Polio is a deadly virus that mostly affects young children, spread through contaminated food and water.
Global efforts to eradicate the disease started in 1988 and infections have dropped by 99 percent: from 350,000 in 1988 to just 406 in 2013. The World Health Assembly hopes to have the disease wiped out by 2018, but challenges remain.
Despite multinational cooperation and billions spent on eradication, health workers are having a hard time eliminating polio from its last strongholds: Nigeria, Afghanistan and Pakistan.
Misinformation and distrust of immunisation programmes have led some Pakistanis to refuse vaccination. Local suspicion of vaccines, and of the health workers who often work with foreign organisations, make accessing children for immunisations difficult. The World Health Organisation (WHO) has warned that if eradication fails, there could be as many as 200,000 new cases of polio each year.
There have been 82 cases of polio reported so far this year. Of those, 66 are in Pakistan. The country remains a major global "exporter" of the disease. Outbreaks in other countries have been traced back to viruses that originated in Pakistan.
Health workers dispensing the polio vaccines in Pakistan have been attacked. At least 50 workers have been killed in more than 100 attacks on polio teams since 2011. While no one has claimed responsibility for all the killings, it is believed that they have been coordinated by the Taliban in retaliation for the US drone attacks in northern Pakistan.
Accusations against vaccine programmes in general are not entirely baseless. In 2011, it was revealed that a Pakistani physician had aided the CIA with a fake hepatitis immunisation campaign as a cover for locating Osama bin Laden. This added to existing rumours and misinformation that polio vaccines were coming from America as a means to control women's fertility, weaken children and sterilise the population.
Earlier this week on May 26 2014, Pakistan started a new polio vaccination drive in its semi-autonomous tribal regions of North Waziristan, South Waziristan, Mohmand, and parts of Khyber. But officials fear that nearly 370,000 children might miss immunisations due to poor security for the health workers.
Source: Al Jazeera