World Polio Day, celebrated this year on October 24, highlighted decades of extraordinary public health efforts to eradicate polio, a virus that attacks the human nervous system, causing paralysis and sometimes death. Task Force polio teams on the frontlines of this global effort see both the need to honor progress and to invest more to get the job done.
Effective polio vaccines have been available since the 1950s, but as recently as the 1980s polio was present in 125 countries, paralyzing roughly 1,000 children a day. In 1988 the World Health Assembly launched the Global Polio Eradication Initiative, seeking to ensure that people everywhere, particularly those most at risk in low- and middle-income countries, could be vaccinated. A wide range of partners – including national governments, the World Health Organization, UNICEF, U.S. Centers for Disease Control, Rotary International, non-governmental groups like The Task Force for Global Health and others have contributed to this work, and the incidence of polio has dropped 99% since that time. Today the wild polio virus is present in only two countries – Afghanistan and Pakistan. But outbreaks periodically occur elsewhere, including countries in Sub-Saharan Africa, primarily in poor and hard-to-reach communities.
“My message to everyone is also World Polio Day’s motto: Make polio history,” said Dr. Mesfin Weldetsadik, a senior epidemiologist with The Task Force’s polio program. “Sometimes I tell other doctors that I work on polio eradication and they’re surprised. They think it was already eradicated. North America, South America and Australia have eliminated it. Effective implementation of eradication strategies can stop transmission and eliminate the disease. It’s a matter of commitment and resource allocation.”
Tackling the last mile
Tackling “the last mile” of the initiative is complicated due to several factors. For one, differing environments call for different approaches, such as using a version of the vaccine that can be given by droplets in the mouth (the oral polio vaccine, which is easily transported and administered so can be delivered to people even in the most remote and underserved areas) versus an injectable vaccine, which requires skilled training, access to health care facilities, systems to safely dispose of used syringes and other factors. The oral vaccine is administered in environments with active ongoing outbreaks due to its ease of administration and mode of action, as it initiates intestinal immunity by producing antibodies that protect against polio infection.
Communities are safest when most people are vaccinated so that even those who aren’t vaccinated receive the benefits of “herd immunity.” This occurs when the majority of the population is vaccinated and therefore have developed antibodies against a disease, reducing its likelihood of spreading. A threshold of 80% coverage is usually recommended for herd immunity, said Dr. Victor Eboh, a senior epidemiologist with The Task Force polio team.
“People ask me how come I’m still working on polio,” said Eboh. “As long as we have one case of polio — a paralyzed child anywhere in the world — every child is at risk.”
The Task Force’s Polio Eradication Center currently has senior epidemiologists supporting vaccination programs in the Democratic Republic of Congo, Ethiopia, Nigeria, Somalia and South Sudan. The Polio Eradication Center also helps with the development of new antiviral medicines and antibodies with the potential to prevent people with weakened immune systems from excreting the virus after they have been exposed to the live vaccine (which can contribute to the spread of the virus).
Experts call for ongoing commitment and funding
WHO cites ancient Egyptian images of children walking with canes as evidence that polio has inflicted suffering on humanity for millennia. Those working on polio now say that if health systems and their funders back away from the work before the disease is eradicated, an eventual resurgence is possible, even likely.
“We still have some serious work to do to reach the finishing line. The job is not yet done,” said Assegid Kebede, a senior epidemiologist for The Task Force’s polio team. “Polio eradication is the right thing to do — a doubly right thing to do — because it will save lives and save money. Before fatigue sets in, in particular donor fatigue, we have to rush and do the right thing.”
The Task Force’s Polio Eradication Surge Capacity Program deploys a rapid response team within 72 hours after a new polio case has been detected and conducts a vaccination campaign. Team members say that evidence of the damage caused by polio and other vaccine-preventable diseases is always present when they’re working. They frequently meet survivors of childhood polio. And because many team members grew up in countries where polio was present, they have seen first-hand the risks of the disease.
“When I was growing up, I used to see kids limping,” said Fikru Abebe, a senior epidemiologist for The Task Force, who grew up in Ethiopia. “I sometimes wonder what happened to those kids. In a rural situation, if someone gets polio they may not be able to earn a living. Polio not only leaves a child paralyzed for life but also robs them of the ability to earn a living and pursue their childhood dreams, thus making them a burden to their family and the community.”
In 2020, Africa was certified as free of wild poliovirus, an achievement the Lancet said reflects the relentless efforts by governments, donors, frontline health-care workers, and communities, which saved up to 1.8 million children from polio’s crippling life-long paralysis. However, periodic outbreaks occur due to factors like vaccine-derived polio, though rare, and lack of sufficient vaccine quantities to achieve herd immunity.
“All these vaccines are very good, they work, but if you don’t have enough coverage you won’t be able to stop the circulation,” said Dr. Fabien Diomande, Director of The Task Force’s Polio Eradication Surge Capacity Program. “We don’t have enough quantity to address the need and so have to prioritize where the vaccines go, which leaves some people unprotected.”
Polio experts advise that governments and donors not relent on their efforts until total eradication.
“Once a child is paralyzed, it’s irreversible,” said Weldetsadik. “It’s a terrible situation for the child and for their parents.”
Program Director Diomande has a simple message: “I would like to tell people — the vaccinators, community leaders, governments — a lot has been done to eradicate polio, but unless we eradicate polio everywhere, no countries are safe.”
Header photo: Polio vaccine administered on the Congo River in the Democratic Republic of Congo. Photo Credit: Ibrahima Kone.
