Type 2 polioviruses (VDPV2) have been detected in wastewater from densely populated urban areas, including Poland, Spain, Germany, Finland, and the United Kingdom. Although poliovirus is no longer actively circulating in these countries and no cases of polio have been reported, these detections represent an unusual and concerning situation. Santé publique France is monitoring the situation closely, as these events indicate a risk of reintroduction and continued circulation of the virus within Europe until the global eradication goal is achieved.

What is currently known about the circulation of polioviruses in Europe?

In recent months, polioviruses derived from type 2 vaccine-derived poliovirus (VDPV2) strains have been detected in wastewater samples collected in various cities across Europe in five different countries: Barcelona (Spain), Warsaw and Rzeszów (Poland), Tampere (Finland), as well as several cities in Germany and the United Kingdom.

These polioviruses are genetically linked to a strain that emerged in Nigeria several years ago and circulated primarily in North and West African countries until 2024. While isolated detections may be observed during wastewater surveillance programs, their current frequency and extent suggest a potential risk of transmission within communities with low vaccination coverage. To date, no local circulation has been confirmed, and no cases of paralysis have been observed. According to international and European authorities, the most likely explanation for these detections is repeated introductions of polioviruses from regions where this cVDPV2 is currently circulating.

The Global Context: A Challenge for Polio Eradication

Although Europe has been officially polio-free since 2002, the risk of poliovirus introduction remains as long as global eradication has not been achieved. Outbreaks of wild poliovirus persist in some regions of the world, such as Pakistan and Afghanistan. Furthermore, type 2 VDPVs are circulating epidemically in many countries worldwide (Yemen, Chad, Nigeria, DRC, Ethiopia).

In recent years, cases of paralysis caused by vaccine-derived polioviruses (cVDPV type 2 or 3) were detected in Ukraine in 2021–2022, in Israel in 2022, and in Gaza in 2024, underscoring the need to maintain enhanced surveillance and launch vaccination campaigns in response to these alerts. A case of paralytic polio caused by VDPV2 was reported in July 2022 in New York, and genetically similar VDPV2 was detected in wastewater in London, New York County, and Jerusalem that same year, demonstrating the still-real risk of this virus circulating and the possibility of polio cases occurring, even in countries that have been polio-free for many years.

Low risk of poliovirus in France, but vigilance must be maintained

In France, surveillance for poliovirus in wastewater ceased in 2018 due to the rarity of virus detections and an already very high three-dose vaccination coverage rate, which now stands at 96% among 24-month-old infants born in 2020. The ANRS-MIE research program launched in 2023–2024 aims to pave the way for the resumption of routine poliovirus surveillance in France. This ongoing work led to the detection of type 3 VDPV in French Guiana in 2024.

Health authorities in France remain vigilant regarding the risk of introduction and spread of vaccine-derived polioviruses linked to individuals arriving from countries where the oral polio vaccine is still in use. This risk exists within the country, as recently demonstrated by the detection of type 3 VDPV circulating in French Guiana, particularly in areas or among certain population groups with limited use of the healthcare system and access to vaccination (migrants, socially disadvantaged populations, immigrant populations, etc.), where vaccination coverage is lower. Thus, the priority remains maintaining a high (>90%) and consistent vaccination rate by reducing social and regional health inequalities in order to prevent any risk of a resurgence of the disease. Indeed, there is no treatment for polio. The main measures rely on hygiene and vaccination.