A child in Gaza has a strain of polio

LONDON (AP) — The child in Gaza who was recently paralyzed by polio was infected with a mutated strain of the virus that vaccinated people throw away in their waste, according to scientists who say the case is the result of “an unqualified failure ” of the 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 leg of the unvaccinated 10-month-old. The little 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 baby’s illness showed the failure of a global effort by the World Health Organization and its partners to fix serious problems in their otherwise highly successful eradication campaign that nearly destroyed the highly infectious disease. Separately, a draft expert report 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 paralysis in millions of children worldwide. But that virus was removed from the vaccine in 2016 in hopes of preventing vaccine-derived outbreaks.

Public health officials knew this decision would leave people unprotected against that strain, but they believed they had a plan to quickly avoid and contain any outbreaks. Instead, the move led to an increase in thousands of cases.

“It was a really horrible strategy,” said virologist Vincent Racaniello of Columbia University, who was not involved in the report or WHO. “The decision to change vaccines was based on an incorrect assumption, and the result is that we now have more polio and more paralyzed children.”

A draft 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 control outbreaks.

The plan led to vaccine-related 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 modify the vaccine concluded that “the worst-case scenario had materialized,” 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 persisted in the environment and mutated into a version capable of triggering outbreaks. It was traced to the polio viruses that spread last year in Egypt, according to genetic sequencing, the WHO said.

In 2022, vaccine-related polio viruses were found to be spreading in the UK, Israel and the US, where an unvaccinated man was paralyzed in upstate New York.

Scientists now fear that the emergence of polio in a war zone with an under-immunized population could further fuel the spread.

Racaniello said the failure to closely monitor polio and sufficiently protect children against the strain removed from the vaccine had devastating consequences.

“Only about 1 percent of polio cases are symptomatic, so 99 percent of infections are silently spreading the disease,” he said.

The oral polio vaccine, which contains a live, weakened virus, was withdrawn in the US in 2000. Doctors continued to vaccinate children and eventually switched to an injected vaccine, which uses a dead virus and carries no risk of poliomyelitis to be present. in human waste. Such a virus transmitted through waste could mutate into a form that triggers outbreaks in unvaccinated people.

The report’s authors criticized leaders at the WHO and its partners, saying they were unable or unwilling “to recognize the seriousness of the evolving problem and take corrective action.”

WHO spokesman Oliver Rosenbauer admitted that the vaccination strategy had “exacerbated” the risk of vaccine-related epidemics.

He said in an email that immunization “has not been implemented in a way that quickly stops outbreaks or prevents the emergence of new strains.” Rosenbauer said missing vaccination targets is the biggest risk to allowing vaccine-related viruses to emerge.

“You have to reach children with the vaccines … regardless of the vaccines used,” he said.

WHO estimates that 95% of the population needs to be immunized against polio to stop outbreaks. The UN health agency said only about 90 percent of Gaza’s population had been vaccinated earlier this year.

To try to stop polio in Gaza and across the region, the WHO and its partners are planning two rounds of vaccination campaigns later this week and next month, with the goal 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.

The WHO said on Thursday it had reached an agreement with Israel for limited pauses in fighting in Gaza to allow vaccinations. The agency’s representative in the Palestinian territories said the first three-day break would begin Sunday in central Gaza. This will be followed by another three-day break in southern Gaza and then another break in northern Gaza. Breaks were to last eight or nine hours each day.

Racaniello said it was “unethical” for the WHO and its partners to use a vaccine that is not licensed in rich countries precisely because it may increase the risk of polio in unvaccinated children.

The oral polio vaccine, which has reduced infections globally by more than 99%, is easy to make and distribute. Children only need two drops per dose which can be administered by volunteers. The oral vaccine is better at stopping transmission than the injected version and is cheaper and easier to administer.

But as the number of polio cases caused by the wild virus has declined in recent years, health officials have struggled to contain the growing spread of vaccine-related cases, which now comprise the majority of polio infections in more than a dozen of countries, in addition to 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. “If we really want to eradicate polio, then we need to stop using the live (attenuated) virus vaccine.”