New mpox virus transmission routes are emerging with children now a high-risk group; Inadequate testing capacity is stymying efforts to contain the outbreak.

The outbreak of mpox virus (MPXV) clade I (akin to a variant) in the Democratic Republic of Congo’s (DRC) South Kivu province shows no sign of abating. An observational study (currently under review) (https://apo-opa.co/43d2Jvc) has now revealed that MPXV clade I can spread through both heterosexual contact and close community level contact, with children now constituting by far the biggest group of MPXV cases and death. Lack of comprehensive testing capacity is impacting outbreak understanding, response and containment.

The 2022 MPVX clade II global outbreak caused concern because of a wider geographical spread and a rise in fatalities, however this MPXV clade I outbreak marks an important change as transmission routes now appear to be expanding. There is an urgent need (https://apo-opa.co/48OfEox) for more in-depth investigation to better understand mpox transmission dynamics to guide controls and response plans, as well as enhanced surveillance, and equitable access to vaccines, diagnostics and treatments for all affected populations. Without access to testing, it is also unclear how comorbidities, particularly immunocompromised conditions like HIV, may influence the severity and transmission dynamics of the virus.

“The mpox situation in the DRC is deeply alarming and the lack of tests for both mpox and HIV means it’s unclear just how bad the mpox situation is and what the underlying comorbidities are,” said Dr Ayoade Alakija, who is Chair of the Board at FIND. “Like the COVID-19 pandemic, the people that are being prioritized for tests, treatment and vaccination are not in the outbreak countries in Africa. We can either mobilize resources and fight the deadly mpox outbreak now in the DRC, or we can let the virus continue to spread and fight it when it is imported into other countries.”

DRC reported the first ever mpox cases in humans in 1970, and historically the country has only reported MPXV clade I. Clade I is the deadliest form of the virus, and this first recorded heterosexual transmission and close community contact transmission mark a pivotal shift in its evolution. The DRC faces significant challenges in disease verification, with only a fraction – 16% – of suspected cases undergoing PCR testing due to limited diagnostic resources. This testing shortfall has yielded a 60% positivity rate, signalling a potential underestimation of the outbreak. From the start of 2022 to January 2024, the country reported a staggering 21,630 suspected MPXV cases and 1,003 deaths, with the brunt borne by children: around 85% of deaths (https://apo-opa.co/3Vek7hl) in this period were recorded as children under 15 years of age.

Closing the gap between suspected and confirmed cases is crucial to tailoring a precise response and stopping the spread of MPXV. Enhanced surveillance measures and increased access to testing are imperative to gain a clear understanding of the outbreak and to deploy targeted interventions effectively.

“Testing capacity for mpox and HIV in the DRC is severely limited, meaning that many likely cases of mpox in the country are being treated as suspected cases only,” Dr Sergio Carmona, acting CEO and Chief Medical Officer at FIND. “Given the persistent inequities in testing capacity, FIND is urgently working with partners to fast-track both the rollout of tests and develop new diagnostic tools that can be used at the point of care to deliver results faster.”