Laos sees first case of polio for more than 20 years, as virus re-emerges around world

The World Health Organisation has reported that an eight-year-old boy in Laos became paralysed from the poliovirus in early September and died five days later.

The case is believed to be the first infection in the country since 1993 and is part of an alarming reemergence of polio around the world in recent months. Ukraine and Mali - two other countries where the virus was thought to have been wiped out - also reported new cases of polio.

WHO officials said that genetic sequence showed that the virus was derived from an oral vaccine and that it might have been circulating in Laos’ Bolikhamxay Province for more than two years. The oral polio vaccine contains a weakened virus, and when a child is immunised the virus replicates in the intestine and is excreted by the individual. In places where there are sanitation issues, this virus can infect others in the community before dying out.

When a population is seriously under-immunised this virus can circulate for a long time and mutate into a form that can paralyse. The district where the child lived in Laos has chronically low immunisation rates: 40 per cent to 66 per cent between 2009 and 2014 and 44 per cent in 2015 to date for three doses of oral polio vaccine.

Before this most recent infection, Laos had been polio-free since 1993, when its last case of indigenous wild poliovirus was reported.

The WHO said that the country’s ministry of health, in conduction with the WHO, UNICEF and the US Centres for Disease Control and Prevention, sent a team to the boy’s village to collect stool samples and that they have activated an emergency immunisation effort for the province and several adjacent provinces.