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For the first time ever, a circulating variant poliovirus type 3 (cVDPV3) was fully sequenced in Cameroon, marking a major milestone in Africa’s efforts to detect and respond faster to polio outbreaks.
Poliovirus has three types: 1, 2, and 3. Although wild polio type 3 was declared eradicated in 2019, variant type 3 can still appear where immunity is low, making quick detection and response essential to contain outbreaks.
Cameroon’s expanded sequencing capacity now allows its national polio lab to detect and provide provisional results before confirmatory testing by the regional reference lab in Ghana. Local provisional results help speed up outbreak response by reducing delays.
On this occasion, although a sample was still provided to Ghana for quality assurance, detection and intervention commenced promptly at the national level. This approach enabled a more rapid response, enhanced national ownership, and demonstrated the significant impact of Africa’s expanding network of sequencing laboratories on efforts to eradicate polio.
Cameroon’s milestone is one aspect of ongoing change in Africa, supported by WHO AFRO’s polio laboratory programme led by Dr. Kfutwah. “Expanding polio sequencing labs in the African region is a key goal that will significantly aid efforts against polioviruses and other vaccine-preventable diseases, representing progress in public health for the área.”- Dr Kfutwah
Two key flagship initiatives are spearheading this transformation. First, countries are expanding in-country sequencing laboratories to bring virus detection closer to where outbreaks occur. By bringing sequencing closer to where outbreaks occur, countries are cutting delays and boosting rapid response capacity. A clear example comes from Nigeria: the recent addition of the Ibadan sequencing laboratory has led to a 41% reduction in variant polio type 1 sequencing turnaround time for isolates from across the country.
Prior to the establishment of the Ibadan sequencing facility, samples were required to be transported over long distances, frequently crossing international borders. With the development of local capacity within Nigeria, results are now delivered more promptly and consistently, enabling teams to respond more efficiently and minimizing opportunities for viral transmisión and spread.
At the same time, the region is embracing next-generation technologies to make virus detection even faster and more flexible. One of these is the MinION nanopore platform, a small, easy-to-carry device that can read the genetic code of viruses quickly, even outside of big laboratories.
By bringing this kind of technology closer to where outbreaks may occur, health teams can detect and respond to the virus much faster, helping to protect more children and stop the spread of polio.
A recent analysis of two variant type 3 isolates utilized both MinION and Sanger sequencing methods. MinION, when used near outbreaks, typically delivers results more quickly than Sanger sequencing, which can be important for timely outbreak response.
Response time can determine whether an event remains contained locally or becomes a large-scale outbreak.
The recent detection in Cameroon marks increased national leadership and resilience in Africa’s polio response, as countries now generate their own data and act quickly instead of relying solely on foreign labs.
The expansion of laboratories and the use of advanced tools are improving the speed and effectiveness with which countries can detect and respond to poliovirus. In Africa, a large and interconnected region, these changes will demonstrate technical progress in disease detection and outbreak prevention.
With each day saved in detection, more children are protected and Africa moves closer to its goal: a continent free of polio.
Distributed by APO Group on behalf of World Health Organization (WHO) – Cameroon.