Africa steps up polio fight with advanced sequencing

AFRICA – The World Health Organization’s Regional Office for Africa (WHO AFRO), in collaboration with the U.S. Centers for Disease Control and Prevention (CDC) and the Gates Foundation, has launched an initiative to equip and train laboratories across Africa in advanced Sanger sequencing technology.

This technology, vital for mapping the poliovirus genome, plays a crucial role in expanding the fight against poliovirus by enhancing diagnostic capabilities and supporting early intervention.

As many African nations intensify vaccination efforts to protect children against poliovirus, early detection remains central to these strategies.

Although Africa was declared free of indigenous wild poliovirus in August 2020, an alarming rise in type 2 variant poliovirus (cVDPV2) cases poses an urgent threat.

In 2024 alone, 290 poliovirus cases have been detected in 23 African countries, highlighting the need for timely and accurate identification.

This year, WHO AFRO rolled out targeted training in advanced Sanger sequencing to diversify diagnostic techniques for polioviruses, aiming to reduce the time required for detection.

 These training sessions are designed to equip laboratory personnel with essential skills to operate this advanced technology and deliver timely results for public health decision-makers.

The precise nature of sequencing technology allows labs to identify genetic changes in poliovirus strains, providing data to monitor transmission patterns and viral mutations.

Through real-time mutation tracking, laboratories can detect emerging threats and respond with agility.

The poliovirus genome, comprising 7.5 kilobases, produces four key proteins (VP1 to VP4) that play different roles in the virus’s structure and infection mechanisms.

Of particular importance is the VP1 protein, which facilitates viral attachment to cells and is instrumental in tracking poliovirus spread. Until now, the focus of sequencing has largely been limited to the VP1 region.

However, the recent training has broadened the scope, allowing laboratories to analyze additional genome regions, including the five-prime untranslated region and parts of VP4 and VP2, thus enhancing classification accuracy.

The first training session, hosted in South Africa, offered laboratory personnel hands-on experience with advanced Sanger sequencing techniques.

Conducted under the Global Polio Eradication Initiative (GPEI), this training is part of a broader effort to ensure African countries are prepared to detect polioviruses quickly and accurately.

Ugandan participant Irene Turyahabwe highlighted how the expanded sequencing window now enables labs to classify poliovirus cases more precisely, bringing the region closer to eradicating polio.

 Dr. Jude Kfutwah, coordinator of the WHO Regional Polio Laboratory Network, emphasized that advanced sequencing will not only streamline the diagnostic process but also provide crucial evidence on the success of vaccination campaigns, which are essential for polio eradication.

 “The data gathered through this technology informs decision-making, ensuring timely deployment of public health interventions to prevent further spread of the virus,” Dr. Kfutwah added.

 WHO plans to expand this training to additional African nations, including Algeria, the Central African Republic, and Madagascar, where laboratories will benefit from the transfer of this vital knowledge.

 This regional expansion is a key step toward strengthening Africa’s collective capability in the polio eradication campaign.

Further supporting eradication efforts, WHO is strengthening 16 local polio laboratories to enhance environmental surveillance, including testing for poliovirus in stool and wastewater samples to track geographic transmission patterns.

By enabling faster processing and promoting inter-laboratory collaboration, these efforts strengthen Africa’s surveillance network, creating a unified front to eradicate poliovirus across the continent.

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