LONDON (news agencies) — The baby 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 “an unqualified failure” of public health policy.
The infection, which marked the first detection of polio in the war-torn Palestinian territory in 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 vaccinations because of the fighting between Israel and Hamas.
Scientists who have been monitoring polio outbreaks said the baby’s illness showed the failures of a global effort by the World Health Organization and its partners to fix serious problems in their otherwise largely successful eradication campaign, which has nearly wiped out the highly infectious disease. Separately, a draft report by experts deemed the WHO effort a failure and “a severe setback.”
The polio strain in question evolved from a weakened virus that was originally part of an oral vaccine credited with preventing millions of children worldwide from being paralyzed. But that virus was removed from the vaccine in 2016 in hopes of preventing vaccine-derived outbreaks.
Public health authorities knew that decision would leave people unprotected against that particular strain, but they thought they had a plan to ward off and quickly contain any outbreaks. Instead, the move resulted in a surge of thousands of cases.
“It was a really horrible 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 an incorrect assumption, and the result is now 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 amount of the strain in 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, the report concluded.
Even before the Gaza case was detected, officials reviewing the initiative to tinker with the vaccine concluded that “the worst-case scenario has materialized,” the report said.
The report has not yet been published, and some changes will likely be made before the final version is released next month, the WHO said.
The strain that infected the baby in Gaza had lingered in the environment and mutated into a version capable of starting outbreaks. It was traced to polio viruses spreading last year in Egypt, according to genetic sequencing, the WHO said.
In 2022, vaccine-linked polio viruses were found to be spreading in Britain, Israel and the U.S., where an unvaccinated man was paralyzed in upstate New York.
Scientists now worry that the emergence of polio in a war zone with an under-immunized population could fuel further spread.
Racaniello said the failure to track polio carefully and to sufficiently protect children against the strain removed from the vaccine has had devastating consequences.
“Only about 1% of polio cases are symptomatic, so 99% of infections are silently spreading the disease,” he said.
The oral polio vaccine, which contains a weakened live virus, was withdrawn in the U.S. in 2000. Doctors continued to vaccinate children and eventually moved to an injected vaccine, which uses a dead virus and does not come with the risk that polio will be present in human waste. Such waste-borne virus could mutate into a form that triggers outbreaks in unvaccinated people.