Polio Virus Resurgence in the U.S., U.K., Israel… Due to Delayed Vaccination Programs After Two Years of Pandemic and Public Hesitance Towards Vaccines.
Polio, a deadly disease that once left tens of thousands of children unable to walk each year, is making a comeback in London, New York, and Jerusalem after decades, raising concerns among experts.
This disease once instilled fear in parents worldwide during the first half of the 20th century. The virus primarily affects children under 5 years old. While the illness often presents no symptoms, some individuals may experience fever and vomiting. Approximately one in 200 cases of infection can lead to irreversible paralysis, with up to 10% of patients succumbing to the disease.
Currently, there is no effective treatment for polio; however, since scientists introduced the vaccine in the 1950s, the disease is entirely preventable. Globally, wild poliovirus has been nearly eradicated.
Afghanistan and Pakistan are currently the only countries with high transmission rates of the virus. However, this year, imported cases have been detected in Malawi and Mozambique, marking the first occurrences since 1990.
There are two main strains of the poliovirus: the wild strain and the vaccine-derived strain. The latter has been identified in London, U.K., and New York, U.S. A genetically similar virus has also been found in Jerusalem, Israel. The Global Polio Eradication Initiative (GPEI) reports that scientists are working diligently to understand the connection between these infections.
Previously, vaccine-derived poliovirus had never appeared in the aforementioned locations. It remains a threat (albeit rare) in other countries, causing annual outbreaks.
The first oral polio vaccine, developed by Albert Sabin in the 1950s, uses a live, attenuated virus. Children receiving the vaccine shed the virus in their feces within six weeks. In unvaccinated communities, this virus can reactivate and spread, undergoing genetic changes and causing paralysis in those infected.
The second type of vaccine, developed by scientist Jonas Salk, contains killed or inactivated poliovirus, which cannot cause paralysis. More than 120 countries use this vaccine, including the U.S. and U.K. It is administered via injection (in four doses), typically given to children from two to six months of age.
Children in Kandahar, Afghanistan receiving the polio vaccine on May 23. (Photo: AFP).
Experts indicate that the U.K. and U.S. no longer use live virus vaccines. However, some other countries continue to use them to prevent outbreaks. This has allowed the virus to spread globally, especially as people resume traveling after two years of COVID-19.
The patient recorded in New York was infected with a variant of the oral vaccine-derived poliovirus. The virus shares genetic similarities with strains collected from wastewater samples in London and Jerusalem.
According to Derek Ehrhardt, Director of the Polio Division at the Centers for Disease Control and Prevention (CDC) in the U.S., outbreaks of both wild and vaccine-derived viruses are concentrated in unvaccinated communities.
The United Nations notes that vaccine hesitancy is an issue that existed before the pandemic. The arrival of COVID-19 stalled global activities, causing routine vaccination programs to be delayed.
In 2020, COVID-19 caused the Global Polio Eradication Initiative’s campaigns to pause for four months, disrupting routine immunization efforts and putting over 80 million children at risk of vaccine-preventable diseases, including polio.
That year, the world recorded 1,081 cases of vaccine-derived polio, three times the number in 2019. Cases decreased in 2021 when countries resumed vaccination programs. However, the pandemic resurfaced, continuing to strain healthcare systems. By the end of 2021, wild poliovirus from Pakistan spread to Malawi. In 2022, there were 177 cases of polio globally, following significant efforts to get vaccination campaigns back on track.
However, according to scientists worldwide, including David Heymann, an epidemiologist at the London School of Hygiene & Tropical Medicine, the detection of the virus in wastewater remains a warning for parents and an important message encouraging vaccination.
