Before the development of the first poliovirus vaccine in 1955, poliomyelitis paralysed and killed up to half a million people every year.
By 2000, mass vaccination campaigns, armed with new types of oral polio vaccines, had almost eradicated wild poliovirus, except for a few isolated regions.
In 2020, the whole African region was declared free of wild poliovirus, leaving just two countries yet to stop the spread of the disease: Afghanistan and Pakistan.
Mass immunization programs had Pakistan on the brink of eradicating polio in 2023, with just six remaining cases of the wild form of the virus. But now, cases are climbing again — 73 cases were reported in 2024.
“It has spread to all districts of Pakistan. We’ve snatched defeat from the jaws of victory,” said Zulfiqar Bhutta, Hospital for Sick Children, Toronto, Canada.
The reason, Bhutta writes in a commentary in the Lancet, is that cases of poliovirus are spilling over the border from Afghanistan. The genetic strains of wild poliovirus in Pakistan are all from Afghanistan.
Why is poliovirus spreading from Afghanistan to Pakistan?
Bhutta leads groups working on child immunization strategies in conflict zones. He was involved in the largest trials of poliovirus vaccine interventions in Afghanistan, working “very successfully” with the Taliban until a year ago.
But poliovirus eradication programs have faced multiple setbacks over the years since the Taliban takeover of Afghanistan in 2021. Public health officials say “vaccine hesitancy” (when people don’t want to take vaccines), poor sanitary conditions and regional insecurity have all sabotaged vaccination efforts.
Bhutta, who was back in Afghanistan in December, said the Taliban did not allow female health professionals to work, and that impedes public programs, including vaccinations.
“Some health workers have got into the communities. But they’ve somehow dispersed the goddamn poliovirus over the entire area,” Bhutta said.
Now, health authorities do not have reliable data on the number of poliovirus cases in Afghanistan. The poliovirus can cause paralysis in extreme cases, especially young children, and can be fatal if the virus affects breathing muscles.
“It’s a virus that does not want to be eradicated, so give it an inch and it will take a yard,” Bhutta said.
Getting back to successful mass polio immunization programs
Pakistan has spent an estimated $10 billion on poliovirus immunization programs in the region since 2011. Despite two decades of challenges, including political instability, drone strikes in its tribal areas, and conflict in Afghanistan, the program almost succeeded in completely eradicating polio within Pakistan’s borders.
But provinces in Pakistan have different immunization rates. While in Punjab, 85% of children are vaccinated, rates are as low as 30% in Balochistan. Until vaccine coverage reaches 85-90% in all provinces, it is unlikely wild poliovirus will be fully eradicated from the region.
Bhutta is calling for a major strategic review to strengthen routine immunization programs, not just for polio, but for other infectious diseases, as well.
“This is how countries like India eradicated polio,” Bhutta said. “They strengthened their routine immunization programs at the same time.”
“It can certainly work in Pakistan,” Bhutta said. “It’s a question of where you want to put resources.”
Bhutta: Work with the Taliban on polio eradication
Eradicating poliovirus in the region is impossible, Bhutta said, unless international and Pakistan-based health authorities work with the Taliban government in Afghanistan — which they don’t at the moment. Until then, cases will continue to spill over the border, he said.
International health agencies have worked with the Taliban before to deliver smallpox vaccines during periods of negotiated peace, when health workers could go in and give the vaccine.
“Taliban are not the enemy. Ultimately, they have the same health concerns that everyone else does,” Bhutta said.
What’s crucial to eradicate polio in the region, he said, is to address general health programs for women and children, not just polio. Without proper sanitation and broader disease prevention programs, polio will just come back.
According to data from the WHO, suspected cases of several infectious diseases, including pneumonia, dengue fever and measles, have been rising in Afghanistan in the last six months.
“There are so many health needs in this region, needs for children with malnutrition, needs for children with disease prevention and management. To go in and say all we want to do is polio, does not make sense,” Bhutta said.
