Shazia Shakeel knocks on a door in the Sattar Khan Colony of Nowshera. Three Afghan children live in the home next to the broad Kabul River in this part of northern Pakistan. Teams have stopped here many times before, but they were never able to inoculate the children against polio.
This time, Shakeel and the rest of her team won't leave until she can place drops of the oral vaccine into each child's mouth. She then draws a mark on the children's fingers so other health workers can verify the vaccinations a few days later.
Shakeel next whips out an old cell phone to send a text to a global database used to coordinate efforts to eradicate the crippling virus.
"We were facing many issues in terms of both routine immunization and polio vaccinations," Shakeel says through an interpreter. The cell phones now "make our work easy as we [can] immediately report missed and refusal cases."
Shakeel is one of more than 100,000 Lady Health Workers in Pakistan who have been providing basic medical care door-to-door since 1994. Today, these women are on the front lines fighting to eradicate polio from one of the last remaining spots in the wild. If all goes according to plan, the polio virus could be wiped out as soon as this year. If those efforts fail, some experts predict polio could surge to as many as 200,000 new cases annually.
"For me, every single child that gets paralyzed unnecessarily is a disaster," says Dr. Roland Sutter, who coordinates the World Health Organization's polio research, policy and product development.
You can be forgiven for thinking the world had already won the war against polio. Thanks to a massive vaccination campaign that stretched from the early 1950s through the '70s, the highly contagious virus had vanished from the US by 1979. In the rest of the world, though, polio was still paralyzing 350,000 people a year.
Immunization efforts ramped up in 1988, when the World Health Assembly formed the Global Polio Eradication Initiative. Fewer than 100 cases worldwide were reported last year. Today, polio is found only in Pakistan and Afghanistan, where about a dozen cases popped up in the first quarter of the year.
Polio has been tough to eradicate in those two countries. For one thing, the virus likes their hot climate, densely populated areas and poor sanitation. And then there's the violence.
"We have deep sensitivity about the polio vaccination," Taliban spokesman Ehsanullah Ehsan told The Associated Press in 2014. "We still have strong suspicions that the vaccination campaign could be used again and again to spy on Muslims."
Four years ago, the Taliban banned polio vaccination campaigns in Pakistan's Waziristan region and started killing polio workers. The Taliban in January took credit for a suicide bombing that killed 14 people in a polio vaccination center in Quetta. And in April, the Pakistani Taliban gunned down seven Karachi police officers escorting a team of polio workers. (This attack temporarily halted the door-to-door campaign while I was writing this story.)
"Vaccination teams can't operate safely in some areas," says Oliver Rosenbauer, press officer for the WHO global polio eradication department. "There are still some vaccination coverage gaps in some areas that are...imperiling the whole effort."
Filling the gaps
One of the biggest reasons for those gaps is not knowing where they are.
That's why Lady Health Workers track which Pakistani children have been vaccinated, who's missing and who has refused. Until recently, the women manually recorded those stats. Trying to make sense of the data was nearly impossible.
"Even if they were keeping records, we couldn't find them," says Asher Ali, project manager for Rotary International's polio phone monitoring project in Pakistan.
To help, Rotary International handed out basic cell phones to thousands of Lady Health Workers. Now when one of the women visits a home, she sends a shorthand text message with information that's routed to a server. The server puts the data in a spreadsheet so that all of the information can be viewed on a computer. When a health worker sees a possible polio case, she can immediately alert the broader team.
"All that's required is a simple, cheap cell phone," says Ali.
The result is a more reliable view of what needs to be done.
It turns out there's no "one size fits all" approach to eradicating polio.
Neighborhoods have all sorts of different reasons for not vaccinating kids, ranging from security concerns to community resistance and poor planning. And the virus itself can show up as different strains across regions.
That's why workers create detailed plans documenting neighborhoods' streets, homes, number of children living in each house -- and whether the families are migrants and are therefore likely to move. They then figure out how many vaccinators they need and where they have to go, where they missed kids and the number of doses they dispensed.
The Global Polio Eradication Initiative -- which includes the WHO, Rotary, US Centers for Disease Control and Prevention, United Nations Children's Fund and the Bill & Melinda Gates Foundation -- does genetic sequencing on virus samples taken from infected children to track the spread of the disease.
That lets workers "sharpen the program instead of trying to vaccinate everybody all the time," says Dr. Jay Wenger, who leads the Gates Foundation's polio eradication efforts.
There are no guarantees that polio will be wiped out. Parts of Pakistan and Afghanistan are too remote or too dangerous to reach.
But so far, it looks promising. In 2014, Pakistan reported more than 300 polio cases, its highest in a decade. By 2015, it had just 54. And this could be the year it sees its last.
Back in Nowshera, Shakeel still monitors the health of her neighbors. As soon as she hears about a birth, she's knocking on the family's door to make sure the baby's healthy and gets inoculated. And she's recording it all with her cell phone.
"It was my dream since childhood to become a nurse, but my parents wouldn't allow me," Shakeel says. "As a Lady Health Worker, I go house-to-house [to] ensure vaccinations, refer patients to hospitals and doctors and provide available medicines.
"Our communities have benefited a lot from this initiative," she says.
This story appears in the fall 2016 edition of CNET Magazine. For other magazine stories, click here.