Hyderabad: The past 3 years have seen remarkable developments in the effort to eradicate polio. In 2019, global eradication of type 3 poliovirus was declared. In 2020, Africa was classified as free from endemic polio. Wild poliovirus was confined to pockets of Afghanistan and Pakistan. But optimism is receding. Polio has returned to many parts of the world, and the upcoming replenishment to fund the eradication initiative comes amid geopolitical crises and global economic difficulties. The final stages of eradication have long been stuttering. Will 2022 be the year it finally slips away?
The epidemiological situation is concerning. COVID-19 temporarily halted the Global Polio Eradication Initiative (GPEI)'s immunisation campaigns, putting over 80 million children at risk. Consequently, outbreaks of circulating vaccine-derived poliovirus (cVDPV) tripled from 2019 to 2020, with over 1100 children paralysed. Paralysis caused by wild poliovirus in Malawi in late 2021 marked a return of the virus to Africa.
In 2022, cVDPVs have been detected in wastewater in the USA, UK, and Israel, although rapid vaccination campaigns should prevent them becoming an immediate threat to public health. Nigeria has faced a large outbreak of 415 cVDPV cases. PAHO has warned that Brazil, Dominican Republic, Haiti, and Peru are at high risk for reintroduction of polio, following dwindling vaccination rates. Global polio immunisation rates fell to 80% in 2021, the lowest rate in 14 years.
GPEI's immediate concern is money. At a pledging event in October in Germany, it will ask for US$4·8 billion from partners and donor countries, and for political commitment to eradicate polio by 2026. The strategy for 2022–26, if funded, will see the vaccination of 370 million children annually and continued surveillance for polio and other diseases in 50 countries.
But will donors be willing? Among economic instability, cost-of-living crises, and concerns over fragmentation of global health financing, governments might not see polio as important. As outlined in a World Report, the Global Fund to Fight AIDS, Tuberculosis and Malaria failed to reach its recent fundraising target. Traditional global health entities are seemingly no longer the political priorities they once were.
Also read: Overcoming challenges en route to polio eradication: Lancet
In its latest report, the GPEI's Independent Monitoring Board has warned that any recent optimism “must be tempered by some cold realities”. Although there have been reductions in cases in Pakistan and Afghanistan, widespread flooding in Pakistan has put health-care delivery at risk. Vaccinations have restarted in Afghanistan, following the near breakdown of the entire health system after the Taliban's return to power; in February, eight vaccination workers were killed. The Board emphasises the need to engage with and secure commitments from local governments in wild poliovirus’ last strongholds.
Novel polio vaccines should help control outbreaks of cVDPV and reduce the risk of new cases. A novel oral polio type 2 vaccine, using a more genetically stable virus strain, has been given emergency authorisation by WHO. Data on its performance are being collected with the goal of full licensure, and potential use outside outbreak settings. But novel vaccines have been in short supply and technical solutions alone are not enough to overcome barriers to eradication.
In fact, the fundamental aims of the eradication programme have been questioned. Writing in The Lancet Global Health, Konstantin Chumakov and colleagues argued that GPEI should refocus on eradicating poliomyelitis as a disease, rather than eradicating the virus itself. Others have urged the programme to consider the eradication goal unobtainable and focus instead on sustained control of cases.
Aidan O’Leary, Director for Polio Eradication at WHO, writes in The Lancet that, “While previous deadlines have come and gone, the Global Polio Eradication Initiative's 2022–2026 strategy has sharpened its approach to overcoming the remaining hurdles to eradication in the highest risk communities around the world”. But it is reasonable to ask whether the dedication of huge amounts of money and effort to a vertical health programme for a single disease is fair.
The GPEI has done indisputable good. Since its launch in 1988, it has overseen a 99·9% reduction in the global incidence of polio, saved more than 1·5 million lives, and spared an estimated 16 million people from paralysis. Two of the three serotypes of wild poliovirus (types 2 and 3) have been certified as eradicated worldwide. These are huge achievements. But the GPEI faces clear challenges that once again threaten the viability of the eradication programme. One thing is certain: a global resurgence of polio would be disasterous for health. (Lancet)
