Is the fight against polio more important than ever? Statement of the Society of Virology

Is the fight against polio more important than ever? Statement of the Society of Virology

In a letter to the German Federal Ministry for Economic Cooperation and Development (BMZ), the National Commission for Polio Eradication (NCC) criticizes the planned budget cut for the Global Polio Eradication Initiative (GPEI) for 2025 and points out the urgency of continuing the fight against polio.

The Society of Virology also considers the planned budget cut to be problematic, as the current global crisis situation poses a major risk of a resurgence of poliomyelitis ("polio") in regions that have been considered poliovirus-free for many years. As a result of global travel, poliovirus infections can also be introduced here undetected within a very short time by asymptomatically infected people and, if the virus is transmitted to inadequately vaccinated people, can lead to serious illness, lifelong disabilities and death.

According to Unicef, the number of children suffering from polio in crisis countries has doubled in the last five years, which was recently highlighted by the first case of polio in Gaza in around 25 years. Polioviruses are highly infectious and spread primarily via fecal-oral transmission. Such transmissions are facilitated in particular by poor hygienic conditions in regions with limited healthcare or in war zones. Major outbreaks can therefore only be prevented if infections are detected early and isolated as quickly as possible through appropriate hygiene management and if there is sufficient vaccination protection among the population (95% vaccination rate among children). Both are only possible under very difficult conditions, especially in crisis regions, and require special programs such as the GPEI and corresponding financial support. Only in this way was it possible to vaccinate around half a million children against poliovirus during temporary ceasefires in Gaza using socio-political influence and a major vaccination campaign in order to reduce the vaccination gaps. However, these vaccination gaps have by no means been completely closed here, nor in many other crisis regions in Africa and Asia.

The success of the global vaccination campaign is demonstrated by the fact that of the three existing polioviruses (types 1,2,3), only the wild-type virus of type 1 is still circulating, and that in only two countries worldwide. However, insufficient vaccination rates carry the risk of re-importation and re-circulation of polioviruses in regions where the virus had already been eliminated. To break chains of infection, effective protection against the initial infection is necessary, which is possible through vaccination with live-attenuated vaccine viruses.

In rare cases, however, live-attenuated vaccine viruses can mutate back into the disease-causing virus. These vaccine-derived polioviruses are excreted like wild-type viruses and can spread among unvaccinated people. They can trigger poliomyelitis in a similar way to wild-type viruses, as has been proven in the child from Gaza and other cases. According to the WHO, 3,390 such cases were registered worldwide between 2020 and 2024. Considering that less than 1% of all infected people develop poliomyelitis with paralysis at all, this is an indication that the number of cases of infection is probably already significantly higher due to a lack of herd immunity in these regions, which underlines the urgency of the vaccination campaigns.

In many industrialized countries where polio is considered to have been eliminated, including Germany, inactivated vaccines are used, which can reliably prevent disease but not the actual infection and transmission of the virus. As a result, polioviruses could spread again among unvaccinated people if vaccination rates fall.

According to the NCC, vaccine-derived polioviruses are currently detected in 41 countries worldwide, highlighting the need for global surveillance programs (e.g. via poliovirus detection in wastewater) to identify risks at an early stage.

Therefore, the successes achieved so far in polio eradication are still on shaky ground and we must not let up in our efforts in these times. The past has shown that making up for setbacks requires much greater efforts than a consistent continuation of the current program.

The Immunization Commission and the Executive Board of the GfV

Click here to access the PDF version of the statement.