For decades, health officials around the world have used billions of drops of an oral polio vaccine in a remarkably effective campaign aimed at wiping disease.
Now, in a surprising twist in the decades-long effort to eradicate the virus, authorities in Israel, the US and UK have discovered that polio is spreading in their countries.
What was the original source of the virus? The oral Polio vaccine itself.
Scientists have known about this very rare phenomenon for a very long time. This is why some countries have switched to different polio vaccines. As the world inches closer to eradicating the disease, these incidental infections from the oral formula become more evident.
The polio cases from the oral vaccine come as the number of polio cases caused by the wild, or naturally circulating, virus plummets.
The World Health Organization and its partners have reported 396 cases of polio caused by the wild virus since 2017, compared to more than 2,600 cases linked to vaccine-derived polio.
A Columbia University professor who has studied polio eradication explained, “We are basically replacing the wild virus with vaccine derived polio, which is now leading to new outbreaks”. In my opinion, countries like the United Kingdom and the United States will be able to stop transmission quite quickly, but we also thought that about monkeypox.”
This is the first time in several years that vaccine-connected polio has been discovered in highly developed countries.
Paralyzing Polio Virus Found in Sewage
Earlier this year, Israeli officials discovered polio in an unvaccinated 3-year-old who suffered paralysis. There were a number of other children with the virus, nearly all of whom had not been vaccinated.
In June, British authorities reported finding evidence that the virus was spreading in sewage, but no people had been infected. The government announced last week that booster shots would be offered to children ages 1 to 9 in London.
Last month, New York officials revealed that an unvaccinated young adult suffered paralysis in his legs after contracting polio. The virus has also been found in New York sewers, suggesting that it is spreading. However, officials believe the state’s high vaccination rate should provide sufficient protection, so they are not planning a booster campaign.
It was revealed that all the viruses in the three countries were “vaccine-derived,” meaning that they were mutated versions of an oral vaccine virus through an inactivated polio vaccine.
Since 1988, two drops of the oral polio vaccine have been administered directly into the mouths of children because it is cheap, easy to administer, and better at protecting entire populations. The oral vaccine contains a weakened form of the live polio virus.
However, the oral vaccine can also cause polio in two to four children out of every million doses. It is necessary to receive four doses to be fully immunized. The weakened virus can mutate into a more dangerous form in rare cases, especially in places with poor sanitation.
Countries Switched to Polio Vaccine Through Injection
In most cases, these outbreaks are caused by people who have been vaccinated shedding live viruses in their feces. Viruses can spread within communities and develop into forms that can paralyze people and start epidemics over time.
To avoid such risks, most countries that eliminated polio switched to injectable vaccines decades ago; the Nordic countries and the Netherlands never used oral vaccines.
The World Health Organization’s ultimate goal is to move the entire world to polio shots once wild polio has been eradicated. Nevertheless, some scientists argue that it should be done sooner than later.
Dr. Paul Offit, director of the Children’s Hospital of Philadelphia’s Vaccine Education Center,told AP: “We probably wouldn’t have gotten on top of polio without the oral polio vaccine, but this is the price we’re paying now.” “Now we need to eliminate the oral vaccine in order to eradicate polio.”
The World Health Organization’s polio department director, Dr. Aidan O’Leary, said the discovery of the disease spreading to London and New York was a major surprise. polio vaccine CDC
He said WHO health officials have been working in Afghanistan and Pakistan to eradicate the disease, where health workers have been killed for immunizing children.
The oral polio vaccine is credited with reducing paralysis in children dramatically. Approximately 350,000 cases of wild polio were reported each year when the global eradication effort began in 1988. There have been 19 cases of wild polio this year, all in Pakistan, Afghanistan, and Mozambique.
In 2020, there were more than 1,100 cases of polio linked to the oral vaccine in dozens of countries. So far this year there have been approximately 200 cases.
The WHO last year also began using a newer polio vaccine containing a live, weakened virus that scientists believe is less likely to mutate and become dangerous. There are, however, limited supplies.
According to experts, more vaccination is needed in Britain, the U.S. and Israel to end polio. The WHO worries it could be challenging in the post COVID-19 era.