“At least two rounds of [orally delivered polio vaccine] will be necessary to shut down transmission,” the World Health Organization (WHO) and UN Children’s Fund (UNICEF) explained in an update.
The development comes after vaccine-derived poliovirus type 2 was identified on 16 July by the Global Polio Laboratory Network in sewage samples collected on 23 June from Khan Younis and Deir Al-Balah.
Paralysis cause search
Three cases of paralysis were reported in late July by the Gazan health authorities and samples were sent to Jordan for testing. Acute flaccid paralysis can have numerous causes, including poliovirus, according to WHO, which underscored that the results have yet to be published for the affected individuals from north Gaza, Deir Al-Balah and Khan Younis.
The UN health agency noted previously that although Gaza had excellent polio vaccine coverage before the war, months of fighting have created the “perfect environment” for the weakened polio virus vaccine to mutate into a stronger version capable of causing paralysis among those who are not fully immunized.
The WHO and UNICEF also expressed concern about any delays to the delivery of the polio vaccine and vital cold chain equipment amid ongoing heavy fighting and insecurity in the enclave and as regional tensions linked to the war in Gaza threaten further violence.
Plea for aid workers
Humanitarian pauses “need to be in place to vaccinate children to mitigate the risk of transmission”, the UN agencies insisted, after WHO Director-General Tedros Adhanom Ghebreyesus approved the release of 1.23 million doses of novel oral polio vaccine type 2 (nOPV2) for use in Gaza in a bid to vaccinate more than 640,500 children under 10 years of age.
For the mass vaccination campaign to work, “safe and sustained access and protection of health workers is required,” the UN agencies insisted while noting that only 16 out of 36 hospitals are “partially functional” in Gaza.
Only 48 out of 107 primary healthcare facilities remain operational.
“The impact on the health system, insecurity, inaccessibility, population displacement and shortages of medical supplies have contributed to reduced immunisation rates,” said the agency update. “Coupled with poor quality of water and destruction of sanitation, there is a heightened risk of vaccine-preventable diseases, including polio and other outbreaks.”
In Gaza, routine immunisation coverage for polio dropped from 99 per cent in 2022 to less than 90 per cent in the first quarter of 2024, according to WHO and UNICEF.