The intensity of the national programs — with about 400,000 workers in Pakistan and 86,000 in Afghanistan — has recently reduced 12 genetic clusters of the wild poliovirus in the region to just two, and one of the two hasn’t been seen since November. “From a medical perspective, the virus is gasping in these last corridors,” says Dr. Ananda Bandyopadhyay of the Gates Foundation.
The virus could, of course, spread outside these regions, as it did in 2022, when international air travel carried polio to a handful of other countries, including the United States. But frontline workers in Pakistan and Afghanistan serve as a network for tracking its possible escape routes, as families move back and forth across the border.
Sheeba Afghani, a communication specialist for UNICEF’s polio program, said that when local health workers make a home visit, for instance, and find a family member absent, they ask questions, such as: “If the child is not at home, where are they? Are they out of the district? If out of the district, is it in the same city or another city?” These are questions outsiders could never ask. If the family member has crossed the border, the information gets relayed to polio workers at the reported destination, to locate newcomers in their own 75-house networks.
New tools also help track the virus as it moves in these areas. When India was struggling to eliminate polio in 2010, it had fewer than 10 sites routinely monitoring for the virus in sewage and surface water, said Dr. Hamid Jafari, the World Health Organization’s director of polio eradication in the Eastern Mediterranean region. Back then, to spot an outbreak, health officials had to wait for children to turn up with paralysis. Now, Pakistan has monitoring sites in 84 districts.
Over nine months last year, that monitoring alerted the city of Peshawar to 30 separate introductions of the virus. But the Peshawar district’s 4.7 million people did not suffer a single case of polio, said Dr. Jafari. Knowing where to look for the virus and maintaining a high level of vaccination among permanent residents kept them safe.
