verifying and classifying reported polio cases. Following the report of a suspected case, stool samples are collected from the patient and sent to accredited laboratories within the Global Polio Laboratory Network (GPLN) for testing. These laboratories verify the presence of poliovirus and establish whether the case is a genuine polio infection or acute flaccid paralysis (AFP) caused by other factors.

Classification of Cases: Once poliovirus is confirmed, the WHO classifies the case into two primary categories

Wild Poliovirus (WPV): Cases caused by naturally occurring poliovirus strains, typically found in endemic regions. 

Vaccine-Derived Poliovirus (VDPV): Cases arising from the oral polio vaccine (OPV), where the weakened virus can, in rare instances, mutate and regain virulence in under-immunised populations.

Genetic sequencing for strain verification: This process is conducted on virus samples to identify the strain type and track transmission patterns. It helps determine if a case is connected to known poliovirus strains or if it signifies a new outbreak, offering vital information for targeted responses and vaccination strategies.¹⁰

Effectiveness of WHO’s Process: WHO’s rigorous verification and classification process ensures a clear understanding of polio cases, facilitating effective interventions to prevent further spread.

Real-time tracking and surveillance tools

Digital systems are vital for tracking polio outbreaks and enhancing surveillance. Tools like Geographic Information Systems (GIS), mapping tools, and mobile reporting apps improve the speed and accuracy of outbreak detection and response. They enable health authorities to see how cases are spreading geographically, pinpoint high-risk areas, and keep track of vaccination coverage in real time.

 Mobile apps enable healthcare workers to report suspected cases and vaccination efforts instantly, facilitating efficient communication between local, national, and global health organisations. Additionally, polio surveillance databases, such as the Polio Global Eradication Initiative's Surveillance System, centralise data on polio cases, environmental samples, and immunisation coverage. By incorporating real-time data, these systems enable a quicker and more coordinated response to outbreaks, improving the effectiveness of global efforts to eradicate polio.

Public health response

The response to new polio cases is a team effort led by global health organisations like the World Health Organisation (WHO) and the Global Polio Eradication Initiative (GPEI). When a new case is confirmed, these groups work together with national governments to quickly put public health measures in place, which include:

Targeted vaccination campaigns: Also known as mop-up campaigns, are held in affected areas to vaccinate all children under five. These campaigns concentrate on the outbreak region and nearby areas to prevent further transmission.

Mobilising field teams and resources: This includes deploying health workers to hard-to-reach areas, securing vaccine supplies, and setting up vaccination points.

Strengthening surveillance: Enhanced tracking of polio cases and environmental sampling to detect the virus in wastewater has been initiated.

Communication strategies: They are used to raise public awareness about the importance of vaccination and get the community involved. Global organisations like the WHO and UNICEF provide support, emergency funding, and guidance to help countries handle outbreaks and contain the virus quickly. This quick and coordinated response is vital for stopping the spread and advancing the global effort to eliminate polio.

Global progress monitoring

Global progress monitoring is crucial to the polio eradication effort, keeping the world aligned with elimination goals. Organisations like WHO and GPEI regularly report on polio cases, vaccination coverage, and outbreak responses, tracking data through global surveillance systems.  

These reports focus on confirmed cases, environmental samples, and vaccination rates in order to find immunisation gaps. Assuring openness and promoting international commitment, annual and quarterly updates provide a clear picture of progress made toward important goals. A world free of polio can be reached more quickly by addressing these gaps and directing resources to the areas that need them most.

Challenges in reporting and tracking

Reporting and tracking polio cases encounter significant obstacles, particularly in conflict zones, remote areas, and under-resourced regions.

In conflict-affected areas, insecurity restricts access to healthcare, complicating surveillance and vaccination campaigns.

Displacement of populations makes it difficult to monitor immunisation status and detect outbreaks.

Poor infrastructure, such as inadequate roads and healthcare facilities in remote regions, hampers effective surveillance and vaccine delivery.

Areas with limited resources often face shortages of trained healthcare workers and laboratory facilities, leading to delays in detecting and confirming cases.

The lack of reliable reporting systems and digital tools creates data gaps, hindering global organisations' ability to assess the virus's spread accurately.

To address these challenges, global health organisations are enhancing surveillance and reporting by training local healthcare workers, expanding mobile reporting tools, and deploying real-time digital platforms for case tracking.

Health workers can establish vaccination stations for displaced individuals and gain access to secure regions in conflict zones by collaborating with NGOs and local authorities.

Conclusion

Accurate reporting and tracking are essential to the global eradication of polio. Timely detection of new cases enables swift vaccination campaigns and containment strategies, curbing the virus's spread. Robust surveillance not only tracks eradication progress but also protects high-risk regions from outbreaks. Together, we can ensure that no kid is affected by this deadly disease and that everyone has a healthy, polio-free future.