For the first part of the 20th century, polio terrified parents all across the world. It primarily affects children under the age of five and is frequently asymptomatic, though it can occasionally bring on symptoms including fever and vomiting.
One in 200 infections results in irreversible paralysis, and up to 10% of those individuals pass afterward. Although there is no treatment for polio, it is completely avoidable thanks to a vaccination developed in the 1950s. The disease's wild form has all but vanished worldwide.
The two remaining endemic nations are Afghanistan and Pakistan. The highly contagious disease is carried mostly through contact with feces. However, this year also saw the discovery of imported cases in Malawi and Mozambique, the first in those nations since the 1990s.
Poliovirus comes in two primary varieties. There are a few isolated instances of the so-called "vaccine-derived polio" in addition to the wild-type described above.
It is this second type that has been found in wastewater in the American city of New York as well as in London, the capital of the United Kingdom, where one paralysis case has been reported. According to the Global Polio Eradication Initiative (GPEI), a genetically similar virus has also been discovered in Jerusalem, Israel, and researchers are attempting to determine how the two are related.
While vaccine-derived polio is virtually unknown in the aforementioned regions, it is a known, albeit infrequent, concern in other nations and is responsible for outbreaks every year, including 415 cases in Nigeria in 2021.
It results from the administration of an oral polio vaccine that contains a live virus that has been attenuated. Following vaccination, children continue to pass the virus in their feces for a few weeks. This can then spread and mutate back into a dangerous variant of the virus in areas with low vaccination rates.
While some nations, including the United States and Britain, no longer use this live vaccination to prevent outbreaks, others do, scientists said. This allows for worldwide spread, especially since individuals started traveling again after COVID-19.
Around 1,081 cases of polio caused by vaccination were reported in 2020, nearly three times as many as in 2019. Following significant attempts to restart polio immunization campaigns, there have been 177 cases so far in 2022.
Scientists from all across the world, including David Heymann, an epidemiologist at the London School of Hygiene and Tropical Medicine, said that the wastewater findings are still a wake-up call for parents with one important message: Protect children by having them immunized.
