Polio remains a global health threat, despite the existence of highly successful vaccination programs. Thanks to new funding from the Centers for Disease Control and Prevention (CDC), The Task Force for Global Health is mobilizing to support global polio eradication efforts through the Polio Eradication Surge Capacity Support Team, which has the goal of addressing the current increase in vaccine-derived polio outbreaks. Additional resources are urgently needed by the partners involved in the eradication effort to effectively handle the outbreaks being seen in a variety of countries around the world.
The Problem with Polio
The virus that causes polio is highly contagious, and it spreads through contaminated fecal material. Once inside the human body, in some individuals it can find its way into the nervous system. Within hours, it can cause complete paralysis. Irreversible paralysis occurs in 1 out of every 200 people infected, and 5 to 10% of those who are paralyzed die when their breathing muscles stop functioning. (WHO).
In the early 1950s, polio outbreaks paralyzed more than 15,000 people a year in the United States (CDC), and hundreds of thousands more worldwide (GPEI). The introduction of the polio vaccine in 1955 marked a turning point for this disabling and deadly disease. By the 1960s, polio had been virtually eliminated as a public health threat in developed nations (GPEI).
Widespread immunization has been incredibly successful at stemming poliovirus cases. From 1988 to 2018, the number of wild polio cases in 125 countries where the virus once commonly spread dropped 99.99%, from 350,000 to 33 (WHO). The disease has been tantalizingly close to elimination for nearly a decade – with one of the three types declared eradicated and another not seen for seven years – yet challenges remain to completely removing this threat. A small number of people still get infected with wild polio each year in only two countries: Afghanistan and Pakistan.
While only one type of wild poliovirus still exists in two countries, another source of paralytic polio has arisen as a result of the key tool used in the eradication effort. “The oral polio vaccine contains a live but weakened form of the virus. When a child is vaccinated with the oral vaccine, the weakened virus replicates in their intestine, and they shed the virus through their stool for a period of time,” explains Erika Meyer, MPH, Global Polio Surge Project Manager at The Task Force. “If the virus circulates in the community, it can revert back to a paralytic form. If enough people in the community are vaccinated, that’s not a problem as they are protected. But if there aren’t enough kids who have received the vaccine, they can catch the paralytic form of the vaccine virus through sewage or water.”
A Surge in Polio Response
The WHO has designated polio as a Public Health Emergency of International Concern (PHEIC). Whenever a new case of wild or vaccine-derived polio is confirmed, it launches a cascade of events, including the involvement of the Global Polio Eradication Initiative (GPEI). This public-private consortium is led by national governments and directed/funded by a collaboration between the WHO, CDC, Rotary International, UNICEF, and the Bill & Melinda Gates Foundation. Each partner plays a significant role in preventing and responding to outbreaks and collectively, GPEI helps to identify and interrupt virus transmission, as well as strengthen countries’ polio surveillance and immunization systems.
The Task Force’s team of Erika and three senior epidemiologists is a new addition to global polio eradication efforts. The “surge” in the program’s title refers to the ability and speed of GPEI partners to quickly respond to new cases. “We can quickly prepare and deploy highly-qualified epidemiologists to countries that have an outbreak,” she says. The time element is critical due to the structuring of the GPEI’s Standard Operating Procedure for responding to a poliovirus event or outbreak: an investigation must be initiated within 24 hours after a case has been detected, with a rapid response team deployed within 72 hours and a vaccination campaign to follow within 14 days.
The Polio Eradication Surge Capacity Support Team works under the umbrella of the CDC, which also provides its funding. The Task Force provides additional capacity to support the CDC’s work of halting the spread of polio by providing vaccinations, analyzing surveillance data, and assessing the risk of virus spread.
The stakes in this effort are high. Failure could result in a polio resurgence – as many as 200,000 new cases each year within a decade if eradication efforts are discontinued (WHO). “Because the world is more connected than ever, the risk of disease spread and transmission, not just across borders of neighboring countries but across long distances – such as from Nigeria to India – is quite high,” says Meyer.
One of the program’s epidemiologists, Meg Sreevatsava, is currently in Indonesia responding to a documented case of vaccine-derived polio. Meg will be there for eight to 12 weeks working with that country’s Ministry of Health to identify weaknesses in the vaccination system and provide training to ministry and community health staff. “She’s going to be our eyes and ears on the ground,” Meyer says.
When eradication efforts are ultimately successful, polio cases will drop to zero. Once a country has been polio-free for three years, it receives certification of eradication. From there, the focus shifts to surveillance. The Task Force team’s job is to support the strengthening of detection systems so that it can trigger a response and dispatch a surge team immediately whenever a new case is found.
Every effort is being made with these collaborative efforts to see that polio is eradicated in the near future. “I really hope that happens soon,” Meyer says. “That would be an incredible achievement that so many people have worked on for a long time.”