mass vaccination campaigns ... are only possible with the involvement of a vital cadre of public health workers and volunteers

In our April 2012 issue, we published an Editorial entitled 'The last 1%', commenting on an important milestone that had just been achieved in the global attempt to eradicate polio — the official announcement that India had been declared polio free. We also remarked that although the global incidence of polio had been reduced by 99% since the concerted eradication effort began in 1988, it was the remaining 1% of cases, which had persisted since 2001, that would prove the hardest to deal with.

The latest report from the Independent Monitoring Board (IMB), the group which tracks the progress made by the Global Polio Eradication Initiative (GPEI), reflects on the efforts that have been made in 2012 to tackle that stubborn 1%. In 2011, wild poliovirus caused 620 cases of polio worldwide. In 2012, this decreased to 218 cases, a reduction of more than 60%. The latest refocused aim of the GPEI — stopping global polio transmission by the end of 2012 — is another target that has been missed. But, with a realistic acknowledgment that any hard-won gains in the fight against polio can easily be lost, the IMB remarks that the progress in 2012 has been such that, as 2013 begins, the eradication effort could be on the cusp of a golden opportunity.

The success of the campaign in India, which was maintained throughout 2012, left just three polio-endemic countries: Afghanistan, Pakistan and Nigeria. In the latest IMB report, the eradication effort in Pakistan is praised for the advances that have been made. However, two major challenges are highlighted. The first is the possibility that upcoming national elections will cause the eradication effort to lose focus and momentum. The second is security and access. In July and October 2012, two workers in the polio eradication campaign were murdered, and the IMB report comments that these deaths “lend new and unwelcome complexity to the challenge of inaccessibility”.

These words have acquired a greater resonance over the past month. In one 48-hour period in late December 2012, nine public health workers who had just completed their work as part of a polio vaccination team were murdered in coordinated attacks in Karachi (Sindh province) and Peshawar (Khyber Pakhtunkhwa province). And as the year ended, a further seven aid workers from a children's community centre were gunned down in an attack that it is speculated to have been related to the involvement of the funding charity in polio vaccination.

Although no-one has officially claimed responsibility for the attacks, there is widespread speculation of Taliban involvement. The Taliban are opposed to the national polio immunization effort, which is supported by organizations such as the WHO and UNICEF, and have helped to popularize rumours that such vaccination drives are part of Western spying or sterilization campaigns. They and other anti-government groups have caused serious disruption to vaccination efforts previously, but this most recent escalation is an extremely serious and worrying development. With trust in the vaccination programme already low, the actions of the US Central Intelligence Agency (CIA) in 2011 cannot have helped. The CIA recruited a doctor, Shakil Afridi, to run a sham hepatitis B vaccination campaign to try to gain access to the compound where it was believed Osama bin Laden was hiding, in order to obtain DNA samples. With vaccination such a vital public health tool, the exploitation of a vaccination programme in this crude way was widely condemned by commentators, who predicted there would be a backlash in local communities, and this might be reflected by recent events.

In response to the latest murders, the Pakistani government, UNICEF and the WHO have all issued strong statements of condemnation. The vaccination effort was suspended in the affected areas and has restarted in some areas with an increased security presence, but it has not been able to restart in all districts, and at this stage it is unclear when the programme will be able to catch up with all the children who have been missed. Also of major concern is the fact that the latest WHO figures show the number of measles cases in Pakistan has increased from 4,000 in 2011 to >14,000 in 2012, with 304 deaths in 2012. A major immunization campaign against measles is therefore also underway, but health workers might face an even greater struggle than before to persuade parents to get their children vaccinated.

Vaccination is one of the most cost-effective methods of reducing the burden of infectious disease. The mass vaccination campaigns that are deployed in developing countries are only possible with the involvement of a vital cadre of public health workers and volunteers. Directed attacks against these individuals are deplorable and must be condemned.