First Africa Polio Cases Linked to New Vaccine Detected, While Marburg and Cyclone Freddy Threaten Health
A child getting an oral polio vaccination.

Health authorities in Burundi have declared a national public health emergency response to an outbreak of circulating poliovirus type 2.

The World Health Organization’s (WHO) Africa region announced on Friday that polio had been detected in an unvaccinated four-year-old boy in Isale district in western Burundi and two other children who had been in contact with the child. 

Five samples from wastewater surveillance confirmed the presence of the circulating poliovirus type 2. 

Circulating vaccine-derived poliovirus are variant polioviruses that can emerge if the weakened live virus contained in oral polio vaccine, shed by vaccinated children, is allowed to circulate in under-immunized populations for long enough to genetically revert to a version that causes paralysis.

The Burundian government plans to implement a vaccination campaign to combat polio in the coming weeks, aiming at protecting all eligible children under the age of eight against the virus.

Meanwhile, the Global Polio Eradication Initiative (GPEI) announced on Thursday that a further six cases of circulating poliovirus type 2 had been detected in children in the DRC’s eastern Tanganyika and South Kivu provinces.

“The detection of the circulating poliovirus type 2 shows the effectiveness of the country’s disease surveillance. Polio is highly infectious and timely action is critical in protecting children through effective vaccination,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “We are supporting the national efforts to ramp up polio vaccination to ensure that no child is missed and faces no risk of polio’s debilitating impact.”

According to WHO, circulating poliovirus type 2 is the most prevalent form of polio in Africa and outbreaks of this type of poliovirus are the highest reported in the region, with more than 400 cases reported in 14 countries in 2022. 

These are the first instances of circulating poliovirus type 2 that are linked with novel oral polio vaccine type 2 (nOPV2) since roll-out of the vaccine began in March 2021. 

“While detection of these outbreaks is a tragedy for the families and communities affected, it is not unexpected with wider use of the vaccine,” according to GPEI.

“All available clinical and field evidence continues to demonstrate that nOPV2 is safe and effective and has a significantly lower risk of reverting to a form that cause paralysis in low immunity settings when compared to monovalent oral polio vaccine type 2 (mOPV2),” it added.

“To date, close to 600 million doses of nOPV2 have been administered across 28 countries globally, and the majority of countries have seen no further transmission of cVDPV2 after two immunization rounds.”

Equatorial Guinea’s Marburg testing conundrum

Dr Ahmed Ouma, acting director of the Africa CDC

Meanwhile, in mid-February, health authorities in Equatorial Guinea confirmed the country’s first ever case of Marburg virus disease in the western Kie Ntem province with concerns that cases may be undetected as the country has limited testing capacity. 

Over one month later, 12 cases — one confirmed case and 11 probable – and 12 deaths have been reported. The Africa CDC on Thursday attributed the inability to confirm the suspected cases to limited testing capacity in Equatorial Guinea.

According to the US Centers for Disease Control and Prevention (CDC), the polymerase chain reaction (PCR) test is one of the methods for diagnosing Marburg virus disease

While noting that Equatorial Guinea and several other African countries acquired and expanded their PCR testing network during the COVID-19 pandemic, Dr Ahmed Ouma, acting director of the Africa CDC, told Health Policy Watch that availability of the infrastructure for testing is just one of the several elements required for testing for the disease. 

In addition, he said there is also the need for manpower (laboratory scientists) and reagents. These three, he said, need to be at the same place for an effective diagnosis strategy.

“In the beginning, there was no capacity within Equatorial Guinea. That capacity has now been made available. Training is ongoing, and we expect that the situation of not being able to get laboratory diagnosis out quickly is going to change,” Ouma said.

Noting the variation in testing capacity on the continent, Ouma added that access to the affected population was a challenge in some areas, as the required equipment may not be easily deployable in rural areas affected by Marburg.

“We have a situation here where it was a very rural community that was affected and we are working around the clock with the government of Equatorial Guinea to ensure that laboratory capacity is on the ground,” he added.

Despite the challenges of diagnosis, Ouma revealed available knowledge regarding clinical diagnosis and management are being deployed in responding to the outbreak. This includes quarantining and managing cases that present like human hemorrhagic fever — monitoring individuals with such symptoms “so that they are not a danger to themselves and the rest of the community”.

Cyclone Freddy linked waterborne disease outbreaks

On 12 March, Malawi experienced landfall of Cyclone Freddy that has caused flooding, displacement of people and massive destruction of sanitation facilities now impeding current response efforts. Other countries affected by the cyclone are Madagascar and Mozambique. 

“The second passage of Cyclone Freddy has displaced 87,603 people and caused 238 deaths in Madagascar, Malawi and Mozambique. This is a 111% increase in the number of new displaced persons and a 1,685% increase in the number of new deaths. Cumulatively 70,014 displaced persons and 132 deaths have been reported from three AU Member States,” Ouma said.

Regarding the health impacts of the cyclone, Ouma said Africa CDC is working with several agencies including the World Food Programme (WFP), particularly focusing on mitigation initiatives to ensure that those who have been displaced are in an environment that has decent and acceptable sanitary facilities.

“We are ensuring that we avoid any outbreak of waterborne diseases and we are also working with the government to provide health facilities where they can be able to access health whenever they need it. Other arms of governments in the affected countries and other partners are actually also working very hard to provide water, food and transportation to safer ground and mitigate the possibilities of unhealthy and unsanitary living conditions. This is how we reduce or completely stop the outbreak,” Ouma said.

Image Credits: Sanofi Pastuer/Flickr.

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