by LONDON (AP) – The child in Gaza who was recently paralyzed by polio was infected with a mutated strain of the virus that vaccinated people shed in their waste, according to scientists who say the case is the result of “failed unqualified” community. health policy.
The infection, which marked the first detection of polio in the war-torn Palestinian territory for more than 25 years, paralyzed the lower part of one leg in the unvaccinated 10-month-old child. The baby boy was one of hundreds of thousands of children who missed out on vaccinations because of the fighting between Israel and Hamas.
Scientists monitoring polio outbreaks said the child’s illness showed that a global effort by the World Health Organization and its partners had failed to address serious problems in their highly successful eradication campaign, ending the almost a highly contagious disease. Separately, a draft report by experts deemed the WHO effort a failure and a “serious setback.”
The polio strain in question originated from a weakened virus that was originally part of the oral vaccine that was used to prevent paralysis in millions of children around the world. But that virus was removed from the vaccine in 2016 in hopes of preventing vaccine-derived outbreaks.
The public health authorities knew that decision would leave people unprotected against that particular strain, but they thought they had a plan to quickly contain any outbreaks. Instead, the move resulted in a surge of thousands of cases.
“It was a terrible strategy,” said Columbia University virologist Vincent Racaniello, who was not involved with the report or the WHO. “The decision to switch vaccines was based on a wrong assumption, and the result now is that we have more polio and more paralyzed children.”
A draft copy of the report commissioned by the WHO and independent experts said the plan underestimated the pressure on the environment and overestimated how well officials would be able to squash outbreaks.
The plan led to vaccine-linked polio outbreaks in 43 countries that paralyzed more than 3,300 children, according to the report.
Even before the Gaza case was discovered, officials reviewing the initiative to tinker with the vaccine concluded that “the worst-case scenario has emerged,” the report said.
The report has not yet been published, and some changes are likely to be made before the final version is released next month, the WHO said.
The strain that infected the child in Gaza had died out in the environment and evolved into a version capable of starting outbreaks. It was traced to polio viruses that spread last year in Egypt, according to a genetic sequence, the WHO said.
In 2022, vaccine-linked polio viruses were found to be circulating in Britain, Israel and the United States, where an unvaccinated man in New York was paralyzed.
Scientists are now concerned that the emergence of polio in a war zone with an under-immunized population could further spread.
Racaniello said the failure to carefully track polio and protect children from the strain of the vaccine had dire consequences.
“Only about 1% of polio cases are symptomatic, so 99% of infections are spreading the disease silently,” he said.
The oral polio vaccine, which contains a live attenuated virus, was withdrawn in the United States in 2000. Doctors continued to vaccinate children and eventually moved to an injectable vaccine, which uses a dead virus and does not carry the risk of polio . in human waste. Such residual-carrying virus may change into a form that triggers outbreaks in unvaccinated people.
The report’s authors faulted WHO leaders and its partners, saying they were unable or unwilling to “recognize the evolving gravity of the problem and take corrective action.”
WHO spokesman Oliver Rosenbauer admitted that the vaccine strategy “increased” the risk of vaccine-related epidemics.
He said in an email that the immunization “has not been implemented in a way to quickly stop outbreaks or to prevent new strains from emerging.” Rosenbauer said failure to meet vaccination targets poses the greatest risk of allowing vaccine-linked viruses to emerge.
“You have to contact the children with the vaccines … no matter which vaccines are used,” he said.
The WHO estimates that 95% of the population needs to be immunized against polio to stop outbreaks. The UN health agency said only about 90% of Gaza’s population had been vaccinated earlier this year.
To try to stop polio in Gaza and the wider region, the WHO and its partners plan two rounds of vaccination campaigns later this week and next month, with the aim of covering 640,000 children. Authorities will use a newer version of the oral polio vaccine that targets the problematic strain. The live attenuated virus in the new vaccine is less likely to cause vaccine-derived outbreaks, but they are still possible.
Racaniello said it was “unethical” that the WHO and its partners were using an unlicensed vaccine in rich countries precisely because it could increase the risk of polio in unvaccinated children.
The oral polio vaccine, which has reduced global infections by more than 99%, is easy to make and distribute. Children need only two drops per dose which can be administered by volunteers. The oral vaccine is better at stopping transmission than the injectable version, and is cheaper and easier to give.
But as the number of polio cases caused by the wild virus has fallen in recent years, health officials have struggled to contain the growing spread of vaccine-related cases, which now account for the majority of polio infections in more more than a dozen countries, i. As well as Afghanistan and Pakistan, where the transmission of the wild virus has never been stopped.
“This is the result of the Faustian bargain we made when we decided to use the oral polio vaccine, said Dr. Paul Offit, director of the Vaccine Education Center at Philadelphia University. we need to stop using the vaccine with live (weakened) virus.
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The Associated Press Health and Science Section is supported by the Howard Hughes Medical Institute Science and Media Education Group. The AP is solely responsible for all matters.
