Sudan will resume immunising children against polio after detecting circulating vaccine-derived poliovirus type 2 (cVDPV2) in its waster water, as six other African countries have reported either cases or positive environmental samples over the past two weeks.

Mali and Nigeria reported one case each, Yemen reported three cases and Angola, Côte d’Ivoire and Sierra Leone reported positive environmental samples.

Sudan’s Federal Ministry of Health (FMOH) announced that it will launch a polio vaccination campaign next month after cVDPV2 was detected in six wastewater samples between last September and January.

The states of Red Sea, Kassala, Gedaref, River Nile, Northern, White Nile, Blue Nile and Sennar are being targeted.

War, heatwave undermine health services

War between two opposing military forces in Sudan has halted the country’s immunisation drive for an entire year. To make matters worse, the country is in the grips of a debilitating heatwave with temperatures exceeding 40ºC. Schools were closed from Monday and are expected to remain closed for at least two weeks.

Looting and attacks on health facilities have also affected services, with over a million polio vaccines destroyed as a result.

The breakdown in health services, including routine vaccination, significantly increases the risk of spread of communicable diseases amid outbreaks of cholera, dengue, malaria and measles reported from numerous states.

Sudan reported the emergence of variant poliovirus type 2 in January 2024. It was detected in six wastewater samples collected from September 2023 to January 2024 in the Port Sudan locality, Red Sea State.

The FMOH, with support from the World Health Organization (WHO), has completed field investigations and a risk assessment to determine the extent of the virus circulation. 

This new detection comes 14 months after Sudan declared an outbreak of variant poliovirus type 2, from an unrelated emergence of the virus, which was detected in a 4-year-old child in West Darfur in October 2022. 

In response to that outbreak, the FMOH, in collaboration with the United Nations Children’s Fund (UNICEF) and WHO, delivered and distributed 10.3 million doses of oral polio vaccine in a nationwide polio vaccination campaign in March 2023, reaching around 8.7 million children aged under 5 years (98% of all children of this age group in Sudan).

Wastewater detection

“While no vaccination campaign has taken place since April 2023 due to the ongoing conflict, surveillance for poliovirus in children – conducted by searching intensely for acute flaccid paralysis (AFP), the most common indicator of polio infection – and in wastewater has been strengthened to swiftly detect any presence of the virus,” according to the WHO.

While the FMOH has not found any children paralysed due to the new emergence, the detection of poliovirus in wastewater samples means that children across the country are at high risk. 

“The new detection has only redoubled our commitment to safeguarding our children’s future. In collaboration with partners, we are mobilising an outbreak response campaign to ensure that every child under five years in accessible areas receives the polio vaccine, and special plans will follow for hard-to-reach areas,” said Dr Dalya Eltayeb, Director-General of Primary Health Care in Sudan’s FMOH.

There is no cure for polio, a highly infectious viral disease that mainly affects children aged under five years, but it can be prevented through vaccination. Caregivers must ensure that during upcoming vaccination campaigns, all children aged under 5 years receive oral polio vaccine drops every time they are offered. They should also receive routine vaccinations according to their age.

“The ongoing war is undoing the enormous gains the country has registered on childhood vaccinations,” said Dr Tedla Damte, Chief of Health and Nutrition at UNICEF Sudan.

“Millions of displaced children on the move cannot be protected against life-threatening diseases, like polio, yet these can be prevented through vaccination. Health systems are overstretched, subsequently impacting the delivery of health services including vaccinations. UNICEF remains committed to supporting vaccination campaigns to protect children, no matter what,” he emphasised.  

Image Credits: WHO Sudan.