The Africa Centres for Disease Control & Prevention says that while cases of mpox are steadily increasing across the continent, nearly three-quarters of them have no epidemiological link – meaning they’re being detected in people not being monitored by health workers, and who aren’t known to have been in contact with previously identified cases.
Africa CDC Director-General Dr Jean Kaseya said there are concerning gaps in the continental response in areas of surveillance, contact tracing, and data collection, and at least 68% of the cases can’t be tracked.
So far this year, there have been more than 32 400 suspected cases, of which about 6 440 have been confirmed, and around 840 mpox deaths reported across the continent. Most cases are in the Democratic Republic of Congo, reports Devex.
When new cases largely pop up in people under surveillance by health workers, it’s a good sign, said Dr Ngashi Ngongo, Africa CDC’s lead on co-ordination of the continent’s mpox response. But when it’s unclear how people contracted the virus, it’s a problem.
“That shows your surveillance is not working, which is the reality in most of these countries,” Ngongo added.
The goal is to monitor the contacts in at least 90% of cases. But Africa CDC said health workers have tracked the contacts of less than 4% of identified cases.
Tracking transmission
To effectively tackle this outbreak, responders must gain control over tracking how the disease moves through communities from person to person, but that’s not happening.
But the overall testing rate in Africa is 49.5% of suspected cases, compared with a goal of at least 80%.
There are a few reasons for this. African health workers don’t have access to a rapid test that would allow them to give patients their results quickly, Kaseya said. Most testing is done in laboratories, and it can take days to receive results.
This makes it challenging to conduct surveillance at local level because health workers don’t have the tools to rapidly identify cases within their communities. It also makes it difficult to contain the spread across national borders, because border officials can’t test people such as truck drivers, one of the sources of the mpox spread to new countries.
And of the suspected cases tested by laboratories, only 40.2% are positive – some of which could be false negatives.
Kaseya said the low positivity rate among those tested suggests problems in how the samples are collected, transported to laboratories, and analysis at the lab.
Most of those collecting samples haven’t been trained in what constitutes a quality specimen for testing for mpox. Logistically, as well, DRC has problematic terrain, with bad or non-existent roads making it difficult to transport the samples.
Thus, Kaseya said, the number of cases his agency reports is considered to be a significant underestimate.
This includes the number of countries experiencing outbreaks. So far Africa CDC has recorded cases in 15 countries, but this may be an under-representation. For example, Tanzania hasn’t officially declared a case, but several of its neighbouring countries have.
Without easy access to testing, health practitioners are often left to use “case definitions” – assessing a patient’s symptoms. But this can be imprecise, as it can miss cases, or count suspected cases that are actually other diseases with similar symptoms, like measles, chicken pox, and herpes.
Instead of cases popping up in individuals health workers have been tracking because they’ve been in contact with someone with mpox, health workers identify the vast majority of cases when people fall sick and seek care on their own.
For example, an mpox case of clade 1b, the new strain first recorded in DRC last year, was recently reported in India in a person who had just been to the United Arab Emirates. Kaseya said Indian authorities told his agency the person hadn’t been in contact with anyone from Africa.
“If this is the case, somehow we missed something,” Kaseya said.
‘Many unknowns’
While mpox has been present on the continent for decades, there are still a lot of unanswered questions about how this outbreak is unfolding, Kaseya said, like the dynamics driving transmission, and why so many children are contracting the virus. There’s also a need for more research into treatment options.
Three vaccines have received authorisation to be used against mpox in several countries, and there are several others in the development pipeline. But not all of them can be used for all populations.
Bavarian Nordic’s MVA-BN vaccine for mpox has been used in other jurisdictions, like the US, for several years. But it only recently received the WHO's prequalification, which allowed for its procurement by Gavi, the Vaccine Alliance and Unicef for broader use across Africa. Overall, some 2.5m doses of this vaccine have been secured for African countries.
However, it’s unclear how this vaccine affects children under 12, Ngongo said. When WHO prequalified the vaccine, it specified that it can be used “off-label” in children under 18 when “benefits of vaccination outweigh the potential risk”.
Kaseya blamed the international community for dropping the ball on researching mpox, which he said is part of the reason there are so many gaps in understanding.
In July 2022, WHO declared a public health emergency of international concern as mpox spread globally, and research focused on the clade 2b strain, which was circulating in Europe and the US, he said. But the clade circulating in Africa was sidelined.
“They knew there was a Clade 1 in Africa, but they didn’t conduct studies,” Kaseya said. Clade 1 is known for more serious infections and a higher mortality rate than clade 2b.
The international emergency was declared over in May 2023 after cases declined globally. But the disease continued to circulate in DRC, leading to the discovery of the clade 1b strain, last year – and ultimately the declaration of another public health emergency of international concern this August.
Now, health workers are attempting to mitigate the emergency but don’t have access to rapid tests, which might have not happened if research into developing them had been prioritised in recent years.
Kaseya said most of the unknowns around mpox are due to international partners “not wanting to see the reality” of what was occurring in Africa.
First test approved by WHO
Meanwhile, there’s diagnostic hope on the horizon as the WHO last week listed the first mpox in vitro diagnostic (IVD) under its Emergency Use Listing (EUL) procedure, an important step in improving global access to testing.
The approval of the Alinity m MPXV assay, manufactured by Abbott Molecular, will be pivotal in expanding diagnostic capacity in countries like Africa, where the need for quick and accurate testing has risen sharply, and where limited capacity and delays in diagnosis persist.
The presence of the virus is confirmed by nucleic acid amplification testing (NAAT), such as real-time or conventional polymerase chain reaction (PCR), as stated in the mpox virus (MPXV). And the recommended specimen type for diagnostic confirmation infection in suspected cases is lesion material.
The Alinity m MPXV assay is a real-time PCR test that enables detection of mpox (clade I/II) DNA from human skin lesion swabs. It is designed for use by trained clinical laboratory personnel who are proficient in PCR techniques and IVD procedures. By detecting DNA from pustular or vesicular rash samples, lab and health workers can confirm suspected mpox cases efficiently and effectively.
“This first mpox diagnostic test listed under the Emergency Use Listing procedure represents a significant milestone in expanding testing availability in affected countries,” said Dr Yukiko Nakatani, WHO Assistant Director-General for Access to Medicines and Health Products.
“Increasing access to quality-assured medical products is central to our efforts in assisting countries to contain the spread of the virus and protect their people, especially in underserved regions.”
The EUL process accelerates the availability of lifesaving medical products, like vaccines, tests and treatments, in the context of a Public Health Emergency of International Concern (PHEIC).
In August, the WHO had called on mpox IVDs manufacturers to submit an expression of interest for EUL, recognising the urgent need to bolster global testing capacities as the virus continued to spread.
So far, three additional submissions for EUL evaluation have been received, and discussions are ongoing with other manufacturers of mpox IVDs.
This will support countries which have not approved the medical products through their own approval processes to procure the critically needed tests through UN agencies and other procurement partners.
Devex article – The majority of mpox cases can't be tracked (Open access)
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