Monkeypox vaccination in the global south: Fighting a war without a weapon

Understanding the resurgence of mpox: key drivers and lessons from recent outbreaks in Africa

Mpox has re-emerged as a significant public health threat, particularly in Africa. This study explores the key drivers behind the recent resurgence, focusing on epidemiological trends, transmission dynamics, and lessons learned from recent outbreaks. The research involved a comprehensive review of recent mpox outbreaks, analyzing factors, such as socio-economic conditions, environmental influences, and genetic evolution. Findings indicate that the resurgence is linked to the cessation of smallpox vaccination, increased human-wildlife interactions, and rapid urbanization in endemic regions. The virus, which was previously confined to rural areas, has now spread to urban populations, and crossed national borders, driven by high population mobility and socio-economic instability. A notable shift in transmission dynamics has been observed, with increased human-to-human transmission, particularly among men who have sex with men (MSM), contributing to more severe and widespread outbreaks. The study highlights the urgent need to strengthen health systems in Africa, particularly in the areas of diagnostics, surveillance, and public health preparedness. Challenges such as inadequate laboratory infrastructure and delayed response mechanisms have exposed vulnerabilities in current public health frameworks. To prevent future outbreaks, targeted strategies must be implemented, including enhanced community engagement, improved access to vaccines and treatments, and timely, accurate reporting of cases. Coordinated global action is essential to prevent mpox from becoming a more persistent and widespread public health threat. This research discusses the importance of proactive measures and international cooperation in addressing the ongoing threat posed by mpox, particularly in regions with limited healthcare resources.

Current advances and challenges in mpox vaccine development: a global landscape

Given the surge in mpox outbreaks in 2022 and the advancements in domestic and international vaccine research, the effectiveness of smallpox vaccines in providing cross-protection against mpox remains crucial. Having learned from the COVID-19 pandemic, it is significant to continue evaluating existing vaccines to ensure their safety and efficacy. Developing new vaccines for widespread use against mpox and its emerging strains also serves as a preventive strategy in the ongoing battle against this dynamic infection. Here's an opportunity to control human-to-human transmission, give short deadlines, and avoid vaccine disparity. Public health systems must take decisive action to prevent the global spread of mpox, particularly among vulnerable groups. This action should include strengthening global surveillance, improving vaccine access, and ensuring equitable distribution, particularly in resource-poor settings, to prevent future outbreaks. This review aims to assess recent advancements and barriers in mpox vaccine development, emphasizing cross-protection and equitable vaccine distribution in resource-poor settings.

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).

Challenges in Global Distribution and Equitable Access to Monkeypox Vaccines

The monkeypox outbreak has grown beyond the regions in which it was considered endemic. It has spread from central and west Africa to non-endemic regions like Europe, America, and other parts of the world. It has recently been classified as a public health emergency of international concern. This study evaluated the challenges faced globally and equitable access to monkeypox vaccines. Global competition has been observed in the race to obtain vaccines, with low- and middle-income countries being disadvantaged. Great inequity exists in the distribution of vaccines globally through advance purchase agreements, vaccine stockpiling, vaccine nationalism, the inequitable distribution of existing resources, and insufficient surveillance and reporting mechanisms. To address some of these challenges, there is a need for strengthening the global vaccine manufacturing capacity, targeting countries with elevated risk profiles and limited resources, strengthening surveillance systems, and addressing vaccine hesitancy.

Mpox and Lessons Learned in the Light of the Recent Outbreak: A Narrative Review

According to the WHO, more than 90,000 cases of mpox have been reported since the 2022 worldwide outbreak, which resulted in 167 deaths, while a new outbreak in Africa since 2023 has resulted in over 18,000 cases and 617 deaths. Mpox is a zoonosis caused by the monkeypox virus, a double-stranded DNA virus belonging to the Orthopoxvirus genus, which causes smallpox-like illness. Until 2022, cases were predominately located in West and Central Africa, with only sporadic cases and outbreaks reported in other parts of the world. During the 2022 outbreak, the primary mode of transmission was sexual contact among men who have sex with men. The changing epidemiology of mpox resulted in new disease phenotypes and populations at risk, disproportionally affecting people who live with HIV. Commonly presenting as a mild, self-limiting illness, mpox can cause severe and protracted disease in people with HIV with a CD4 count < 200 cell/mm3. The global emergence of mpox that followed and intersected with COVID-19 mobilized the scientific community and healthcare stakeholders to provide accurate diagnostics, preventive vaccines and treatment to those most affected. Despite existing gaps, this rapid response helped to contain the outbreak, but challenges remain as new variants emerge. Preparedness and readiness to respond to the next outbreak is crucial in order to minimize the impact to the most vulnerable.

Mpox in East Africa: Learning from COVID-19 and Ebola to Strengthen Public Health Responses

The Africa Centers for Disease Control and Prevention declared mpox a Public Health Emergency of Continental Security (PHECS) in Africa. African public health systems have moved to mobilize a response against a backdrop of inherent significant challenges. With this commentary, we discuss how lessons from past public health emergencies, particularly COVID-19 and Ebola outbreaks, have prepared the region for improved disease surveillance, rapid response strategies, and effective public health communication and how these lessons can be applied to the mpox response, emphasizing the importance of strong healthcare infrastructure, effective data sharing, community engagement, targeted interventions, and robust contact tracing. Additionally, addressing misinformation and building public trust are crucial for controlling the spread of any disease. By leveraging these strategies, African countries can enhance their response to mpox. This includes improving diagnostic capabilities, strengthening cross-border collaborations, and prioritizing vaccination campaigns where needed. Ultimately, by applying the hard-earned lessons from the COVID-19 pandemic and Ebola outbreak, the East Africa region can better address the challenges posed by mpox and safeguard public health.

A critical review of mpox outbreaks, risk factors, and prevention efforts in Africa: lessons learned and evolving practices

OBJECTIVES

In recent years, mpox, a zoonotic disease caused by the mpox virus, has transcended its primary association with Central and West Africa, emerging as a global public health concern. The virus poses a substantial threat, particularly, to vulnerable demographics such as young children and individuals with compromised immune systems. This critical literature review aimed to comprehensively evaluate the burden, risk factors, and current management strategies associated with mpox in Africa.

METHODS

This critical literature review was guided by Jesson & Laccy's guidelines on conducting critical literature reviews. We searched PubMed and Google Scholar databases and websites of the World Health Organization and health ministries in different African countries. We included articles written in English and published between 2010 and 2023. The synthesis of findings involved several steps, including summarizing themes, integrating themes, and linking themes to research questions.

RESULTS

A total of 25 articles were included in this review. The review revealed that mpox cases are concentrated in Central African countries. The risk factors for mpox identified include being in contact with bushmeat or rodents, not having been vaccinated against smallpox, being HIV-positive, and having close physical contact with someone with the disease. The clinical presentation of mpox revealed in this review includes a skin rash, fever, lymphadenopathy, headache, pruritus, sore throat, and body aches. Four themes arose on strategies to prevent and control mpox in Africa.

CONCLUSIONS

The prevention and control of mpox in Africa require an improvement in community education, vaccination, disease surveillance, and infection control measures.

Exploring the dynamics of monkeypox transmission with data-driven methods and a deterministic model

Introduction

Mpox (formerly monkeypox) is an infectious disease that spreads mostly through direct contact with infected animals or people's blood, bodily fluids, or cutaneous or mucosal lesions. In light of the global outbreak that occurred in 2022-2023, in this paper, we analyzed global Mpox univariate time series data and provided a comprehensive analysis of disease outbreaks across the world, including the USA with Brazil and three continents: North America, South America, and Europe. The novelty of this study is that it delved into the Mpox time series data by implementing the data-driven methods and a mathematical model concurrently-an aspect not typically addressed in the existing literature. The study is also important because implementing these models concurrently improved our predictions' reliability for infectious diseases.

Methods

We proposed a traditional compartmental model and also implemented deep learning models (1D- convolutional neural network (CNN), long-short term memory (LSTM), bidirectional LSTM (BiLSTM), hybrid CNN-LSTM, and CNN-BiLSTM) as well as statistical time series models: autoregressive integrated moving average (ARIMA) and exponential smoothing on the Mpox data. We also employed the least squares method fitting to estimate the essential epidemiological parameters in the proposed deterministic model.

Results

The primary finding of the deterministic model is that vaccination rates can flatten the curve of infected dynamics and influence the basic reproduction number. Through the numerical simulations, we determined that increased vaccination among the susceptible human population is crucial to control disease transmission. Moreover, in case of an outbreak, our model showed the potential for epidemic control by adjusting the key epidemiological parameters, namely the baseline contact rate and the proportion of contacts within the human population. Next, we analyzed data-driven models that contribute to a comprehensive understanding of disease dynamics in different locations. Additionally, we trained models to provide short-term (eight-week) predictions across various geographical locations, and all eight models produced reliable results.

Conclusion

This study utilized a comprehensive framework to investigate univariate time series data to understand the dynamics of Mpox transmission. The prediction showed that Mpox is in its die-out situation as of July 29, 2023. Moreover, the deterministic model showed the importance of the Mpox vaccination in mitigating the Mpox transmission and highlighted the significance of effectively adjusting key epidemiological parameters during outbreaks, particularly the contact rate in high-risk groups.

Human Mpox in People Living with HIV: Epidemiologic and Clinical Perspectives from Nigeria

Sub-Saharan Africa (SSA) is disproportionately affected by mpox and HIV. We described epidemiologic trends and clinical experiences in the management of mpox in people living with HIV (PLWH) in Nigeria and further examined how the rapidly accumulating body of knowledge from the 2022 global mpox outbreak might be explored to improve mpox care in PLWH in SSA. During the 2017/2018 Nigerian mpox outbreak, we reported that 9/40 (22.5%) hospitalized mpox patients with known HIV status were PLWH. In the 2022 global mpox outbreak, 52% of confirmed mpox cases with known HIV status were PLWH, predominantly sexual and gender minority groups. However, substantial missing data on HIV status of confirmed mpox cases highlights a critical gap in HIV testing as a component of mpox management. Before 2022, sexual activity was not commonly linked to mpox transmission, but this was identified as a major driver of transmission during the 2022 mpox outbreak. Notable sexual history observed in Nigerian mpox patients in 2017/2018 suggests that the contribution of sexual activity in human-to-human mpox transmission might have been underappreciated for years. Our cohort of PLWH with mpox, predominantly individuals with advanced or uncontrolled HIV, were significantly more likely to experience severe mpox manifestations and prolonged disease compared with those without HIV. This contrasts with the generally less remarkable differences in mpox presentation between people with and without HIV in Western countries, an observation that can be at least partially explained by more stable HIV disease. The unavailability of mpox antiviral drugs and vaccines in SSA highlights global inequity in mpox response, which requires an urgent attention. As mpox countermeasures become available in SSA, lessons learned from their use in Western countries could provide important guidance for care providers in SSA. Public health measures to mitigate stigmatization in PLWH with mpox is also critical.

Mpox vaccination for men who have sex with men and their differential risk of exposure and infection

Following the post-COVID-19 reopening of the society with enhanced traveling between countries, people at risk of mpox infection, notably men who have sex with men (MSM) and people living with HIV, are facing increasing threat of virus exposure. Mpox vaccination is an important public health strategy which is provided free in Hong Kong to people at higher risk of infection. Between October 2022 and January 2023, 326 and 184 MSM vaccinees from vaccination sites and HIV specialist clinics in Hong Kong, respectively, were recruited for assessing their infection risks. Apart from the urge to protect one's significant others (68%), 45% were worried about the stigmatizing mpox symptoms if infected. Compared with MSM vaccinees at vaccination site, a lower proportion of MSM vaccinees in HIV care were sexually active in the past 6 months (88% vs 97%), but a higher proportion had recent sexually transmitted infection diagnoses (19% vs 10%) and perceived considerable exposure risk in the following 6 months (40% vs 22%). There were no differences in the perceived effectiveness of mpox vaccination. If optimal supplies of mpox vaccines can be secured, a low threshold approach at vaccination site could enable MSM with different levels of behavioral risks to become protected.