What to know about polio vaccination campaign in Gaza after 1st first case in 25 years

A mass polio vaccination campaign is underway in Gaza to inoculate children after the first case in 25 years was recently detected in the strip.

Several organizations -- including the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), the Hamas-run Gaza Ministry of Health and other partners -- began the campaign on Sunday in central Gaza, where the case was confirmed.

The WHO has sent more than 1 million vaccine doses with the goal of vaccinating more than 640,000 children under age 10. The campaign will be rolled out in three-day phases each in central, southern and northern Gaza, according to Dr. Richard Peeperkorn, WHO representative for the Palestinian territory,

The UN estimates that in 2022, polio vaccination coverage, conducted through routine immunization, was at 99%.

However, since the outbreak of the war, this percentage has fallen. According to the latest WHO-UNICEF routine immunization (WUENIC) report, the number is estimated to be at 89% in 2023 due to the number of newborns not vaccinated.

Israel has agreed to limited pauses in the fighting, for about six hours a day, to facilitate the campaign, according to the WHO.

Children will receive two drops of novel oral polio vaccine type 2 (nOPV2), which has been used for outbreak response under the WHO’s Emergency Use Listing approval since March 2021.

“We are targeting 157,000 children under 10 [in central Gaza]. We will do it for three consecutive days and, if needed, we’ll add a day,” Peeperkorn said on Sunday.

The vaccination will target 138 different sites including hospitals, medical points, schools and community points -- including water and food distribution points -- according to the WHO.

Among those participating in the vaccination campaign is the medical nonprofit MedGlobal. Five of the organization's medical treatment points in Gaza are ready to administer vaccines.

Dr. John Kahler, a pediatrician and co-founder of MedGlobal, who has been on multiple medical missions to Gaza, said temporary pauses are not enough to fix long-term systemic issues, but this proves they can happen for critical medical situations.

"First of all, it shows how collapsed the public health system is," he told ABC News. "But it also shows that it is possible for both sides to come to some type of a temporary -- but important -- agreement to permit [vaccinations] to happen."

UNICEF said during the first two full days of the vaccination campaign, about 160,000 children received a dose of polio vaccine.

Poliovirus was first detected in sewage samples from Deir al-Balah and Khan Younis -- in central and southern Gaza, respectively -- in mid-July, in tests conducted by the Ministry of Health in coordination with the United Nations.

"The presence of the virus that causes polio ... represents a new health disaster," the ministry said in a statement at the time. "There is severe overcrowding, a scarcity of available water and its contamination with sewage water, the accumulation of tons of garbage and the occupation's prevention of the entry of hygiene materials, which creates a suitable environment for the spread of various epidemics."

In mid-August, the Ministry of Health reported the first case of polio in 25 years in a 10-month-old child who had not been vaccinated. Doctors suspected polio after symptoms resembled the virus, which was confirmed in test conducted in Amman, the capital of Jordan.

Kahler said the true number of polio cases is likely much higher with many that have got undetected.

"If you really do have one case of paralytic polio, you have, by definition, hundreds or more," he said. "Remember, 90% of polio is asymptomatic. So, this is why it spreads. It's highly contagious...Given the breakdown in the infrastructure, there will be no way of knowing how many."

Polio largely affects children under age 5 and can lead to paralysis or death. According to the Palestinian Central Bureau of Statistics, there are about 341,000 children under the age of five in Gaza.