#17,990
While the spread of HPAI H5 into cattle currently has much of our attention, we continue to follow other other infectious disease threats, including Mpox (formerly Monkeypox).
While the global health emergency over the international spread of a new clade (IIb) of Mpox was declared over 11 months ago, we continue to see sporadic infections around the globe, and a more dangerous clade I mpox virus continues to rage ( > 12,000 cases in 2023) in the DRC.
Four months ago, the WHO Reported the 1st Confirmed Cluster Of Sexually Transmitted MPXV Clade 1 in the DRC, warning that `The risk of mpox further spreading to neighbouring countries and worldwide appears to be significant.'
Last month we looked at a report in Eurosurveillance: Ongoing Mpox Outbreak in South Kivu Province, DRC Associated With a Novel Clade I Sub-lineage, which contained the first genomic analysis of samples from a previously unaffected region of the DRC.
This study revealed a novel clade I sub-linage had emerged - most likely from a zoonotic introduction - with changes that may render current CDC tests unreliable.
And just a week ago, we looked at a press release from the European Society of Clinical Microbiology and Infectious Diseases on an upcoming presentation at next week's ECCMID 2024 meeting in Barcelona, Spain that found that Mpox-specific antibodies wane within one year after MVA-BN vaccination.
Outbreak of mpox caused by Monkeypox virus clade I in the Democratic Republic of the Congo
Epidemiological update
5 Apr 2024
Since the publication of the Threat Assessment Brief ‘Implications for the EU/EEA of the outbreak of mpox caused by Monkeypox virus clade I in the Democratic Republic of the Congo in December 2023’ [1], there has been a large increase in the number of mpox cases reported in the Democratic Republic of the Congo (DRC) [2,3]. Since 2023 and as of 29 March 2024, DRC reported a total of 18 922 suspected mpox cases including 1 007 deaths.In 2024, and as of 29 March, 4 488 cases have been reported, of which 319 have been confirmed. A total of 279 deaths have been reported in the country in 2024 (CFR: 6.7%). Mpox cases have been reported in 23 of 26 provinces of the DRC [4].
Background
According to the World Health Organization (WHO), and as of 23 November 2023, the majority of the cases were reported in the central and northern regions of the DRC: Equateur, Mai-Ndombe, Sankuru, and Tshopo [3].
According to the information available, the vast majority of infections in the ongoing outbreak continue to be caused by monkeypox virus (MPXV) clade I, although only about 10% of cases have been laboratory-confirmed [3].
All known routes of transmission of MPXV (zoonotic, human-to-human close contact, and human-to-human sexual transmission) are reported in the ongoing DRC outbreak, but their respective proportion in this outbreak are not defined. In 2023, sexual transmission of MPXV clade I was first documented in a cluster of six mpox cases (five male and one female) from Kenge, Kwango province in DRC, as reported in ECDC’s most recent threat assessment [3,5].
In the current epidemiological reports, children younger than 15 years old account for 70% of the total cases. This age group also accounts for 88% of total deaths in the country [4]. Historically, mpox has been documented with high counts and mortality rates among children in the DRC [6]. The high incidence of cases among children is most likely linked to the non-sexual human-to-human transmission route. This route could include household contacts of adults who have contracted the disease through both human-to-human transmission (sexual or non-sexual) or zoonotic transmission via spill-over events from small animals.
Some cases have also been reported among sex workers in the mining area of Bukavu (Kamituga) in South Kivu [3]. Of 51 mpox cases hospitalised between September 2023 and January 2024, 24 were sex workers, five of whom were male [3,7]. Considering that sex work is likely concentrated around mining areas and that there are no direct travel connections to Europe, the relevance of this transmission route for potential importation into sexual networks in the EU is likely limited, including into sexual networks of men-who have sex with men (MSM), where the majority of mpox transmission in the EU has occurred to date. However, local spread into neighbouring Rwanda and Burundi is possible, and it is important to monitor the situation there as travel from Kigali to Europe is more common.
Based on the MPXV genomic sequences published on GISAID EpiPox and NCBI GenBank with collection dates between 1 October 2023 and 4 April 2024, ECDC concludes that no clade I sequences have been detected in Europe nor outside DRC.
Conclusion and recommendations
Despite this increase in cases, the overall risk from this outbreak in the DRC for the general population in the EU/EEA and for MSM with multiple sexual partners in the EU/EEA remains low. In line with the published threat assessment from December 2023, this is influenced by several factors, including the absence of zoonotic reservoirs for MPXV in Europe, and immunity in the MSM population due to prior infection with MPXV clade II and/or vaccination in 2022/23. However, data on clade-specific vaccine effectiveness are currently lacking, as is evidence that MPXV clade I is circulating outside certain central African countries.
Sporadic introduction of mpox in the EU/EEA connected to the ongoing DRC outbreak cannot be excluded. Public health authorities in the EU/EEA should continue preparedness and awareness activities to be able to rapidly respond in case of an introduction of MPXV clade I infection. This includes:
- Continuing efforts to raise clinician awareness about the ongoing outbreak and the possibility of travel-associated mpox cases. Awareness activities should include the possibility of different clinical presentations and more severe disease due to MPXV clade I.
- Ensuring effective surveillance, testing, and contact tracing capacities. Sequencing of samples from detected mpox cases should be performed with prompt sharing of the detected sequences.
- Continuing risk communication activities and working with civil society organisations to engage with at-risk groups.
- In the event of detection of mpox case(s) with increased severity and/or the detection of a MPXV clade I infection, this should be promptly communicated at the EU level via the alert systems EpiPulse and/or EWRS.
With emerging infectious diseases, the risks are almost always low until they aren't anymore.
With new questions regarding the ability of current PCR testing to identify this emerging clade I virus, reports of less than stellar performance from the Mpox vaccine, and a much higher fatality rate than the IIb clade, this is a virus we really don't want to see expanding its territory.
