The Belgian authorities reported to the Europen Centre for Disease Prevention and Control (ECDC) that on 2 September 2014, a quantity of concentrated live poliovirus solution was accidentally released by the pharmaceutical company into a water treatment facility in Rosiéres in the southern region of Walloon. Following treatment, the liquid was released into the river Lasne, a tributary of the river Dyle, which flows into the river Escaut/Scheldt.
An investigation by the Council of Public Health concluded that the risk of infection for the population exposed to the contaminated water is extremely low due to the high level of dilution and high vaccination coverage (95%) in Belgium. Those working at the water-treatment facility were considered to be at increases risk and received polio vaccination as a precaution.
The risk assessment also concluded that beyond the junction of river Lasne with the river Dyle, the dilution of the virus in the river water reduces the risk to negligible. As a precaution, a booster dose of polio vaccine is recommended to those who have had contact with the water of river Lasne from 2 September until further notice.
Advice for Travellers
All travellers should ensure that they have completed the recommended schedule of vaccines for the UK programme, which includes 5 doses of polio vaccine.
Athough the risk is extremely low, travellers who may have been exposed to the water of river Lasne due to fishing, swimming etc, since 2 September 2014, should contact their healthcare provider to discuss the need for further vaccination against polomyelitis.