Garfield Ekon
Staff Writer
The Pan American Health Organization (PAHO) is celebrating the 30th anniversary of the certification of the eradication of wild polio virus transmission in the Region of the Americas.
In 1975, the region reported nearly 6,000 cases of polio.
However, thanks to child vaccination and sustained surveillance implemented by Governments with the support of PAHO and partners, the last case of wild polio virus was detected in September 1991 in Peru.
In 1994, the region was certified as free of this disease.
“Achieving a milestone like this is not easy. It involves a lot of work, commitment, and tenacity from thousands of health workers, researchers, partners, and all the people responsible for vaccinating their children,” PAHO Director Jarbas Barbosa said.
However, Dr Barbosa warned about the persistence of poliovirus in other parts of the world. “Until we eradicate the poliovirus globally, we must maintain high vaccination coverage and adequate surveillance to detect any imported cases,” he emphasised.
Polio is a highly contagious disease that affects the central nervous system, causing acute flaccid paralysis. Although most infections are asymptomatic, in 1 in 200 cases, the virus can cause permanent paralysis in the legs or arms. Globally, polio cases have declined by more than 99 per cent since 1988, when an estimated 350,000 cases were reported in more than 125 endemic countries.
There are now just two endemic countries: Pakistan and Afghanistan. However, the poliovirus does not respect borders and can find groups of unvaccinated or under-immunized children, which could lead to outbreaks. Dr Barbosa highlighted the impact of immunisation programmes in controlling and eliminating vaccine-preventable diseases and emphasised the continued support of governments and partners, such as Rotary International and the US Centres for Disease Control and Prevention (CDC).
Despite the progress, the PAHO Director mentioned that misinformation and distrust, along with the effects of the COVID-19 pandemic, “continue to affect vaccination coverage in some areas and populations” in the region.
In 2023, 87 per cent of children in the Americas had received the third dose of the polio vaccine necessary for full immunization, a recovery from 83 per cent in 2022, but still below the recommended coverage rate. To prevent the reintroduction of the virus, “it is essential to continue working to achieve sustained coverage of more than 95 per cent uniformly in each country,” Dr Barbosa remarked.
On rare occasions, in under-immunised populations, the live attenuated virus originally contained in the oral polio vaccine can mutate and become a circulating vaccine-derived poliovirus. This virus, as it replicates in the gastrointestinal tract, can spread through faeces and sewage, circulating in the environment, and exposing unvaccinated individuals, who are susceptible to contracting polio.