The World Health Organization and its partners are gearing up for an ambitious mass vaccination campaign in the Gaza Strip after an 11-month-old boy contracted the Palestinian enclave’s first case of polio in 25 years.

“All his limbs are now paralyzed,” the boy’s mother, Nevin Abu al-Jidyan, said in a telephone interview this week from her tent in Deir al-Balah in central Gaza. “The left side is more rigid. He is even unable to bend over. I cannot even help him sit.”