(CNN)Progress has stalled in ridding the world of polio. An emergency committee of the World Health Organization unanimously agreed Friday to continue to designate the paralyzing disease a "Public Health Emergency of International Concern." WHO originally designated polio in this way in 2014, deeming it a health threat serious enough to endanger communities worldwide.
This year, WHO has recorded 27 cases of wild poliovirus worldwide, compared with 22 total cases last year. Though the small number of cases may appear insignificant, the committee said the trend is noteworthy because it shows stagnation.
Poliomyelitis, which is transmitted person-to-person through the fecal-oral route or through contaminated food, mainly affects young children. Fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs are symptoms of the disease, which also can cause permanent paralysis. There is no cure for polio, and it can be prevented only by vaccine.
The Global Polio Eradication Initiative, a partnership of WHO, UNICEF, the US Centers for Disease Control and Prevention, Rotary International and the Bill & Melinda Gates Foundation, was initiated 30 years ago. In 1988, polio was endemic in 125 countries and sickened 350,000 children annually, but as a result of the public-private initiative, polio is now endemic in just three nations -- Afghanistan, Nigeria and Pakistan -- while total cases have dropped more than 99%, according to WHO.
On Friday, the WHO emergency committee praised the "continued high level commitment seen in Afghanistan and Pakistan," yet it noted that the number of wild polio cases in Afghanistan has almost doubled in 2018, with 19 cases reported this year, compared with 10 at the same time last year. In Pakistan, the 2018 polio situation is stagnant compared with last year, while in Nigeria, more than two years have passed since the last case of poliovirus was detected, the committee noted.
In 2016, Nigeria reported a case of wild poliovirus after two years with none; WHO committee members did not speculate when the nation, which recorded 27 cases of vaccine-derived polio this year, would be declared free of the disease.
Additionally, outbreaks of various strains of vaccine-derived polio in Somalia, Kenya, Democratic Republic of Congo, Niger, Papua New Guinea and Somalia continue to be of "major concern," the committee said, given that these viruses have rarely spread across borders.
Vaccine-derived polio occurs when the weakened vaccine virus in the oral polio vaccine is excreted and then spreads in the community, according to WHO. The solution for stopping this type of polio is the same as for all polio outbreaks, according to WHO: Every child must be immunized several times with the oral vaccine.
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Many countries remain vulnerable, according to WHO. "Gaps in population immunity," including in Western nations, would allow the disease to be imported into a nation where polio no longer exists.
If polio eradication around the globe is not accomplished in the next couple of years, a resurgence of the disease is likely -- much like what is occurring now with measles, the WHO emergency committee said. On Thursday, WHO reported that measles cases, which occurred in all world regions, spiked in 2017 and led to an estimated 110,000 deaths.
