A Pakistani government official says the effects of the army's territorial advances in the country's northwest against militants are "already visible" in the polio vaccination programs.
"We got access to populations in Waziristan after more than two years," Prime-ministerial polio adviser Ayesha Raza told the BBC on June 3. "We have also now penetrated some formerly no-go zones in Karachi."
Officials say polio cases in Pakistan have dropped by 70 percent in 2015, with about 25 new cases since the beginning of the year.
In 2014, the country reported its highest number of cases for more than a decade -- 303.
Most polio infections are in the northwestern tribal regions where militants have targeted immunization teams.
They accuse health workers of being spies and say the polio vaccinations are part of a plot to sterilize Muslims.
Pakistan, Afghanistan, and Nigeria are the only countries where the disease remains endemic.
Afghanistan has only reported one case this year, and Nigeria reported none.