H1N1 virus and wastewater
Assessment of the health risks to workers associated with the presence of the Influenza A (H1N1) 2009 pandemic virus in wastewater.
The World Health Organization declared the occurrence of a human influenza pandemic due to the Influenza A (H1N1) 2009 virus on 11 June 2009. France had been preparing for this eventuality for several years, particularly through the French plan to prevent and control an influenza pandemic. At that time, the Agency was requested to assess the risks to workers, associated with the presence of the InfluenzaA (H1N1)2009 pandemic virus in wastewater.
In 2006, the French Ministry of Health formally requested the Agency to assess the health risks for the general population and workers, associated with the presence of the Influenza virus in aqueous effluents and surface water. Following the emergence of the Influenza A (H1N1) 2009 virus in March 2009, on 9 June 2009 the French Ministry of Health urgently requested the Agency to assess the health risks to workers in sewage and wastewater treatment plants, in the event of contamination of wastewater by the Influenza A (H1N1) 2009 virus.
In the Agency’s 2006 assessment, it studied in particular the hypothesis of wastewater contamination by the avian Influenza virus sub-type H5N1 and considered it to be unlikely. However, the Agency recommended that this opinion be reconsidered if a new virus pandemic emerged.
In 2009 the Agency estimated as unlikely or negligible the risk of the Influenza A (H1N1) 2009 virus being transmitted to sewage workers (sewage and wastewater treatment plants) through wastewater, compared to the risk of classical inter-human contamination (coughs, sneezes, etc.) that remains predominant. Consequently, the Agency recommended that workers who may come into contact with wastewater apply the usual measures for protection and hygiene, and underlined that there was no advantage in recommending that they wear a FFP2 mask. In fact, the Agency considered that this mask might, in certain situations, lead to a delay putting on the necessary protective mask if toxic gas was detected in the sewers.