To eradicate polio in its last remaining strongholds, primarily in underdeveloped, politically unstable regions of the world, global health officials have used billions of drops of an oral vaccine in a highly effective campaign. Authorities in Jerusalem, New York, and London have discovered signs of polio spreading, in a shocking turn of events in the long-running campaign to eradicate the virus. What was the virus’s original origin? The actual oral vaccination!
Scientists are well aware of this incredibly unusual occurrence. As a result, some countries have switched to different polio vaccines. However, as the world approaches eradication and the number of cases caused by the wild, or naturally circulating, virus declines, these incidental infections from the oral formula become more visible.
In contrast to the over 2,600 polio cases linked to the oral vaccine since 2017, the World Health Organization and its partners report only 396 cases of polio caused by the wild virus. ‘ We’re basically replacing the wild virus with the virus in the vaccine, which is now causing new outbreaks,’ said Scott Barrett, a polio eradication expert at Columbia University. ‘I believe that countries like the United Kingdom and the United States will be able to stop transmission fairly quickly, but we also thought that about monkeypox’.
The most recent cases represent the vaccine-associated polio virus’s first appearance in developed countries in several years. Israeli authorities discovered polio in a 3-year-old boy who had not received the vaccine and was paralyzed earlier this year. Other children, almost all of whom had not been immunized, were found to have the virus but no symptoms.
Although no human illnesses were discovered, British authorities announced in June that they had discovered evidence of the virus spreading in sewage. Last week, the government announced that all children between the ages of one and nine in London would receive a booster vaccination. A young adult who was not immunized and contracted polio in the United States eventually developed paralysis in his legs, according to New York officials. The virus was also discovered in New York’s sewers, indicating that it is spreading.
However, officials stated that they do not intend to launch a booster campaign because they believe that the state’s high vaccination rate should provide adequate defence. Genetic tests revealed that the viruses in the three countries were all ‘vaccine-derived,’ meaning they were mutated variations of a virus that originated in the oral vaccine. Since 1988, the oral vaccination in question has been used to protect entire communities where polio is on the rise because it is less expensive and easier to administer (two drops are placed right into the mouths of children). The live virus is present, albeit in an attenuated form.
These outbreaks are usually caused by vaccinated people passing the live virus from the vaccine in their faeces. From there, the disease can spread among the local population and eventually evolve into a form that can paralyse people and cause new epidemics.
To avoid these risks, several polio-free countries switched decades ago to injectable vaccines containing a dead virus; the Nordic countries and the Netherlands never used the oral vaccine. When wild polio is eradicated, the ultimate goal is to transition the entire world to vaccinations, though some scientists believe this should happen sooner.
‘We probably could never have gotten on top of polio in the developing world without the (oral polio vaccine), but this is the price we’re now paying,’ said Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia. ‘ The only way to eliminate polio is to stop using the oral vaccine’.
According to Aidan O’Leary, director of the WHO’s polio department, the discovery of polio spreading in London and New York was a ‘major surprise,’ as officials had been focusing on eliminating the disease in Afghanistan and Pakistan, where medical personnel has been killed for immunising children and access to some areas has been difficult.
Despite this, O’Leary expressed confidence that Israel, the United Kingdom, and the United States will quickly contain their recently discovered breakouts. The oral vaccine is credited with significantly lowering the number of children who suffer from polio-related paralysis. When the global eradication effort began in 1988, there were approximately 350,000 cases of wild polio per year. So far this year, 19 cases of wild polio have been reported in Pakistan, Afghanistan, and Mozambique.
At their peak in 2020, more than 1,100 cases of polio associated with the vaccine were reported from various countries. It has since dropped to around 200 this year. Last year, the WHO and its partners began using a newer oral polio vaccine. It contains a live but weakened virus, which researchers believe has a lower chance of mutating into a dangerous version. However, supply is restricted. Experts agree that more immunisation is needed to eradicate polio in Israel, the United Kingdom, and the United States. Barrett of Columbia University is concerned that this might be difficult in the COVID-19 era.
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