Ending the neglect of paediatric, maternal, and congenital mpox
Authors: Nadia Adjoa Sam-Agudu, Dimie Ogoina
Journal: The Lancet Global Health (2024)

In The Lancet Global Health, Nuria Sanchez Clemente and colleagues present their global systematic review and meta-analysis on the epidemiology, prevention, and treatment of paediatric, maternal, and congenital mpox.1Sanchez Clemente N Coles C Paixao E et al.Paediatric, maternal, and congenital mpox: a systematic review and meta-analysis.Lancet Glob Health. 2024; (published online Feb 21.)https://doi.org/10.1016/S2214-109X(23)00607-1Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar Human mpox has been reported from west and central Africa since 1970 and, in these endemic settings, children younger than 18 years remain an important affected demographic. From 1970 to 2022, 39–80% of endemic mpox cases reported to WHO were 0–17-year-old children.2Sam-Agudu NA Martyn-Dickens C Ewa AU A global update of mpox (monkeypox) in children.Curr Opin Pediatr. 2023; 35: 193-200Crossref PubMed Scopus (5) Google Scholar During the 2022–23 global mpox outbreak, children and pregnant women constituted only 1·3% (1150 of 88 051) and 0·06% (54 of 87 036), respectively, of cumulative reported cases as of November, 2023.3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar In the same timeframe, African mpox cases constituted 2% of global but at least 30% of all paediatric cases.3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar The global outbreak triggered a surge in mpox research and vaccine development, especially in highly resourced, non-endemic countries. Unfortunately, the availability of rigorous data on paediatric mpox epidemiology, prevention, treatment, and case fatality continues to be limited, particularly in endemic African countries.2Sam-Agudu NA Martyn-Dickens C Ewa AU A global update of mpox (monkeypox) in children.Curr Opin Pediatr. 2023; 35: 193-200Crossref PubMed Scopus (5) Google Scholar, 3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar, 4Africa Centres for Disease Control and PreventionDisease outbreaks: mpox.https://africacdc.org/disease-outbreak/Date: 2023Date accessed: January 22, 2024Google Scholar To help narrow this data gap, Sanchez Clemente and colleagues systematically identified and analysed 61 mpox studies conducted in ten endemic African and six non-endemic countries between 1972 and 2023.1Sanchez Clemente N Coles C Paixao E et al.Paediatric, maternal, and congenital mpox: a systematic review and meta-analysis.Lancet Glob Health. 2024; (published online Feb 21.)https://doi.org/10.1016/S2214-109X(23)00607-1Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar Included studies comprised outbreak and case reports, case series, and surveillance and observational studies. 53 studies reported on 2123 children aged 18 years and younger, out of which 39 studies reported on individual outcomes for only 101 children; viral clade was available for just six (7%) of 89 endemic and four (33%) of 12 non-endemic cases. Seven studies described maternal or congenital outcomes from 32 cases (75% from the USA, no deaths reported). Two studies reported on the use of live, non-replicating vaccine for 28 children during mpox outbreaks in the UK and USA with no reported side-effects or mpox development, and six observational studies described well tolerated tecovirimat treatment among 21 children and 12 pregnant women. The authors noted the absence of published randomised controlled trial findings on safety or efficacy for any mpox vaccine or therapeutic agent in these populations. Despite the absence of randomised trials and the low number of paediatric and pregnant cases or study participants, this analysis generated some key findings: the top three clinical features of paediatric mpox (74 [86%] of 86 analysed cases from endemic countries) were: rash (100%), fever (73%), and lymphadenopathy (47%); the pooled case fatality ratio (CFR) estimate for paediatric mpox was 11% (95% CI 4–20); the most common cause of complications in paediatric mpox was secondary bacterial infection; and available data showed a 50% fetal loss rate in 12 mpox-affected pregnancies. Data from endemic countries have established that clade 1 (previously Congo Basin or central African clade) mpox infections have a higher CFR (around 11%) than clade 2 (previously west African clade; <1% to around 4%).5Sklenovská N Van Ranst M Emergence of monkeypox as the most important orthopoxvirus infection in humans.Front Public Health. 2018; 6: 241Crossref PubMed Google Scholar, 6Bunge EM Hoet B Chen L et al.The changing epidemiology of human monkeypox—a potential threat? A systematic review.PLoS Negl Trop Dis. 2022; 16e0010141Crossref PubMed Scopus (909) Google Scholar The CFR for the 2022 clade 2b global outbreak is approximately 0·2%.3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar Beyond mpox virus subtype, Sanchez Clemente and colleagues note the lack of evidence on the contribution of concurrent and sequential infections (eg measles, chickenpox,7Mmerem JI Umenzekwe CC Johnson MS et al.Mpox and chickenpox co-infection: case series from southern Nigeria.J Infect Dis. 2023; (published online Dec 7.)https://doi.org/10.1093/infdis/jiad556Crossref PubMed Google Scholar HIV,8Yinka-Ogunleye A Dalhat M Akinpelu A et al.Mpox (monkeypox) risk and mortality associated with HIV infection: a national case-control study in Nigeria.BMJ Glob Health. 2023; 8e013126Crossref PubMed Google Scholar and malaria) to poor paediatric and maternal mpox outcomes.1Sanchez Clemente N Coles C Paixao E et al.Paediatric, maternal, and congenital mpox: a systematic review and meta-analysis.Lancet Glob Health. 2024; (published online Feb 21.)https://doi.org/10.1016/S2214-109X(23)00607-1Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar Other knowledge gaps remain, including: paediatric and maternal mpox CFR in endemic versus non-endemic countries; the epidemiology and clinical outcomes of clade 1 versus clade 2 subtype infections in paediatric and pregnant populations; rates and risk factors for hospitalisation, long hospital stay, severe disease, and death; maternal and fetal risk factors for congenital mpox; and safe and effective therapeutics for maternal and pediatric mpox prevention and treatment. WHO declared the mpox pandemic over on May 11, 2023. Reported cases have continued to decline substantially, from a peak of more than 30 000 monthly cases in August, 2022, to an average of fewer than 850 monthly cases as of November, 2023.3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar Nonetheless, endemic African countries continue to report cases, particularly from DR Congo, which experienced a large clade 1 outbreak starting in March, 2023, that was linked, for the first time, to sexual contact.9Kibungu EM Vakaniaki EH Kinganda-Lusamaki E et al.Clade I-associated mpox cases associated with sexual contact, the Democratic Republic of the Congo.Emerg Infect Dis. 2024; 30: 172-176Crossref PubMed Scopus (8) Google Scholar As of November, 2023, WHO reports nearly 14 000 suspected cases and 607 deaths in 2023 for DR Congo, with children younger than 15 years comprising 70% of suspected cases and deaths.3WHO2022–23 mpox (monkeypox) outbreak: global trends.https://worldhealthorg.shinyapps.io/mpx_global/#2_Global_situation_updateDate: 2024Date accessed: January 27, 2024Google Scholar Given the downward trend of the global outbreak, we find it prudent for large studies on mpox to focus on endemic countries and prioritise paediatric and pregnant populations. The analysis by Sanchez Clemente and colleagues adds much-needed evidence to an mpox data vacuum. However, as the authors rightly stated, "(t)he scope of the results is limited by the availability and quality of the datasets that have been published."1Sanchez Clemente N Coles C Paixao E et al.Paediatric, maternal, and congenital mpox: a systematic review and meta-analysis.Lancet Glob Health. 2024; (published online Feb 21.)https://doi.org/10.1016/S2214-109X(23)00607-1Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar The mpox pandemic might be declared over, but mpox remains an important infectious disease of public health concern, especially in west and central Africa. We call for sustained investments in multi-country clinical trials and rigorous observational studies prioritising paediatric and maternal mpox to further address this longstanding data vacuum. NAS-A reports funding from the European Commission to her institution to conduct mpox studies in Nigeria. DO declares no competing interests. Paediatric, maternal, and congenital mpox: a systematic review and meta-analysisOur review highlights critical knowledge gaps in the epidemiology, prevention, and treatment of mpox in children and pregnant individuals, especially those residing in endemic countries. Increased funding, international collaboration, and equitable research is needed to inform mpox control strategies tailored for at-risk communities in endemic countries. Full-Text PDF Open Access