ISLAMABAD, Pakistan — Pakistani officials had been hopeful that 2019 would be the year they would succeed in their campaign against polio, and declare Pakistan polio free. But a complete victory has proved elusive.

Instead, the country’s anti-polio campaign has been hobbled by recent deadly attacks on health workers and resistance from parents in some parts of the country to having their children vaccinated against the disease. Amid those challenges, new polio cases continue to surface, with eight new ones reported this year.

The polio virus has also been found in sewage samples in several cities, including Rawalpindi, adjacent to Islamabad, the capital, a worrisome sign to health officials.

Last week, a nationwide vaccine drive had to be temporarily suspended after two separate attacks that killed a female health worker and two police officers guarding a polio-eradication team.