Before mpox made global headlines in 2022, it had already been quietly circulating among humans in Nigeria for nearly a decade. A new genomic study reveals how the virus spread—and how global neglect made it worse.
Key Points at a Glance
- Mpox circulated via human-to-human transmission in Nigeria since 2014
- Major outbreak could have been prevented with better surveillance and vaccines
- New genomic dataset is largest ever compiled for mpox
- Study highlights urgent need for global investment in regional epidemic response
The virus was spreading. Not silently, but ignored. Long before mpox became a global concern in 2022, it had already been circulating among humans in southern Nigeria. Now, a new study published in Nature confirms it: human-to-human transmission of mpox began as far back as 2014.
Using powerful genomic tracing, researchers from Scripps Research, Redeemer’s University in Nigeria, and a Pan-African network of public health partners analyzed mpox samples from Nigeria and Cameroon. The result is the most comprehensive genomic dataset ever assembled for the virus—and a sobering lesson in global health equity.
In total, the team examined 118 viral genomes from mpox cases recorded between 2018 and 2023. The findings reveal that 105 of the 109 Nigerian cases were caused not by animal spillover, but by sustained human-to-human transmission—shattering the long-standing assumption that mpox remains mostly zoonotic in nature.
“We could have very easily prevented the 2022 multi-country outbreak if countries in Africa were given better access to therapeutics, vaccines, and surveillance technologies,” says Edyth Parker, one of the study’s lead authors. “We cannot neglect epidemics until they get exported to the Global North.”
The virus responsible for the 2022 global spread had accumulated a surprising number of mutations. This prompted suspicions that it had been circulating quietly for years. But without sufficient genomic data from Africa, there was no way to confirm the timeline—until now.
The breakthrough came thanks to a coordinated scientific effort across West and Central Africa, where researchers generated and shared viral genomes through a continent-wide consortium. By pooling data and methods, the team produced a dataset three times larger than any previously available.
Their phylogenetic analysis traced the virus’s origins to southern Nigeria in August 2014. From there, it spread to 11 states, largely undetected until 2017. The study also confirmed ongoing zoonotic spillovers in both Nigeria and Cameroon, though the latter had no evidence of sustained human transmission.
“Mpox is no longer just a zoonotic virus in Nigeria,” Parker says. “This is very much a human virus now.”
Two key samples from southern Nigeria were genetically similar to Cameroonian strains, suggesting viral movement across national borders—something scientists believe is more common than current data reveals. This points to a major blind spot in global health: the lack of wildlife surveillance in areas where humans and animals closely interact.
“There’s likely a lot more bi-directional viral movement happening between these countries,” says Parker. “But we just don’t have the wildlife sampling to detect it.”
The implications are clear. The world missed an opportunity to contain mpox before it went global. And unless access to diagnostics, vaccines, and real-time genomic tools improves in under-resourced regions, history is bound to repeat itself.
As Christian Happi, senior author of the study and director of the Institute of Genomics and Global Health in Nigeria, has long argued: surveillance must begin where the outbreaks do—not where they end.
The study is both a scientific triumph and a call to action. In the wake of COVID-19 and amid growing fears of future pandemics, the lesson is simple but urgent: global health depends on global inclusion.
Source: Scripps Research
