Epidemiologic and Clinical Features of Mpox in Adults Aged >50 Years - United States, May 2022-May 2023

Estimating the burden of mpox among MSM in South Africa

Despite seeing few cases during the 2022-2023 mpox global outbreak, reports in May-July 2024 of 22 cases among men-who-have-sex-with-men (MSM) in South Africa, including three deaths, have raised concerns about under-reported community transmission. We used a Monte Carlo simulation model to estimate the true epidemic size, considering the increased severity of mpox among MSM living with advanced HIV, documented over-representation of people living with HIV among mpox cases and HIV prevalence in South Africa. We estimate that there have been between 220 and 450 cases among MSM LHIV in South Africa, with a total of 290-560 cases among all MSM. We provide an upper bound of 750-1600 cases as a sensitivity analysis where the prevalence of HIV among mpox patients is the same as population prevalence among MSM in South Africa. Estimates in both scenarios suggest a substantial number of undetected cases, with case ascertainment rates estimated between 1% and 8%. Our findings underscore the need for enhanced surveillance, targeted public health interventions and awareness campaigns to mitigate the outbreak's impact at a population level.

Dynamic Landscape of Mpox Importation Risks Driven by Heavy-Tailed Sexual Contact Networks Among Men Who Have Sex With Men in 2022

BACKGROUND

During the 2022 global mpox outbreak, the cumulative number of countries reporting their first imported case quickly rose in the early phase, but the importation rate subsequently slowed down, leaving many countries reporting no cases by the 2022 year-end.

METHODS

We developed a mathematical model of international dissemination of mpox infections incorporating sexual networks and global mobility data. We used this model to characterize the mpox importation patterns observed in 2022 and to discuss the potential of further international spread.

RESULTS

Our proposed model better explained the observed importation patterns than models not assuming heterogeneity in sexual contacts. Estimated importation hazards decreased in most countries, surpassing the global case count decline, suggesting a reduced per-case risk of importation. We assessed each country's potential to export mpox cases until the end of an epidemic, identifying countries capable of contributing to the future international spread.

CONCLUSIONS

The accumulation of immunity among high-risk individuals over highly heterogeneous sexual networks may have contributed to the slowdown in the rate of mpox importations. Nevertheless, the existence of countries with the potential to contribute to the global spread of mpox highlights the importance of equitable resource access to prevent the global resurgence of mpox.

Short-Lived Neutralizing Antibody Responses to Monkeypox Virus in Smallpox Vaccine-Naive Persons after JYNNEOS Vaccination

JYNNEOS, a third-generation smallpox vaccine, is integral to monkeypox virus (MPXV) control efforts, but the durability of this modified vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccine's effectiveness is undefined. We optimized and used a plaque reduction neutralization test (PRNT) with authentic clade IIa MPXV and vaccinia virus to assess antibody responses over 12 months in 8 donors vaccinated with 2 doses of JYNNEOS. One donor previously received the ACAM2000 vaccine; 7 donors were smallpox vaccine-naive. IgG responses of the donors to vaccinia virus (L1, B5, and A33) or MPXV (E8, H3, A35) antigens and PRNT titers to both viruses peaked at 8 weeks postvaccination and waned rapidly thereafter in naive donors. MPXV PRNT titers were especially low; no naive donors demonstrated 90% plaque reduction. These data indicate a need for improved correlates of MPXV immunity to enable MVA-BN durability studies, given that recent clinical data support MVA-BN vaccine efficacy against MPXV despite low antibody responses.

Decoding mpox: a systematic review and meta-analysis of the transmission and severity parameters of the 2022-2023 global outbreak

INTRODUCTION

The 2022-2023 mpox outbreak has been the largest in history. We aim to synthesise the key epidemiological parameters related to the dynamics, transmission, and severity of mpox (incubation period, serial interval, generation time, infectious period, basic (R0) and effective (R(t)) reproductive number, and case fatality rate (CFR)).

METHODS

Systematic review of observational studies in MEDLINE, EMBASE and other sources up to September 2023 (PROSPERO: CRD42023404503). Quality assessment using the Joanna Briggs Institute Critical Appraisal for case series, cross-sectional and cohort studies, and a designed quality assessment questionnaire for mathematical models. Meta-analysis was performed using a random effects model.

RESULTS

For transmissibility parameters, we estimated a pooled incubation period of 7.60 (95% CI 7.14 to 8.10) days and a pooled serial interval of 8.30 (95% CI 6.74 to 10.23) days. One study reported a generation time of 12.5 days (95% CI 7.5 to 17.3). Three studies reported presymptomatic transmission in 27-50% of paired cases investigated. R(t) varied between 1.16 and 3.74 and R0 varied between 0.006 and 7.84. The epidemic peaked between August and September 2022 in Europe and the Americas whereas transmission has continued in African countries. For severity parameters, we estimated a pooled CFR by continent: 0.19% (95% CI 0.09% to 0.37%) for the Americas and 0.33% (95% CI 0.15% to 0.7%) for Europe. For Africa, we found that the CFRs of countries associated with group I were higher (range 17-64%) than those associated with group IIb (range 0-6%).

CONCLUSION

Pooled mpox serial interval was slightly larger than pooled incubation period, suggesting transmission occurs mostly postsymptom onset, although presymptomatic transmission can occur in an important proportion of cases. CFR estimates varied by geographical region and were higher in Africa, in countries linked with clade I. Our results contribute to a better understanding of mpox dynamics, and the development of mathematical models to assess the impact of current and future interventions.

Mpox Cases in Serbia, 2022

BACKGROUND

On 23 July 2022, the World Health Organization (WHO) declared the mpox multi-country outbreak as a Public Health Emergency of International Concern. This study aimed to identify the epidemiological and clinical characteristics of confirmed mpox cases reported in Serbia in 2022.

METHODS

The mpox WHO case definition was used. Incidence rates (IRs) and incidence rate ratios (IRRs) by age groups and nomenclature of territorial units for statistics level 3 (NUTS-3) with 95% confidence intervals (CIs) were calculated.

RESULTS

Between June and October 2022, 43 laboratory-confirmed cases were reported. All were unvaccinated males, with the mean age of 34 (±7.4) years. Out of the total, 72.1% cases were men who have sex with men (MSM), who reported sexual intercourse either with multiple or unknown partners (p < 0.01). Fifteen cases (34.9%) lived with HIV, mostly in the 30-39 age group (p = 0.023). People living in Belgrade City NUTS-3 were six times more likely to become infected compared to South Backa citizens (IRR: 6.03, 95% CI: 1.47-25.53).

CONCLUSIONS

In Serbia, mpox mainly affected MSM aged 30-39 and living in urban areas. Health promotion and vaccine implementation should be prioritized in populations with a higher risk.

Vaccine effectiveness of 3rd generation mpox vaccines against mpox and disease severity: A systematic review and meta-analysis

INTRODUCTION

Before the global mpox outbreak which began in 2022, the real-world vaccine effectiveness (VE) of mpox vaccines was unknown. We quantified the VE in the global population of 3rd generation or later mpox vaccines (MVA-BN, LC16m8, OrthopoxVac) compared with unvaccinated or other vaccinated states for infection, hospitalization and death. VE was stratified by 1-dose and 2-doses and post-exposure prophylaxis (PEP).

METHODS

Studies were included if they measured vaccine efficacy or effectiveness in humans. Animal studies and immunogenicity studies were excluded. MEDLINE, Web of Science, Google Scholar, Embase, MedRxiv and grey literature were searched from January 1st, 1970, with the last search run on November 3, 2023 (Prospero, CRD42022345240). Risk of publication bias was assessed via funnel plots and Egger's test, and study quality via Newcastle-Ottawa scales.

RESULTS

A total of 11,892 records were identified via primary search, 3,223 via citation chasing. Thirty-three studies were identified of 3rd generation vaccines, 32 of which were MVA-BN. Two additional studies were re-analysis of existing data. Most of these studies were focused on gay, bisexual, or other men who have sex with men between the ages of 18-49 in May to October of 2022. VE of 1 dose of MVA-BN was 76% (95%CI 64-88%) from twelve studies. VE of 2 doses was 82% (95%CI 72-92%) from six studies. VE of MVA-BN PEP against mpox was 20% (95%CI -24-65%) from seven studies. All VE are calculated from random effects estimates. 18/33(55%) studies were rated as poor, 3/33(9%) as fair and 12/33(36%) as good. Studies included in the meta-analysis had higher quality: 11/16 (69%) were rated as good quality.

CONCLUSION

Both 1 and 2 doses of MVA-BN are highly effective at preventing mpox. Effectiveness estimates, specifically of PEP are limited by immortal time bias, predominant mode of mpox transmission, and real-world vaccine timing of administration.

The Risk Assessment of Uveitis After Monkeypox Diagnosis: A Multicenter Population-Based Study

The risks of uveitis development among monkeypox (MPOX) patients are unclear. To determine the uveitis risks after (MPOX) diagnosis. Population-based, retrospective cohort study used the TriNetX database and recruited those with and without MPOX diagnosis from January 1, 2016, to December 31, 2023. The non-MPOX cohort consisted of randomly selected control patients matched by covariates, including age, gender, ethnicity, race, relevant comorbidities, previous medications, and the inflammatory marker C-reactive protein. Statistical analysis on uveitis risk included hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated over 8 years (2016-2023). A separate analysis of the risk of uveitis among MPOX patients aged 20 years and older was also conducted. (MPOX) diagnosis, identified using electronic diagnostic codes. Cumulative incidence of new-onset uveitis. A total of 5449 MPOX patients of all ages (25.45% female; mean age at index 35.17 ± 15.70 years) and 5449 propensity-matched non-MPOX comparators (23.97% female; mean age at index 35.30 ± 15.91 years) were recruited from the TriNetX database. For both the overall MPOX patient population and the adult MPOX patients, the risk of uveitis was significantly higher compared to the non-MPOX cohort. This increased risk mainly happened in patients with anterior uveitis. Specifically, the hazard ratio for uveitis in all MPOX patients was 2.59 (95% CI: 1.40-4.79). Among MPOX patients aged 20 years or older, the hazard ratio for uveitis was 2.14 (95% CI: 1.17-3.94). There is a notable association between new-onset uveitis and patients with MPOX. Our real-world findings underscore the importance of being aware of the potential risk of anterior uveitis in this patient population.

Mpox in people with HIV: A narrative review

OBJECTIVE

The 2022 global mpox outbreak disproportionately impacted people living with HIV. This review explores recent evidence on mpox in this group, focusing on clinical presentation, complications, treatment modalities and vaccine strategies.

RECENT FINDINGS

Recent studies have suggested that people with HIV diagnosed with mpox have a greater risk of proctitis and hospitalization compared with people without HIV. In addition, those with advanced immunosuppression face an elevated risk of severe mpox infection, which can lead to mortality. Comprehensive and prompt supportive care using antiretrovirals and mpox antivirals is crucial in this group. Although results from randomized clinical trials are still forthcoming, recent studies suggest that early initiation of tecovirimat can prevent disease progression in people with HIV. The non-replicative attenuated smallpox vaccine is well tolerated and effective in preventing monkeypox virus infections in people with HIV. Further studies are needed regarding long-term vaccine effectiveness for this population.

CONCLUSION

Evaluating the risk of severe mpox in people living with HIV requires assessing the level of immune suppression and viral control. Universal access to vaccination is imperative to prevent the resurgence of future outbreaks.

Monkeypox virus infections in low-risk groups during the 2022-23 global outbreak: An analysis of the WHO global report

Introduction

In the 2022-23 Mpox outbreak, cases also occurred in children, adolescents, and adults aged 50 years and older, for whom the risk of transmission is low and whose epidemiological characteristics are less known, compared to high-risk groups such as young adults. Here we describe the epidemiological characteristics of Mpox in children, adolescents and adults aged 50 years and older in the global Mpox outbreak.

Methods

A retrospective study on laboratory-confirmed surveillance data of Mpox cases reported to World Health Organization (WHO) was conducted. Case data from WHO's 2022-23 Mpox Outbreak: Global Trends from 1 January 2022 to 1 September 2023 was used for our analysis. We included cases reported by WHO with data on age (children [range, 0 to 9 years], adolescents [range, 10 to 17 years], adults 50 to 59 years, and adults 60 years and older), gender, WHO region, hospital admission, and intensive care unit admission.

Results

Until September 01, 2023, data from 89,752 cases of Mpox have been reported to WHO. Of all the reported cases, 1124 (1.3%), 6296 (7.0%) and 1501 (1.6%) were children and adolescents, adults aged 50-59 years, and adults aged 60 years or older, respectively, and the proportion varied among WHO regions. There was a high proportion of cases among population aged 0-17 years, adolescents (256 [66.3%]) from the region of the Americas and girls aged 0-9 years [127 (46.7%)] from the African region. Men aged 50-59 years (3495 [57.2%] vs. 2553 [41.8%] cases from the region of the Americas and the European region, respectively) and men aged 60-69 years (639 [60.0%] vs. 607 [48.4%] from the region of the Americas and the European region) were most affected, compared to other age groups and women. Among children, adolescents, and adults aged 50 years or older, a low proportion of cases developed some complications and required hospital admission, and some cases were admitted to the intensive care unit.

Conclusions

Epidemiological evidence of Mpox in these low-risk groups highlights the risk of wider community transmission. Therefore, while efforts continue to control the global outbreak of Mpox in high-risk groups, it is also necessary to ensure that these low-risk groups have access to timely health care and vaccination.

Vaccines against mpox: MVA-BN and LC16m8

INTRODUCTION

Global outbreaks involving mpox clade IIb began in mid-2022. Today, clade IIb and clade I outbreaks continue. Reliable mpox vaccines can prevent serious mpox disease and death.

AREAS COVERED

Globally, two vaccines hold mpox indications, regardless of mpox viral clade: MVA-BN (Bavarian Nordic) and LC16m8 (KM Biologics). This review summarizes the human and pivotal animal data establishing safety and efficacy for MVA-BN and LC16m8, including real-world evidence gathered during mpox outbreaks from 2022 through 2024.

EXPERT OPINION

Some regulatory decisions for MVA-BN and LC16m8 followed pathways based on surrogate outcomes, including lethal-challenge studies in nonhuman primates, among other atypical aspects. Nonetheless, MVA-BN and LC16m8 hold unencumbered registration in multiple countries. Effectiveness of MVA-BN as primary preventive vaccination (PPV) in humans against clade IIb mpox is clear from real-world studies; effectiveness of LC16m8 against clade IIb is likely from surrogate endpoints. Effectiveness of MVA-BN and LC16m8 as PPV against more-lethal clade I is likely, based on animal-challenge studies with multiple orthopoxvirus species and other studies. Both vaccines have solid safety records. MVA-BN's replication incompetence favors adoption, whereas LC16m8 has more pediatric data. Additional real-world evidence, in additional geographic settings and special populations (e.g. pregnancy, immune suppression, atopic dermatitis), is needed.

Assessment of Knowledge and Concern of People Living with HIV Regarding Human Mpox and Vaccination

INTRODUCTION

Mpox virus is an orthopoxvirus that causes the zoonotic infectious disease known as mpox. The disease can also spread from humans to humans. It can be transmitted through contact with bodily fluids, lesions on the skin, or internal mucosal surfaces.

METHOD

The number of mpox cases increased during the COVID-19 pandemic. Early diagnosis and prompt management of mpox are critical in people living with HIV (PLHIV). In this study, a cross-sectional survey was conducted among PLHIV followed at the outpatient clinic between 20 April-20 August 2023. A questionnaire was used to assess the knowledge and anxiety levels of patients as well as their opinions about vaccination against mpox. The severity of symptoms in the past two weeks was assessed using the Generalised Anxiety Disorder 7-item scale. A total of 203 PLHIV were interviewed for this survey study.

RESULT

The mean age was 39.37±11.93. The majority of them were male (86.7%), and 41.4% were men who have sex with men (MSM). Only 21 of the surveyed participants (10.4%) had a "good knowledge" score about mpox. The mean knowledge score on human Mpox was 2.05 (min:0-max:8), and 107 (52.7%) had a score of 0.

CONCLUSION

The future study should focus on continuous education, promoting awareness through programs and establishing measures to successfully overcome identified variables that contribute to mpox pandemic understanding and attitudes. Applying the lessons learned from the COVID-19 pandemic will help the management of mpox virus.

Mpox (formerly monkeypox): pathogenesis, prevention, and treatment

In 2022, a global outbreak of Mpox (formerly monkeypox) occurred in various countries across Europe and America and rapidly spread to more than 100 countries and regions. The World Health Organization declared the outbreak to be a public health emergency of international concern due to the rapid spread of the Mpox virus. Consequently, nations intensified their efforts to explore treatment strategies aimed at combating the infection and its dissemination. Nevertheless, the available therapeutic options for Mpox virus infection remain limited. So far, only a few numbers of antiviral compounds have been approved by regulatory authorities. Given the high mutability of the Mpox virus, certain mutant strains have shown resistance to existing pharmaceutical interventions. This highlights the urgent need to develop novel antiviral drugs that can combat both drug resistance and the potential threat of bioterrorism. Currently, there is a lack of comprehensive literature on the pathophysiology and treatment of Mpox. To address this issue, we conducted a review covering the physiological and pathological processes of Mpox infection, summarizing the latest progress of anti-Mpox drugs. Our analysis encompasses approved drugs currently employed in clinical settings, as well as newly identified small-molecule compounds and antibody drugs displaying potential antiviral efficacy against Mpox. Furthermore, we have gained valuable insights from the process of Mpox drug development, including strategies for repurposing drugs, the discovery of drug targets driven by artificial intelligence, and preclinical drug development. The purpose of this review is to provide readers with a comprehensive overview of the current knowledge on Mpox.