It has been a difficult year for the global campaign to eradicate polio. In August, two new wild polio cases were reported in Nigeria, which accounted for half of the global count in 2012 yet had not recorded a single wild polio incident since July 2014. It was a year away from being certified polio-free by the World Health Organization.

Despite this, polio now remains endemic in only three countries: Afghanistan, Pakistan, and Nigeria, with a total of 27 wild polio virus cases between them. Today, Type 1 poliovirus (WPV1)—always the most common—is the only strain still in existence. Type 2 (WPV2) was eradicated in 1999, with the last case detected in Aligarh, India. Type 3 (WPV3), the deadliest and most difficult to detect, has not been recorded since a case reported by Nigeria in November 2012.

Since 1988, polio cases have decreased by more than 99% from an estimated 350,000 cases to 27 cases in 2016 from just three countries. The world lies at the brink of eradicating the virus once and for all, but as long as even a single child remains infected, the virus poses a threat to the international community.

As this community marks World Polio Day, it is important to remember that polio is preventable, but not curable. While remarkable progress has been achieved, tremendous challenges still remain. With polio cases on the decline, just last year, the poliovirus did something unique. While WPV2 had been eradicated in 1999, cases of vaccine-associated polio paralysis (predominantly of type 2) started emerging in the Dominican Republic and Haiti and have occurred in 16 countries since. The oral polio vaccine (OPV) includes all three strains of the virus to build immunity. The emerging challenge has become not only to eradicate wild polio virus but also the virus that can derive from use of the vaccine.

A historic global switch undertaken by 155 countries in April 2016 to a “bivalent” rather than “trivalent” OPV for routine immunization has attempted to address one of the pressing challenges faced by the WHO and the Global Polio Eradication Initiative. The bivalent vaccine is estimated to be 30% times more effective and only contains vaccine against poliovirus types 1 and 3, removing the type 2 component that has been responsible for 80% of the vaccine-derived outbreak in the Caribbean.

Despite the humanitarian emergency in Nigeria due to growing violence, the massive response effort currently underway in the Lake Chad region is yet another indication that nothing is going to detract from Africa’s goal of becoming polio-free. Countries across the continent have worked too hard to stop short of eradicating the virus. In the meantime, the 7 million people in the area lacking access to basic health services and its mass movements of people present a great risk of polio being exported.

Polio responses in such situations need to be folded into broader humanitarian responses, in which children and families are provided much more than just the polio vaccine to start building immunity. This includes food, water, nutrition supplements, and basic healthcare. The same model is used in polio responses within the Middle East and is gradually spreading to Afghanistan and Pakistan also.

This strategy also makes sense from a security and political standpoint, most significantly in Afghanistan and Pakistan. In my work in the latter country, I have met with scores of lady health workers, campaign organizers, government and WHO officials, and, most importantly, families that refuse the virus knowing fully well that their children run the risk of paralysis.

With exceptions, in areas of the Punjab region, cases of refusal often cite concern over the “halal” nature of the vaccine, driven by rumors that it sterilizes children. In Sindh, families abuse and shun health workers for bringing them vaccines instead of food, water, and basic supplies. Finally, a few recent cases in Khyber Pakhtunkhwa have emerged where families are afraid to let health workers administer the vaccine and mark their houses in medical history reporting, thinking instead that they are being marked for US drone strikes. Folding polio vaccines under the ambit of providing broader basic healthcare and humanitarian supplies then is not only operationally beneficial but may also be more cost-effective in the long run.

The concern about drone strikes and CIA involvement in the polio campaign in Pakistan is not new. In January 2011, Dr. Shakil Afridi, a health professional ran a fake Hepatitis B vaccination campaign rumored to have helped the CIA locate Osama bin Laden’s compound in Abbottabad, Pakistan. Afridi’s story is a reminder of what happens when health professionals are too closely involved with intelligence operations. Security challenges were amplified when Afridi’s work was presented as a fake polio vaccination campaign, dealing a massive blow to eradication efforts and generating deep suspicion, anger, and mistrust of health workers throughout Pakistan. In July 2012, the Taliban issued a polio vaccination ban in Waziristan, thereby depriving close to 290,000 children from receiving a single dose of the vaccine. Since July 2012, 86 health workers and security personnel have been targeted and killed by militants, while almost 72 have been injured.

However, Pakistan’s security concerns are not unique. Nigeria too witnessed consistent attacks on its health workers by Boko Haram and vaccination bans issued by religious clerics in 2003 halted campaigns in the north of the country. Nonetheless, through concerted government efforts and a coordinated approach with all stakeholders from women to religious clerics and the army to health workers, the country was able to stamp out polio in 2014.

Polio cases have seen a dramatic decline in Pakistan and Afghanistan. In 2014, Pakistan broke the global record by recording 306 polio cases; 85% of the global count. Afghanistan, by comparison, recorded 28 cases (an estimated 19 cases of were exported from Pakistan through movement of people) while Nigeria recorded six. For this year, currently the count stands at 15 in Pakistan, eight in Afghanistan, and four in Nigeria.

The Pakistan Army has been paramount in helping reduce the number of polio cases within the country. A military operation in tribal areas has not only helped health officials to vaccinate hundreds of thousands of children for the first time but also allowed the army to set up polio vaccination camps at border areas, ensuring that children and families fleeing to other parts of the country receive the vaccine and do not become carriers. Polio reservoirs in Karachi, the Quetta block, and Peshawar remain problematic and any negligence in vaccination campaigns could be detrimental to the global fight. Strengthening coordination with international agencies as well as local community organizations is thus of paramount importance.

Most of Afghanistan’s cases are in the east due to a deteriorating security situation, which threatens both countries owing to movement of people across the porous border. The number of missed children in inaccessible areas has risen to 130,000 (May 2016) and any gains in fragile zones remain threatened because of the shifting security dynamic. Most importantly, the Afghan polio eradication program continues to employ male vaccinators from outside instead of engaging female community health workers to administer the vaccine. Lessons learned from global polio campaigns around the world show tremendous progress in increasing accessibility and trust-building when the vaccinators are women and are recognized members of the local community.

Joint cooperation between the governments such as those in Afghanistan and Pakistan is far below the minimum required to interrupt polio transmission, which is problematically reflected in border area and high-risk zones that have consistently tested positive for the virus. Under the circumstances, a misplaced Afghan reliance on Pakistan to first end polio transmission may further delay any possible progress.

The re-emergence of polio cases in Nigeria (where the virus was circulating undetected for two years) and Bannu, Pakistan (which was believed to be well protected) are reminders that eradication programs need to be robust and resilient against reemergence. Rapid emergency responses and quick decision-making are critical in containing any new cases.

Arsla Jawaid works with the Center for Peace Operations at the International Peace Institute. @arslajawaid