Polio has likely infected people in the Gaza Strip, representing a setback for global eradication efforts, a World Health Organization spokesperson said on Tuesday.
Gaza’s health ministry declared a polio epidemic across the Palestinian enclave on Monday after samples of the virus were found in sewage, although no human cases have been reported.
According to the WHO, polio is now endemic only in Pakistan and Afghanistan, but more than 30 countries, including Gaza’s neighbors Egypt and Israel, are still listed as subject to outbreaks. Any country risks a return of polio if outbreaks are not contained with mass vaccinations.
WHO spokesperson Christian Lindmeier told a U.N. press briefing that people had probably already been infected in Gaza, but detecting cases can be difficult since most cases of the potentially deadly viral disease are asymptomatic.
“Having vaccine-derived polio virus in the sewage very likely means that it’s out there somewhere in people,” Lindmeier said. “So the risk of it spreading further is there, and it would definitely be a setback for global efforts.”
He said an investigation and risk assessment were underway in Gaza. Poliomyelitis, spread mainly through the fecal-oral route, is a highly infectious virus that can invade the nervous system and cause paralysis and death in young children.
Cases of polio have declined by 99% worldwide since 1988 thanks to mass vaccination campaigns, and efforts continue to eradicate it completely.
The WHO has sent more than 1 million vaccines to prevent children from being infected in Gaza. Israel’s military, engaged in conflict with Hamas in Gaza after the group killed 1,200 people and kidnapped 253 in October 7 cross-border attacks, said last week it would start offering polio shots to its soldiers there.
James Elder, spokesperson for the U.N. children’s agency, said that more than nine months of conflict had led to a drop in polio vaccination rates from 99% to 89%. He voiced concerns about vaccines reaching people in need, given humanitarian access constraints into and within the enclave.
“The mass displacement, the decimation of health infrastructure, the horrendously insecure operating environment, they will make it much, much more difficult to do vaccinations, hence putting more and more children at risk,” Elder said.
Israel, which vets goods entering Gaza and is responsible for granting security clearance for aid convoys, blames U.N. inefficiency for aid delays. Gaza’s health ministry says over 39,000 people have been killed in Israel’s military offensive. Humanitarian workers believe the real death toll, including those killed by disease, is likely much higher due to high case numbers of Hepatitis A, dysentery, and other diseases among people displaced by the conflict .
