The World Health Organization (WHO) has confirmed that 11 new cases of polio in five African countries including Nigeria, Congo and Angola were caused by a mutation in polio vaccinations.
While Western countries use an injectable form of the polio vaccine, containing an inactivated form of the virus, those in non-Western countries tend to use an oral version that contains a live, attenuated virus due to its relatively low cost and ease of administration.
Effective in most cases, occasionally, the live virus vaccine has been known to mutate into a form capable of infecting individuals and potentially sparking a new outbreak. Although this type, known as Type 2, was eliminated years ago in the wild, all current cases of vaccine-derived polio cases have been sparked by this kind.
A highly infectious disease spread by contaminated food and water, it usually affects children under 5 years old. In total, approximately 1 in every 200 infections leads to paralysis. Among those, a small number die as their respiratory muscles collapse and they are unable to breathe.
Already, seven other countries in Africa have reported similar outbreaks, with cases having also been reported in Asia, including in the two countries where polio is still endemic: Afghanistan and Pakistan.
Barbara Fisher, co-founder and president of the National Vaccine Information Center, said, “In impoverished communities with substandard sanitation and living conditions, vaccine strain poliovirus can contaminate water sources used for bathing and drinking, which can lead to more cases of vaccine strain polio paralysis...Until polio eradication campaigns stop using live oral polio vaccine, the vaccine strain polio virus will continue to cripple children and adults.”
So far this year, 157 vaccine-derived cases of polio have been reported from around the world, significantly higher than the 107 cases of poliovirus derived from wild strains. The Independent Monitoring Board, a group set up by WHO to assess the eradication of polio has thus said that this strain of vaccine-derived polio is “spreading uncontrolled in West Africa, bursting geographical boundaries and raising fundamental questions and challenges for the whole eradication process.”
A concern worldwide, global leaders convened last week at Reaching the Last Mile (RLM) Forum in Abu Dhabi, where they pledged $2.6 billion to eradicate the disease.
Sources: Washington Times, NPR, Dawn and The Scientist
