Re-emergence of Mpox associated with a distinct MPXV clade: implications for public health and stigma mitigation

To the Editor,

We read with great interest the manuscript by Paparini and colleagues, in which they synthesised the available evidence on preventive behavioural interventions aimed at reducing sexual acquisition of mpox, onward sexual transmission from confirmed or probable cases, and the utility of asymptomatic testing through a systematic review of the literature [1]. The authors concluded that evidence on the effectiveness of interventions to prevent the sexual transmission of mpox remains limited and advocate for other effective preventive measures that are acceptable to communities at risk of mpox in various contexts. This is of paramount importance considering the ongoing mpox outbreak in the Democratic Republic of Congo (DRC), which began in the autumn of 2023 and is escalating. Sexual contact appears to play a significant role in this outbreak, posing new challenges and raising public health concerns [2]. This outbreak is attributed to a new lineage of the Monkeypox Virus (MPXV), Clade Ib, distinct from previously sequenced Clade I strains [3,4].

In 2022, a global mpox outbreak, primarily involving men who have sex with men (MSM), resulted in approximately 85,000 cases, affecting non-endemic regions such as the United States and Europe. Commons symptoms included fever, a rash predominantly in the anogenital region, and lymphadenopathy, with a case fatality rate (CFR) of approximately 0.2%. In contrast, since 1970, mpox in endemic countries primarily affected children and young men through zoonotic transmission, with human-to-human transmission limited to intrafamilial and occupational settings with a CFR of up to 10-15% [5,6].

The 2022 outbreak strain, classified as Clade IIb, was mainly associated with sexual intercourse and predominantly affected gay, bisexual, and other MSM (GBMSM) [7]. Despite the attempt to normalise mpox as part of STIs services, a drawing attention to homophobic stereotypes contributed to stigma. GBMSM reported receiving an mpox diagnosis as traumatic, with inconsistent information about the illness, isolation, and vaccination [8]. In the current DRC outbreak evidence indicates that the virus is now largely transmitted through sexual contact and is expanding in previously unaffected urban areas, resembling Clade II MPXV behaviour [2,3]. Vakaniaki et al. found that most patients diagnosed with Clade Ib MPXV in the DRC are female, with a large proportion being sex workers, mainly adolescents and young adults [3]. Approximately 85% of these patients presented with genital lesions. Interviews with confirmed cases revealed that 88% had physical contact with another MPXV-infected patient, 59% of whom specifically reported sexual contact [3]. Of note, during the 2022 outbreak, similar proportions of reported sexual contact were observed by Thornhill et al. in cisgender and transgender women, with 74% overall, 61% among cis women and non-binary individuals [9]. Smallpox vaccination is expected to offer a good level of protection against mpox [10]. However, Clade Ib MPXV is reportedly spreading among unvaccinated individuals, highlighting the effect of global inequities in vaccines distribution. In conclusion, the outbreak in the DRC underscores the urgency of addressing mpox epidemiology and dynamics, improving surveillance, case management, and vaccination systems [2,11]. Efforts to control the spread of mpox must avoid perpetuating stigma and discrimination, particularly against vulnerable groups such as sexual and gender minorities.

Disclosure statement

The authors declare no competing interests.