Monkeypox: a review of epidemiological modelling studies and how modelling has led to mechanistic insight

"I Know They're Going to Weaponize This:" Black and Latino Sexual Minority Men's Mpox-Related Sexual Behaviors, Stigma Concerns, and Vaccination Barriers and Facilitators

BACKGROUND

The Mpox epidemic disproportionately impacted Black and Latino sexual minority men (BLSMM) in the United States, with them having the highest prevalence of disease and the lowest rates of vaccination. Despite this disparity, BLSMM perspectives on the disease, Mpox-related stigma, and inequitable rollout of and distrust in the Mpox vaccine are absent from the literature. The present study aims to describe experiences with Mpox-related sexual behaviors, stigma, and vaccine barriers and facilitators among a sample of BLSMM living in both California and New York.

METHODS

In this qualitative interpretive phenomenological study, we utilized semi-structured individual interviews as the primary source for data collection. Data was collected between August 2021 and December 2022 from 41 adult participants in California and New York. Interviews were recorded, transcribed verbatim, and analyzed using thematic content analysis.

RESULTS

Participants ranged in age from 19 to 65 years, with the majority identifying as Black (73%) and male gender (93%). Overall, participants' narratives revealed that initial messaging around Mpox produced stigma parallel to the HIV/AIDS pandemic with many participants curtailing their sexual behaviors as a harm reduction strategy. Mpox-related stigma negatively impacted sexual minority communities both internally and externally. Participants' narratives also revealed general vaccine skepticism due to existing medical distrust, negative vaccine experiences by other BLSMM, and lack of prioritization of outreach and distribution efforts in communities of color.

CONCLUSION

Alterations to vaccine administration protocols and outreach efforts for reasons identified in this study are critical to addressing disparities in vaccine uptake among BLSMM. Public health practitioners must consider equitable frameworks, existing stigmas, and medical distrust when engaging BLSMM.

Machine Learning Reveals Distinct Immunogenic Signatures of Th1 Imprinting in ART-Treated Individuals with HIV Following Repeated SARS-CoV-2 Vaccination

The human immune system is intrinsically variable and remarkably diverse across a population. The immune response to antigens is driven by a complex interplay of time-dependent interdependencies across components of the immune system. After repeated vaccination, the humoral and cellular arms of the immune response display highly heterogeneous dynamics, further complicating the attribution of a phenotypic outcome to specific immune system components. We employ a random forest (RF) approach to classify informative differences in immunogenicity between older people living with HIV (PLWH) on ART and an age-matched control group who received up to five SARS-CoV-2 vaccinations over 104 weeks. RFs identify immunological variables of importance, interpreted as evidence for Th1 imprinting, and suggest novel distinguishing immune features, such as saliva-based antibody screening, as promising diagnostic features towards classifying responses (whereas serum IgG is not). Additionally, we implement supervised and unsupervised Machine Learning methods to produce physiologically accurate synthetic datasets that conform to the statistical distribution of the original immunological data, thus enabling further data-driven hypothesis testing and model validation. Our results highlight the effectiveness of RFs in utilizing informative immune feature interdependencies for classification tasks and suggests broad impacts of ML applications for personalized vaccination strategies among high-risk populations.

Investigating Mpox Strain Dynamics Using Computational and Data-Driven Approaches

This study explores Mpox transmission dynamics using a mathematical and data-driven epidemiological model that incorporates two viral strains, Clade I and Clade II. The model includes transmission pathways between humans and mammals and divides the human population into susceptible, exposed, infectious, hospitalized, and recovered groups. Weekly data from the WHO for Spain, Italy, Nigeria, and the DRC from 2022 to 2024 are used for model validation via non-linear least-squares fitting, with model performance assessed by Root Mean Squared Error (RMSE). We conduct time-series analysis to detect trends and anomalies in Mpox cases, with scenario simulations examining strain-specific transmission and the basic reproduction number (R0). The mathematical model fit is compared with two statistical model fits to emphasize the importance of developing a model that incorporates Mpox strain. Mathematical analysis confirms the model's key properties, including positivity, boundedness, and equilibrium stability. Results underscore the importance of strain-specific dynamics and varying infection proportions for R0. This study combines mathematical rigor with empirical data to provide valuable insights into Mpox transmission and offers a framework for understanding multi-strain pathogens in diverse populations. Results from the simulation indicate that an increase in the effective contact rate leads to the dominance of the prevalent Mpox Clades in each country. Based on these findings, we recommend the implementation of strategies aimed at reducing the effective contact rate to control the spread of the virus strains.

Clade Ib: a new emerging threat in the Mpox outbreak

Monkeypox, a zoonotic virus in the Orthopoxvirus genus, has drawn global attention for its impact on public health. In the current Mpox outbreak, a novel clade, Ib, has emerged as a significant and potentially fatal threat. This review examines the dynamics of MPXV transmission, person-to-person spread, and infection mechanisms, highlighting key risk factors. We explore the clinical features of Mpox, focusing on symptomology, illness duration, and the distinguishing characteristics of clade Ib compared to other clades. A critical analysis addresses diagnostic techniques and emphasizes the need for robust surveillance, particularly for clade Ib detection. We review recent prevention and treatment strategies, including antiviral drugs and vaccines, with a focus on clade Ib containment. The conclusion underscores the urgency of global collaboration to prevent and prepare for emerging threats like clade Ib and identifies crucial research paths and knowledge gaps. This review offers a comprehensive overview of clade Ib, covering its emergence, genetic traits, epidemiological impact, transmission patterns, clinical features, the role of Artificial Intelligence (AI) in outbreak management, detection challenges, and implications for public health response.

Social dilemma of nonpharmaceutical interventions: Determinants of dynamic compliance and behavioral shifts

In fighting infectious diseases posing a global health threat, ranging from influenza to Zika, nonpharmaceutical interventions (NPI), such as social distancing and face covering, remain mitigation measures public health can resort to. However, the success of NPI lies in sufficiently high levels of collective compliance, otherwise giving rise to recurrent infections that are not only driven by pathogen evolution but also changing vigilance in the population. Here, we show that compliance with each NPI measure can be highly dynamic and context-dependent during an ongoing epidemic, where individuals may prefer one to another or even do nothing, leading to intricate temporal switching behavior of NPI adoptions. By characterizing dynamic regimes through the perceived costs of NPI measures and their effectiveness in particular regarding face covering and social distancing, our work offers insights into overcoming barriers in NPI adoptions.

Navigating monkeypox: identifying risks and implementing solutions

Monkeypox is a zoonotic disease caused by the orthopox virus, a double-stranded DNA virus that belongs the Poxviridae virus family. It is known to infect both animals (especially monkeys and rodents) and humans and causes a rash similar to smallpox. Humans can become infected with monkeypox virus (MPXV) when they get in close contact with infected animals (zoonotic transmission) or other infected people (human-human transmission) through their body fluids such as mucus, saliva, or even skin sores. Frequently observed symptoms of this disease include fever, headaches, muscle aches, and a rash that initially looks like a tiny bump before becoming a lump that is filled with fluid. Monkeypox symptoms also include an incubation period of 5-21 days, divided into prodromal and eruption phases. Several contributing factors, such as smallpox vaccine discontinuation, widespread intake of infected animal products as a source of protein, and high population density, amongst others, have been linked to an increase in the frequency of monkeypox outbreaks. The best course of action for diagnosing individuals who may be suffering from active monkeypox is to collect a sample of skin from the lesion and perform PCR molecular testing. Monkeypox does not presently have a specific therapy; however, supportive care can assist in managing symptoms, such as medication to lower body temperature and pain. Three major orthopoxvirus vaccines have been approved to serve as a preventive measure against monkeypox: LC16, JYNNEOS, and ACAM2000. The discovery that the monkeypox outbreak is communicable both among humans and within a population has sparked new public health worries on the possibility of the outbreak of another viral pandemic. Research and studies are still being conducted to gain a deeper understanding of this zoonotic viral disease. This review is therefore focused on deciphering monkeypox, its etiology, pathogenesis, transmission, risk factors, and control.

Modelling vaccination approaches for mpox containment and mitigation in the Democratic Republic of the Congo

BACKGROUND

Mpox was first identified in the Democratic Republic of the Congo (DRC) in 1970. In 2023, a historic outbreak of mpox occurred in the country, continuing into 2024. Over 14 000 cases and 600 deaths were reported in 2023 alone, representing a major increase from previous outbreaks. The modified vaccinia Ankara vaccine (brand names JYNNEOS, Imvamune, and Imvanex) was used in the 2022 mpox outbreak in the USA and Europe. However, at the time of the study, vaccination had not been made available in the DRC. We aimed to inform policy and decision makers on the potential benefits of, and resources needed, for mpox vaccination campaigns in the DRC by providing counterfactual scenarios evaluating the short-term effects of various vaccination strategies on mpox cases and deaths, if such a vaccination campaign had been undertaken before the 2023-24 outbreak.

METHODS

A dynamic transmission model was used to simulate mpox transmission in the DRC, stratified by age (<5, 5-15, and >15 years) and province. The model was used to simulate potential vaccination strategies, varying by age and region (endemic provinces, non-endemic provinces with historic cases, and all provinces) assessing the effect the strategies would have on deaths and cases in an epidemic year similar to 2023. In addition, we estimated the number of vaccine doses needed to implement each strategy.

FINDINGS

Without vaccination, our model predicted 14 700 cases and 700 deaths from mpox over 365 days. Vaccinating 80% of all children younger than 5 years in endemic regions led to a 27% overall reduction in cases and a 43% reduction in deaths, requiring 10·5 million vaccine doses. Vaccinating 80% of all children younger than 5 years in all regions led to a 29% reduction in cases and a 43% reduction in deaths, requiring 33·1 million doses. Vaccinating 80% of children aged 15 years or younger in endemic provinces led to a 54% reduction in cases and a 71% reduction in deaths, requiring 26·6 million doses.

INTERPRETATION

When resources are limited, vaccinating children aged 15 years or younger, or younger than 5 years, in endemic regions of the DRC would be the most efficient use of vaccines. Further research is needed to explore long-term effects of a one-time or recurrent vaccination campaign.

FUNDING

Canadian Institutes of Health Research, Canadian International Development Research Centre, US Department of Defense (Defense Threat Reduction Agency, Mpox Threat Reduction Network), Global Affairs Canada (Weapons Threat Reduction Program), US Department for Agriculture (Agriculture Research Service, Non-Assistance Cooperative Agreement).

Mpox in sports: A comprehensive framework for anticipatory planning and risk mitigation in football based on lessons from COVID-19

The World Health Organization's declaration of mpox (formerly known as monkeypox) as a public health emergency of international concern (PHEIC) in July 2022, followed by its resurgence in 2024, has sparked concerns about its potential impact on sports, especially contact sports such as football. Although mpox is not a pandemic (as of late September 2024), the coronavirus disease 2019 (COVID-19) experience offers valuable lessons for proactive planning in sports. Our conceptual framework has been designed to draw insightful lessons from the COVID-19 pandemic to assist sports organizations in planning for and preventing similar situations. We aimed to draw lessons from COVID-19 to help sports organizations enhance practical preparedness through effective planning and mitigation strategies. Accordingly, we sought to assess the potential impact of mpox on sports, with a focus on football (soccer), and to develop strategies for prevention, management, and preparedness based on epidemiological insights and lessons from COVID-19 pandemic experience. Here we review mpox's pathophysiology and possibility of transmission in sports settings and discuss tailored strategies, including risk assessments, testing protocols, hygiene measures, and return-to-play policies. This review highlights key differences between mpox and COVID-19 in transmission, incubation, and management, emphasizing the need for customized prevention and control measures in sports. We propose innovative risk assessment methods using global positioning system tracking and machine learning for contact analysis, alongside tailored testing and hygiene protocols. We emphasize the importance of proactive planning, noting improved preparedness in the sports community compared to the early days of COVID-19. In conclusion, our proposed framework provides sports organizations with practical tools to manage potential risks associated with mpox, ensuring the continuity of activities while prioritizing public health.

Performance analysis of mathematical methods used to forecast the 2022 New York City Mpox outbreak

In mid-2022, New York City (NYC) became the epicenter of the US mpox outbreak. We provided real-time mpox case forecasts to the NYC Department of Health and Mental Hygiene to aid in outbreak response. Forecasting methodologies evolved as the epidemic progressed. Initially, lacking knowledge of at-risk population size, we used exponential growth models to forecast cases. Once exponential growth slowed, we used a Susceptible-Exposed-Infectious-Recovered (SEIR) model. Retrospectively, we explored if forecasts could have been improved using an SEIR model in place of our early exponential growth model, with or without knowing the case detection rate. Early forecasts from exponential growth models performed poorly, as 2-week mean absolute error (MAE) grew from 53 cases/week (July 1-14) to 457 cases/week (July 15-28). However, when exponential growth slowed, providing insight into susceptible population size, an SEIR model was able to accurately predict the remainder of the outbreak (7-week MAE: 13.4 cases/week). Retrospectively, we found there was not enough known about the epidemiological characteristics of the outbreak to parameterize an SEIR model early on. However, if the at-risk population and case detection rate were known, an SEIR model could have improved accuracy over exponential growth models early in the outbreak.

Mpox: An Overview of Pathogenesis, Diagnosis, and Public Health Implications

Mpox, caused by viruses of the genus Orthopoxvirus, is an emerging threat to human and animal health. With increasing urbanization and more frequent interaction between humans and wild animals, the risk of Mpox transmission to humans has increased significantly. This review aims to examine in depth the epidemiology, pathogenesis, and diagnosis of Mpox, with a special focus on recent discoveries and advances in understanding the disease. Molecular mechanisms involved in viral replication will be examined, as well as risk factors associated with interspecific transmission and spread of the disease in human populations. Currently available diagnostic methods will also be discussed, with a critical analysis of their limitations and possible future directions for improving the accuracy and timeliness of diagnosis. Finally, this review will explore the public health implications associated with Mpox, emphasizing the importance of epidemiological surveillance, vaccination, and emergency preparedness to prevent and manage possible outbreaks. Understanding the epidemiology and control strategies for Mpox is critical to protecting the health of human and animal communities and mitigating the risk of interspecific transmission and spread of the disease.

Characteristics of the Sexual Networks of Men Who Have Sex With Men in Montréal, Toronto, and Vancouver: Insights from Canada's 2022 Mpox Outbreak

BACKGROUND

The 2022-2023 global mpox outbreak disproportionately affected gay, bisexual, and other men who have sex with men (GBM). We investigated differences in GBM's sexual partner distributions across Canada's 3 largest cities and over time, and how they shaped transmission.

METHODS

The Engage Cohort Study (2017-2023) recruited GBM via respondent-driven sampling in Montréal, Toronto, and Vancouver (n = 2449). We compared reported sexual partner distributions across cities and periods: before COVID-19 (2017-2019), pandemic (2020-2021), and after lifting of restrictions (2021-2023). We used Bayesian regression and poststratification to model partner distributions. We estimated mpox's basic reproduction number (R0) using a risk-stratified compartmental model.

RESULTS

Pre-COVID-19 pandemic distributions were comparable: fitted average partners (past 6 months) were 10.4 (95% credible interval: 9.4-11.5) in Montréal, 13.1 (11.3-15.1) in Toronto, and 10.7 (9.5-12.1) in Vancouver. Sexual activity decreased during the pandemic and increased after lifting of restrictions, but remained below prepandemic levels. Based on reported cases, we estimated R0 of 2.4 to 2.7 and similar cumulative incidences (0.7%-0.9%) across cities.

CONCLUSIONS

Similar sexual partner distributions may explain comparable R0 and cumulative incidence across cities. With potential for further recovery in sexual activity, mpox vaccination and surveillance strategies should be maintained.