Karachi, Pakistan (CNN) -- With a few drops of vaccine, Gulnaz shields another child from the devastating effects of polio.
It's a simple but potentially life-saving task. It's also incredibly dangerous -- not for the children, but for Gulnaz, who works in one of the most violent parts of Karachi.
Last year, her niece and sister-in-law -- also polio workers -- were gunned down by men on motorcycles. The U.N.'s children's agency, UNICEF, said they were shot to death for vaccinating the children
But the deaths haven't stopped Gulnaz, who is using one name for safety reasons.
"Everybody in my family was suffering from shock. Some of them tried to stop me, telling me not to do this job anymore because two coffins leaving one house leaves a mark," she said.
Anti-polio campaigns have been targeted by militants ever since U.S. intelligence used a fake vaccination program to help in its hunt for al Qaeda leader Osama bin Laden in 2011. The CIA used a fake vaccination program to collect DNA samples from residents of bin Laden's compound to verify his presence there.
That wasn't a polio campaign, but the fallout still lingers. Since July 2012, at least 22 polio workers have been killed.
Still, Gulnaz remains undeterred.
"After this tragedy, I'm not scared at all. In fact, I feel even stronger and more determined," she said. "Every woman in this country who is doing this job is praying for me. When I'm working in the field I'm with my partner, but I also sense that my niece and sister-in-law who were killed are walking alongside me."
Gulnaz and her partner are escorted by paramilitary soldiers who seal off the area -- guarding each end of a street to ensure that young children get access to the crucial drops of vaccine that most parents and children around the world can simply get from their local doctor.
On Monday alone, two people were killed and 13 others were wounded in a bombing that targeted polio workers in northwest Pakistan, police said.
That blast took place on the outskirts of the violence-plagued city of Peshawar.
The bomb was detonated remotely as polio vaccines and accompanying materials were being handed out to health workers, said Najeeb-Ur-Rehman, a senior police superintendent.
Last year, a Taliban commander in northwest Pakistan announced a ban on polio vaccines for children in the region as long as the United States continues its campaign of drone strikes.
It wasn't immediately clear if the Taliban played a role in the most recent attacks.
A father's dilemma
Osman was infected with polio as a child and wanted to make sure his children were vaccinated.
But after the raid that killed bin Laden, he decided not to vaccinate his 3-year-old son, Musharraf. The boy became one of the 28 cases of detected polio in Pakistan in 2013.
"I'm not stupid or illiterate. I made sure my other children got the drops," Osman said. "But I was very angry and wary of aid workers, because if they are cooperating with spy agencies, then it's better to keep away from them. I am sad my youngest suffered, but I don't regret my decision."
Osman, who is using only one name for safety reasons, changed his mind only after the government released a booklet with a series of religious edicts from Muslim scholars telling parents that polio drops are safe.
Polio is a highly infectious viral disease that can cause permanent paralysis in just hours. It has been eradicated around the world except for three countries where it is endemic: Pakistan, Nigeria and Afghanistan.
After the number of cases spiked sharply last year, Pakistan stepped up its eradication efforts. The numbers fell from 173 in 2011 to 58 in 2012, according to the Global Polio Eradication Initiative.
"I am appealing to my fellow Pashtun society, to give their kids polio drops," Osman said.
It's a message that health care workers hope others will hear. It could not only make their jobs safer, but also save children from a lifetime of disability.