The global fight against polio is reaching a significant milestone, as the world has not recorded a single case of wild polio infection in people for the past 19 weeks. According to the World Health Organization (WHO), the last confirmed cases were reported in Pakistan and Afghanistan in October and September 2023, respectively, making these nations the last remaining endemic areas for polio.

Experts are cautiously optimistic about the progress made so far in eradicating the debilitating disease. Gordon McInally, president of Rotary International and a key partner in the Global Polio Eradication Initiative (GPEI), expressed hope for the future, stating that the 19-week period without a single reported case is a significant achievement. However, he also emphasized the need to remain vigilant and not become complacent in vaccination efforts.

The GPEI has faced criticism in the past for its "almost-there narrative," as highlighted in a report by the Independent Monitoring Board. Therefore, stakeholders involved in eradication efforts are taking nothing for granted and understand the importance of sustained dedication and funding.

To officially declare global polio eradication, another 33 weeks without a reported case are required, amounting to a full year since the last incident. If the world can maintain a two-year period without any new cases, polio can be declared officially eradicated. Aidan O'Leary, the WHO's director for polio eradication, stressed the importance of aggressively closing any immunization gaps and ensuring that all communities are reached.

While the absence of confirmed cases is encouraging, there have been 34 samples of wild poliovirus detected from environmental and other sources in the first three months of this year. Surveillance samples of sewage have revealed the presence of shed virus, indicating possible transmission. O'Leary emphasized the need for this number to be reduced to zero as well.

In light of these developments, McInally and other stakeholders met with Andrew Mitchell, the minister for development in the UK, to seek continued funding. The UK government has been the second-largest contributor, after the US, in the effort to eradicate polio. McInally stressed that funding is crucial, particularly as the remaining challenges, such as reaching nomadic populations in remote areas, are formidable.

Failure to eradicate polio in Afghanistan and Pakistan could lead to a global resurgence, with WHO modeling indicating the potential for 200,000 new cases annually within a decade. Past instances of imported polioviruses causing health concerns serve as a reminder that the threat is only a plane ride away.

However, there are reasons for hope. The success in India, which will celebrate its 10-year anniversary of becoming officially polio-free on March 27, provides inspiration. McInally drew parallels with rural India, where doubts of successful eradication were proven wrong. Immunization efforts have also been intensified in Afghanistan and Pakistan, with expanded target age groups and cross-border coordination.

Another challenge that needs attention is the transmission of vaccine-derived poliovirus, which can occur when immunization rates are low, allowing for the circulation and genetic changes of weakened poliovirus strains. McInally acknowledged the concern but remained optimistic that once wild virus transmission is eliminated, vaccine-derived cases will resolve quickly.

Since the establishment of the GPEI in 1988, when there were 1,000 cases of polio daily in 125 countries, significant progress has been made. Comparing the fight against polio to running a marathon, O'Leary stated that the finish line is within sight but emphasized the need for a clear-eyed approach until the final goal of complete eradication is achieved.

In conclusion, the world stands tantalizingly close to eradicating polio, but it is imperative that vaccination efforts and funding continue to ensure that polio becomes the second human infectious disease to be eliminated in history, following smallpox. With sustained dedication and a comprehensive approach, the global eradication of polio by 2026 remains an achievable goal.