Polioviruses in German wastewater samples: What parents should know
- Johanna
- Aug 30
- 5 min read
Updated: Aug 31
Since the end of November 2024, traces of polioviruses have been found in wastewater in several German cities, including Munich, Bonn, Cologne, Hamburg, and later in Dresden, Mainz, and Stuttgart. These are known as vaccine-derived polioviruses, which originally come from attenuated oral vaccines.
The Robert Koch Institute (RKI) now considers that local transmission of these viruses is at least possible. However, no cases of illness have been reported so far.
What is polio?
Poliomyelitis, better known as "infantile paralysis," is a highly contagious viral infection for which no specific treatment currently exists. The poliovirus is primarily transmitted through the fecal-oral route. This means that if the virus enters the mouth due to poor hygiene, contaminated water, or contaminated food, an infection can occur.
Approximately 25 percent of infected people develop flu-like symptoms. What's particularly dangerous is that many infected individuals exhibit no or only mild symptoms, yet they can still excrete and transmit the virus. Therefore, direct transmission from person to person is possible without immediate detection n
1 to 5 percent develop meningitis.
Very rarely, spinal cord lesions occur, and in these cases, paralysis is a risk. Inadequately protected individuals can develop permanent paralysis, which is especially dangerous if the respiratory muscles are affected.
In the past, there were thousands of cases per year in Germany alone, resulting in hundreds of deaths. Thanks to vaccinations, polio has virtually disappeared today, but the risk remains as long as the virus continues to circulate elsewhere.
Danger to children and adults
Children who are fully immunized usually enjoy robust protection.
Unvaccinated or incompletely vaccinated adults and children are particularly at risk of developing severe cases.
Adults usually benefit from earlier vaccinations, but in cases of uncertainty, travel to risk areas, or immunodeficiency, they should check their vaccination status and, if necessary, have it updated to the level recommended by the STIKO.
How do polio viruses get into wastewater?
Since 1998, Germany has used only the inactivated vaccine (IPV via injection), which does not contain live viruses. Therefore, it cannot enter wastewater. The oral live vaccine (OPV) is no longer used in Germany and other countries that are polio-free.
However, OPV is still used in other countries. After vaccination, weakened viruses are excreted in the stool and thus enter wastewater. The vaccinated person remains healthy. According to UNICEF, in 2023, around 143 countries and regions still used the oral polio vaccine (OPV) as an integral part of their routine programs. OPV is used primarily in places where polio is still prevalent or where vaccination rates are low.
In rare cases, these vaccine viruses can mutate and become dangerous again. This is referred to as vaccine-derived polioviruses. The polioviruses found in German wastewater originate from people returning from or moving to regions where OPV vaccinations are available.
However, there is no cause for concern for vaccinated children and adults.
Can water filters filter out polio viruses?
You can still drink tap water in Germany without any problems, even considering the recent detection of vaccine-derived polioviruses in wastewater.
Drinking water in Germany is strictly monitored and treated.
There is no direct contact between wastewater in which polioviruses have been detected and drinking water.
Waterworks implement multiple safety measures, such as filtration and disinfection, to ensure that pathogens are reliably removed.
Polioviruses are very small —about 27 nanometers in size. Standard household water filters (e.g., activated carbon filters, table filters, simple camping filters) are unable to reliably filter out viruses of this size. While they improve taste and remove bacteria or particles, they are not reliable against viruses.
Special filters: Only high-performance filters with extremely fine membranes (e.g., ultrafiltration or reverse osmosis with pore sizes below 0.01 micrometers) can retain viruses like polio to any significant extent. However, such systems are usually expensive and require regular maintenance.
Boiling: Polio viruses are sensitive to heat. Boiling water for at least one minute reliably destroys the viruses. This is the safest and most practical method if there is any doubt about the quality of drinking water.
Disinfection with chlorine: Adequate chlorination of water can also render polioviruses harmless. Therefore, drinking water disinfection is a crucial protective measure in many countries.
Regular household water filters are not sufficient to safely remove polioviruses. Those traveling or living in regions where polio is still prevalent or where the drinking water supply is unsafe should use boiled or commercially bottled water. The best protection for children and adults is vaccination against polioviruses.
Vaccination protection – what parents should know
The Stiko recommends:
Primary immunization in infancy with three IPV vaccinations in the first year of life.
Refresher between 9 and 16 years.
The inactivated IPV vaccine provides very reliable protection against disease, although infection and transmission cannot be ruled out in every case.
In Germany, parents can decide for themselves which vaccinations their child receives. The exception is the measles vaccination, which is mandatory upon entry into kindergarten/daycare.
Current data from the Robert Koch Institute (RKI) shows that the STIKO recommendation is often not followed in a timely manner:
More than half a million children in a given year are not fully vaccinated by their first birthday.
Even by age two, over 180,000 children lack complete protection.
The third vaccination, in particular, is often given too late in many areas.
Additionally, there are significant regional differences: In some districts, the vaccination rate among two-year-olds drops below 60 percent.
This leaves a significant number of children vulnerable.
Polio vaccination in adults
Anyone who has received primary immunization as a child and a booster in adolescence is generally protected from disease for life. Routine booster vaccination is not necessary.
An additional vaccination is recommended for adults if
they are unvaccinated or incompletely vaccinated,
their vaccination status is unclear,
For longer stays (over four weeks) or trips to unstable regions, the Federal Foreign Office recommends a booster if the last vaccination was more than ten years ago.
or they may come into contact with polioviruses in their professional activities (e.g. healthcare, laboratory, wastewater sampling).
Key messages for parents
Polio from wastewater is an important warning signal to check vaccination status; if it is complete, then there is no reason to panic.
When traveling to high-risk areas, make sure you have valid polio vaccinations.
The greatest risk arises when children or adults are not fully vaccinated.
Status: 08/2025
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