BRAZZAVILLE: Five African countries have successfully interrupted transmission associated with poliovirus type 2 outbreaks, marking an important advance in the global fight to eradicate a disease capable of causing irreversible paralysis.
The World Health Organization (WHO) Regional Office for Africa confirmed the closure of outbreaks in Burundi, Ghana, Guinea-Bissau, the Republic of the Congo and Uganda following independent technical assessments conducted between January and June 2026.
The assessments examined epidemiological evidence, laboratory findings, population immunity, vaccination campaign quality and disease-surveillance performance before concluding that transmission associated with the respective outbreaks had been interrupted.
The announcement represents a major public-health achievement for the five countries, but health authorities are stressing an equally important message: closing an outbreak does not mean the threat of polio has disappeared permanently.
Countries must continue vaccinating children, identifying suspected cases rapidly and maintaining sensitive surveillance systems because poliovirus can be imported again from areas where transmission continues.
Independent teams confirm transmission interrupted
Separate assessments were carried out by teams from the Independent Outbreak Response Assessment (OBRA) mechanism.
After reviewing surveillance, laboratory and epidemiological data, the teams determined that the outbreaks could be technically closed.
WHO subsequently confirmed the closure of the poliovirus type 2 outbreaks in all five countries.
Dr Mohamed Janabi, WHO Regional Director for Africa, said the achievement demonstrated the impact of coordinated national and community action.
“These outbreak closures demonstrate what can be achieved through strong national leadership, dedicated health workers and close collaboration between governments, communities and partners. While this is an important milestone, it is not the end of the journey. Continued vigilance, strong surveillance and high immunization coverage remain essential to protect children and prevent future outbreaks.”
His warning reflects one of the central challenges facing global polio eradication: a country can successfully interrupt a particular chain of transmission while remaining vulnerable to future introduction of the virus.
Recent poliovirus detection in Madagascar following the previous closure of an outbreak has reinforced that concern.
What does ‘polio outbreak closure’ actually mean?
An outbreak closure is a technical, country-specific determination that available evidence demonstrates transmission associated with a particular outbreak has been interrupted.
It does not mean poliovirus can never be detected again in that country.
WHO says the process involves an independent OBRA assessment followed by technical review and a decision by the WHO Regional Office for Africa.
That distinction is particularly important when communicating polio milestones to the public.
The African Region was certified free of wild poliovirus in 2020, but outbreaks caused by other polioviruses, including circulating vaccine-derived poliovirus, can still occur when immunity gaps allow the virus to circulate in under-immunised communities.
The latest closures therefore represent another step towards eradication rather than the end of polio-related risk across the continent.
Burundi strengthened vaccination after 2023 outbreak
Burundi declared a circulating poliovirus type 2 outbreak in March 2023.
Health authorities responded by intensifying routine immunisation and surveillance activities with support from the Global Polio Eradication Initiative (GPEI).
The response included targeted vaccination campaigns, enhanced epidemiological investigations and expanded environmental surveillance designed to detect poliovirus circulation even before paralytic cases were identified.
These interventions helped authorities close immunity gaps and ultimately interrupt transmission.
The experience highlights the importance of acting quickly after detection. Because many poliovirus infections cause no obvious symptoms, waiting until multiple cases of paralysis appear can allow transmission to continue unnoticed.
Republic of the Congo maintains surveillance after final detection
In the Republic of the Congo, authorities strengthened surveillance and conducted multiple vaccination campaigns after poliovirus detections.
The country's last detection linked to the outbreak was reported in December 2023.
Subsequent efforts focused not only on maintaining vaccination but also on keeping surveillance sensitive enough to identify any renewed transmission, particularly in populations considered at higher risk.
That prolonged period of monitoring formed part of the evidence reviewed before the outbreak was declared closed.
Uganda responds after 2024 poliovirus detection
Uganda intensified surveillance and outbreak-response activities following a poliovirus detection in May 2024.
Authorities maintained coordination at both national and subnational levels while strengthening systems designed to identify suspected cases and monitor transmission.
Uganda also invested in laboratory capacity, improving its ability to detect poliovirus and other vaccine-preventable diseases more rapidly.
Faster laboratory confirmation can significantly shorten the interval between virus detection and a targeted vaccination response — an important advantage when attempting to interrupt transmission.
Ghana expands laboratory capacity
Ghana's outbreak response similarly combined disease surveillance with rapid public-health action.
Investment in laboratory systems complemented vaccination and surveillance work, increasing the country's capacity to recognise poliovirus circulation and respond quickly.
Both Ghana and Uganda upgraded laboratory capacity in 2026, according to WHO, strengthening diagnostic readiness not only for polio but for other vaccine-preventable diseases.
Such investments can have benefits beyond a single outbreak by leaving countries with stronger surveillance infrastructure for future infectious-disease threats.
Guinea-Bissau records no detection since 2021
Guinea-Bissau's experience demonstrates how long sustained surveillance can continue before an outbreak is formally closed.
The country has reported no poliovirus detections since July 2021.
Authorities and health partners focused particularly on reaching underserved populations through targeted immunisation campaigns while strengthening surveillance.
Reaching children who are routinely missed by health services is critical because pockets of low vaccination coverage can create conditions in which poliovirus continues circulating even when overall national coverage appears relatively strong.
Mike McGovern, Chair of the GPEI Polio Oversight Board and Rotary International's International PolioPlus Committee, described each outbreak closure as another step towards protecting children from paralysis.
“Every outbreak closed means more children protected from a disease that can cause lifelong paralysis. Rotary is proud to stand alongside governments and health workers across Africa as we continue the effort to end polio once and for all.”
Why surveillance matters even after the final case
Polio surveillance is more complex than simply counting diagnosed infections.
Health systems monitor cases of acute flaccid paralysis (AFP) — sudden weakness or paralysis, particularly in children — because such cases can potentially signal poliovirus infection.
Environmental surveillance can also test sewage or wastewater for traces of poliovirus, allowing health authorities to identify circulation even when no paralytic case has yet appeared.
Across the African Region, countries have strengthened both AFP and environmental surveillance.
Laboratory modernisation undertaken in 2025 also aimed to reduce the time required to detect poliovirus, enabling authorities to launch outbreak responses sooner.
WHO says geospatial technology has increasingly become part of this work.
The expanded use of Geographic Information Systems (GIS) has helped vaccination programmes locate previously missed settlements, map population movement and improve vaccination microplanning, particularly in remote and border communities.
The technology can help health teams answer one of the most difficult questions in eradication programmes: Which children are still being missed?
Reaching every child remains the central challenge
Polio has no cure, but it is preventable through vaccination.
That makes population immunity fundamental to eradication.
When sufficiently high numbers of children are vaccinated, opportunities for the virus to circulate become increasingly limited.
Problems emerge when some communities remain repeatedly underserved because of geographic isolation, population movement, insecurity, health-system weaknesses, vaccine hesitancy or barriers to routine immunisation.
UNICEF Regional Directors Etleva Kadilli, for Eastern and Southern Africa, and Gilles Fagninou, for West and Central Africa, credited governments, communities and frontline workers for the latest milestone while warning against allowing progress to reduce urgency.
“These milestones belong first and foremost to the governments, communities and frontline health workers who have worked tirelessly to protect children from polio. Their dedication shows that progress is possible, even in the most challenging settings. While outbreak closures are an important milestone, they are not the end of the work. We must keep our focus on strengthening routine immunization and reaching every child with lifesaving interventions, so that this progress is sustained.”
Community trust has become an increasingly important component of vaccination programmes.
Health workers must often reach households repeatedly, explain why multiple vaccination rounds may be necessary and counter misinformation that can undermine vaccine acceptance.
In border areas and among mobile populations, coordination between neighbouring countries becomes equally important because poliovirus does not respect administrative boundaries.
Polio investments strengthening wider health systems
The infrastructure developed to eradicate polio can also strengthen responses to other infectious diseases.
Laboratory networks, disease-surveillance officers, geographic mapping, community mobilisation and rapid-response mechanisms created for polio can be used during other public-health emergencies.
Thabani Maphosa, Gavi's Chief Country Delivery Officer, said the latest achievement therefore carried implications beyond polio alone.
“This is a positive development not only for the fight against polio but also for the overall effort to save lives through stronger health and immunization systems. The investments countries have made in reaching missed children, community engagement, strengthened surveillance, mapping, and outbreak response will have impact far beyond these polio outbreaks. They strengthen our ability to ensure that every child remains safe from polio and other vaccine-preventable diseases, and to protect communities against infectious disease outbreaks.”
International partners support eradication effort
The five countries' responses have been supported through the wider Global Polio Eradication Initiative, a public-private partnership led by national governments alongside WHO, Rotary International, the US Centers for Disease Control and Prevention, UNICEF, the Gates Foundation and Gavi, the Vaccine Alliance.
Countries and health partners also acknowledged support from Canada, the European Investment Bank, Germany, the United Arab Emirates and other donors to GPEI.
Yet financing and technical assistance alone cannot eradicate polio.
The final stages depend heavily on national health workers locating missed children, laboratories detecting viruses quickly, public-health teams investigating cases immediately and communities continuing to accept vaccination.
An important victory — but not permission to relax
The closure of five outbreaks demonstrates that poliovirus transmission can be interrupted even across countries facing very different geographical, logistical and health-system challenges.
The common elements were strikingly similar: rapid detection, political commitment, vaccination, sensitive surveillance, laboratory capacity and community engagement.
But those same systems must remain in place after an outbreak closes.
Poliovirus can return through importation, and gaps in routine immunisation can again leave children vulnerable.
For families, the message remains straightforward: children should receive all recommended routine vaccinations, suspected sudden weakness or paralysis should be reported promptly to health services, and communities should rely on trusted public-health information.
For governments, the challenge is more demanding.
The success announced in Burundi, Ghana, Guinea-Bissau, the Republic of the Congo and Uganda must now be converted into sustained population immunity rather than treated as an endpoint.
Every interrupted outbreak removes another chain of transmission.
But the global goal remains larger: a world in which no child anywhere faces paralysis from poliovirus.
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