A senior WHO official stated on Tuesday that circulating vaccine-derived poliovirus has been detected in Gaza sewage samples analyzed by researchers.
"We have not yet collected human samples," said Ayadil Saparbekov, the WHO's head of health emergencies in the occupied Palestinian territories, "so it remains unclear if anyone has actually been infected with the virus."
However, Saparbekov expressed his concern to reporters in Geneva via video link, saying, "I am very much worried."
He added that if an outbreak occurs in the strip, it could potentially spread internationally at a significant rate.
Palestinian health officials have also cautioned that thousands of Gazans are at risk of contracting the virus.
Saparbekov emphasized his deep concern about the spread of diseases in Gaza.
"I'm extremely worried about outbreaks happening in Gaza," he stated, referring to the confirmation late last year that hepatitis A was spreading, "and now we may have polio."
"With the crippled health system, lack of water and sanitation, as well as lack of access of the population to health services... this is going to be a very bad situation," he warned.
"We may have more people dying of different communicable diseases than from the injury-related diseases."
UN agencies have frequently warned of outbreaks of cholera and other communicable diseases in the blockaded Palestinian territory.
Since October, the Israeli regime has killed over 39,000 Palestinians, most of them women, children, and adolescents, in Gaza. It has been enforcing a near-total siege on the coastal territory, severely limiting the flow of food, medicine, electricity, and water into Gaza.