Nobody expected polio eradication would take this long, but the campaigns over the last 35 years to vaccinate all children against the disease represent a major victory for global health: the fact that we have reduced the number of cases by 99 % means we have almost achieved 20 million people who would otherwise have suffered paralysis can now walk.
Now we must complete the task of ridding the world of polio. For this reason, in addition to combating naturally occurring poliovirus (also called wild poliovirus) in Afghanistan and Pakistan, the Global Polio Eradication Initiative (GPEI) is focusing on places where polio is most likely to occur. Children from infection and spread of vaccine-derived polioviruses (also called “poliovirus variants”), particularly type 2. These include northwestern Nigeria, southeastern Democratic Republic of Congo (DRC), northern Yemen and southern Somalia, where more than 84 cases worldwide % of these cases have occurred recorded since January 2022.
Insecurity, lack of infrastructure and terrain challenges make it difficult to provide basic health services to children in these areas, let alone vaccines. Such low-immunity environments are particularly vulnerable to outbreaks of poliovirus variants, which can occur when the active but weakened virus from the oral polio vaccine is allowed to circulate in unvaccinated or poorly immunized communities. The tragedy is that over time the virus can regain strength and cause paralysis in children.
Stopping the spread of poliovirus variants in Nigeria, Somalia, Yemen and the Democratic Republic of Congo is critical to a polio-free world, but achieving this will not be easy. Fortunately, all of these countries have eliminated the natural poliovirus in the past, and a similar approach can be implemented to permanently end variant outbreaks.
Nigeria, in particular, has demonstrated how outbreaks can be contained by improving population immunity through high-quality vaccination campaigns. In 2020, this country – along with the rest of the WHO African region except Somalia and Egypt – was declared free of natural polio, marking the end of a decades-long campaign for a healthier future for its children. But poliovirus variants circulated slowly and stealthily. In 2021, the numbers skyrocketed, resulting in more than 400 children in the country becoming paralyzed over the course of 12 months.
The Nigerian government has made a vigorous effort to eradicate polio, responding forcefully to the rapid rise in poliovirus variants and managing to reduce cases by 95% compared to the 2021 peak. Not only is the polio map shrinking, but cases are fewer and confined to smaller areas, as is the genetic diversity of the virus, interrupting existing outbreaks and preventing new ones. Perhaps most importantly, immunity to vaccine-derived polioviruses is increasing.
Nigeria’s success in controlling this explosive outbreak can be attributed in large part to the pioneering introduction of the new oral polio vaccine type 2 (nOPV2), which was developed with greater genetic stability than its predecessor and therefore has less likely to revert to a form that can cause paralysis. This innovative tool, coupled with increased vaccination efforts in communities with low vaccination rates, reduced new outbreaks of poliovirus type 2 variants. Furthermore, after administering 450 million doses of nOPV2 to children worldwide, Nigeria now faces only two strains of nOPV2 as of March 2021. The virus has fallen from seven at the start of its spread.
Nigeria has already defeated polio… and can do it again
Strong political commitment was also essential in the implementation of this vaccine: the creation of the Presidential Task Force to Eradicate Polio ensured that the fight against this disease remained visible on the political agenda. In addition, programs such as the Women’s Network to Reorient the Community, supported by the Aliko Dangote Foundation, contributed to success by enabling women – who make up the majority of community health workers in remote areas – to identify children, who lacked doses and encourage their communities to adopt the vaccine. These initiatives improved parents’ and caregivers’ access to essential health services.
Nigeria is not the only country that has made progress. In Somalia, which is facing the longest outbreak of poliovirus variants, GPEI is working with other organizations to set up mobile health camps to vaccinate more than half a million children against polio and provide newborn, nutritional and healing services . In the Democratic Republic of Congo, the use of digital mapping tools allowed health workers to reach thousands of unvaccinated children, and the government is setting an example for the world by convening presidential forums on vaccinating and eradicating the disease. Polio (current example). in June).
Emergency response centers have been established in each of these countries, improving the speed and quality of their responses to polio outbreaks. and in many cases they also serve to ward off other threats such as Covid-19 and measles. These innovations, along with increased use of nOPV2, have already improved immunity and reduced the number of cases and the genetic diversity of the virus in priority areas.
The goal of eradicating polio is within our reach but requires a collective effort. To achieve a polio-free world, international donors must increase their financial support – an important factor for progress in Nigeria and elsewhere. The governments of the affected countries must also work harder than ever to eradicate this disease on their territory.
Nigeria has already defeated polio…and it can do it again. Let’s ensure that all countries suffering from outbreaks can put an end to them.
Andrew Stone is deputy director for polio outbreaks at the Bill & Melinda Gates Foundation.
Spanish translation by Ant-Translation.
Copyright: Project Syndicate, 2023.
Planeta Futuro is a project in collaboration with the Bill and Melinda Gates Foundation for journalistic reporting on issues of sustainable human development.
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