Vaccine Effectiveness of JYNNEOS against Mpox Disease in the United States

Effect of JYNNEOS vaccination on mpox clinical progression: a case-control study

BACKGROUND

The JYNNEOS modified vaccinia virus Ankara vaccine is effective in preventing clade IIb mpox disease. However, vaccine effects on mpox severity are poorly understood. We aimed to assess associations between reported clinical characteristics and vaccination status among individuals with laboratory-confirmed mpox.

METHODS

We conducted a case-control study using data collected from public health surveillance interviews of people with mpox in California. Eligible participants for primary analyses were men who were cisgender and participated in telephone interviews with complete responses recorded about anatomical sites where they had lesions. We estimated JYNNEOS vaccine effectiveness against progression to disease involving disseminated lesions via the adjusted odds ratio of vaccination, comparing participants who reported lesions disseminated across multiple anatomical regions (cases) with participants who reported lesions contained to a single anatomical region (controls). We used the same case-control framework to estimate vaccine effectiveness against progression to hospitalisation and prodromal symptoms.

FINDINGS

Men who were cisgender represented 5763 (94·3%) of 6112 people reported to have laboratory-confrimed mpox in California from May 12, 2022, to Dec 31, 2023, among whom, 4609 (79·9%) met eligibility criteria and were included in primary analyses. Of 4609 participants, 1566 (34·0%) were classified as controls and 3043 (66·0%) were classified as cases. Among 3043 cases, 114 (3·7%) received pre-exposure vaccination and 214 (7·0%) received post-exposure vaccination only. Among 1566 controls, 285 (18·2%) received pre-exposure vaccination and 146 (9·3%) received post-exposure vaccination only. For pre-exposure vaccination, vaccine effectiveness against progression was 58·8% (95% CI 50·3-65·9); for post-exposure vaccination, vaccine effectiveness against progression was 15·9% (3·3-26·8). Pre-exposure vaccine effectiveness against progression was 66·6% (56·8-74·2) among people negative for HIV and 44·8% (27·5-58·0) for those with HIV. Pre-exposure vaccination was also associated with protection against progression to severe illness necessitating hospitalisation (85·4% [95% CI 54·3-95·3]), and with reduced odds for fever, chills, and lymphadenopathy.

INTERPRETATION

Among men who were cisgender with mpox, pre-exposure vaccination with JYNNEOS was associated with less severe illness. Awareness of an attenuated disease phenotype involving localised lesions without accompanying prodromal symptoms is needed to ensure accurate diagnosis of mpox in previously vaccinated individuals.

FUNDING

The California Department of Public Health and the US National Institutes of Health.

Mpox multiprotein virus-like nanoparticle vaccine induces neutralizing and protective antibodies in mice and non-human primates

The upsurge of mpox in Africa and the recent global outbreak have stimulated the development of new vaccines and therapeutics. We describe the construction of virus-like particle (VLP) vaccines in which modified M1, A35 and B6 proteins from monkeypox virus (MPXV) clade Ia are conjugated individually or together to a scaffold that accommodates up to 60 ligands using the SpyTag/SpyCatcher nanoparticle system. Immunisation of female mice with VLPs induces higher anti-MPXV and anti-vaccinia virus (VACV) neutralizing antibodies than their soluble protein (SP) counterparts or modified VACV Ankara (MVA). Vaccination with individual single protein VLPs provides partial protection against lethal respiratory infections with VACV or MPXV clade IIa, whereas combinations or a chimeric VLP with all three antigens provide complete protection that is superior to SPs. Additionally, the VLP vaccine reduces the replication and spread of the virus at intranasal and intrarectal sites of inoculation. VLPs induce higher neutralizing activity than the Jynneos vaccine in rhesus macaques, and the VLP-induced antiserum provides better protection against MPXV and VACV than the Jynneos-induced antiserum when passively transferred to female mice. These data demonstrate that an mpox VLP vaccine derived from three MPXV clade Ia proteins protects against clade IIa MPXV and VACV, indicating cross-reactivity for orthopoxviruses.

Mpox vaccination coverage among Australian gay and bisexual men and non-binary people: Results of behavioural surveillance in early 2024

BACKGROUND

We examined characteristics associated with mpox vaccine uptake among gay, bisexual, queer and other men who have sex with men and non-binary people (GBQ+ people), the primary target group for Australian vaccination programs following the mid-2022 outbreak.

METHODS

Vaccine uptake was assessed using cross-sectional surveys of GBQ+ people from three Australian jurisdictions in 2024: Australian Capital Territory, New South Wales, and Victoria. Sexually active, mpox-undiagnosed participants were included. Multivariable logistic regression examined: (1) no vaccination vs. partial/full vaccination, and (2) partial vs. full vaccination.

RESULTS

Among 4252 participants, 46.2 % were unvaccinated, 12.3 % had received one vaccine dose, and 41.5 % had received two doses. Any vaccination was associated with: being >30 years old, being university-educated, being in a relationship, greater GBQ+ social engagement, being a PrEP user or person living with HIV vs. an HIV-negative non-PrEP-user, testing for HIV in the last year vs. >12 months ago, being diagnosed with chlamydia ≤12 months ago, having 2-10 recent sexual partners or > 10 partners vs. one recent partner, and meeting sex partners at sex venues and overseas. No vaccination was associated with: being bisexual vs. gay, being born in Asia or Latin America vs. Australia, and living in outer metropolitan or regional/remote areas vs. inner metropolitan areas. Compared to partial vaccination, full vaccination was associated with: being >30 years old, being a transgender vs. cisgender man, being university educated, and having >10 recent sexual partners vs. one.

CONCLUSIONS

Socially and clinically engaged gay men were more likely to be vaccinated against mpox. Younger participants, bisexual participants, those born in Asia and Latin America, and those living outside inner metropolitan areas were less likely to be vaccinated. We recommend targeted messaging and outreach to increase vaccination among people who attend sexual health services less frequently and those less socially engaged with QBQ+ people.

Poxvirus structural biology for application to vaccine design

The upsurge of mpox (formerly known as monkeypox) in Africa and its global spread highlight the need for improved vaccines. The development of new recombinant vaccines, including mRNA and protein nanoparticles, depends on understanding the biology of poxviruses and selecting the most protective immunogens. Animal studies demonstrate that vaccines need to target the antigens of both infectious forms - the mature virion and the enveloped virion - which display surface proteins responsible for cell entry and cell-to-cell spread, respectively. Although some of these proteins have been shown to induce protective antibodies, others including most of those that are essential for membrane fusion remain to be tested. We review the structures of orthopoxvirus surface proteins as a guide to the selection of optimal antigens for recombinant vaccines.

Transmission dynamics of the 2022 mpox epidemic in New York City

The 2022 global mpox epidemic was caused by transmission of MPXV clade IIb, lineage B.1 through sexual contact networks, with New York City (NYC) experiencing the first and largest outbreak in the United States. By performing phylogeographic analysis of MPXV genomes sampled from 757 individuals in NYC between April 2022 and April 2023, and 3,287 MPXV genomes sampled around the world, we identify over 200 introductions of MPXV into NYC with at least 84 leading to onward transmission. These infections primarily occurred among men who have sex with men, transgender women and nonbinary individuals. Through a comparative analysis with HIV in NYC, we find that both MPXV and HIV genomic cluster sizes are best fit by scale-free distributions, and that people in MPXV clusters are more likely to have previously received an HIV diagnosis and be a member of a recently growing HIV transmission cluster. We model MPXV transmission through sexual contact networks and show that highly connected individuals would be disproportionately infected at the start of an epidemic, which would likely result in the exhaustion of the most densely connected parts of the network, and, therefore, explain the rapid expansion and decline of the NYC outbreak. By coupling the genomic epidemiology of MPXV and HIV with epidemic modeling, we demonstrate that the transmission dynamics of MPXV in NYC can be understood by general principles of sexually transmitted pathogens.

Harnessing Nanohybridized Niclosamide for Precision Mpox Therapeutics

Niclosamide, initially developed as an anthelmintic, has recently emerged as a potential antiviral, showing efficacy against diverse viral threats, including Mpox. As the global health landscape faces recurrent Mpox outbreaks, repurposing niclosamide through advanced material strategies offers promising therapeutic avenues. This article explores the antiviral mechanisms of niclosamide, focusing on how innovative nano-hybrid formulations enhance its bioavailability and pharmacological performance. By leveraging nanohybridization, niclosamide's limitations-such as poor solubility and bioavailability-are addressed, enabling targeted delivery and sustained release. Early preclinical studies reveal that niclosamide disrupts Mpox replication and entry processes, suggesting its utility as a therapeutic option against poxvirus infections. Looking forward, further in vitro, animal models, and clinical investigations are essential to optimize its application and dosing for Mpox. With continued development in advanced materials, nanohybrid niclosamide could become a critical tool in managing Mpox and related viral threats, offering an accessible, cost-effective option for outbreak preparedness.

Effectiveness and Safety of Respiratory Syncytial Virus Vaccine for US Adults Aged 60 Years or Older

Importance

Respiratory syncytial virus (RSV) is associated with hospitalization and death among older adults. Characterizing the safety and effectiveness of recently introduced vaccines against RSV is critical.

Objective

To assess the safety and effectiveness of vaccines against RSV and the major adverse events among patients aged 60 years or older during the 2023-2024 RSV season.

Design, Setting, and Participants

In this study using a data platform containing electronic health records for more than 270 million patients across the US, a test-negative case-control design was used to estimate vaccine effectiveness (VE), and a self-controlled case series of vaccine recipients was included to estimate vaccine-associated adverse events. Records from participants aged 60 years or older with acute respiratory infection (ARI) and testing for RSV between October 1, 2023, and April 30, 2024, were included in the VE study. For vaccine safety analysis, all participants aged 60 years or older who received the RSV vaccine from July 1, 2023, to June 30, 2024 were included. Data were analyzed from August 2024 to March 2025.

Main Outcomes and Measures

Cases were those patients who tested positive for RSV, and controls were those who tested negative for RSV. Patients were classified as vaccinated if the vaccine was received at least 14 days before testing. VE against RSV-associated ARI diagnosis, emergency department or urgent care visits, or hospitalizations was estimated using (1 - odds ratio) × 100%. Excess risks of immune thrombocytopenic purpura and Guillain-Barré syndrome diagnosis for 6 weeks after vaccine administration were calculated.

Results

Of 787 822 patients tested for RSV, 53 963 were positive (733 859 were controls); 1318 cases (2.4%) and 66 928 controls (9.1%) were vaccinated. Overall, VE was 75.1% (95% CI, 73.6%-76.4%) against ARI and was similar for age groups of 60 to 74 years and 75 years or older and against urgent care visits or hospitalizations. Immunocompromised patients had a VE from 67.0% (95% CI, 62.6%-70.9%) for patients aged 60 to 74 years to 73.1% (95% CI, 69.9%-76.0%) for those aged 75 years or older, and the lowest VE (ie, from 29.4% [95% CI, 3.5%-48.4%] for patients aged 60-74 years to 44.4% [95% CI, 1.0%-68.8%] for those aged ≥75 years) was for a subgroup of patients who received stem cell transplants. Among 4 746 518 vaccine recipients, no excess risk of immune thrombocytopenic purpura diagnosis was detected. An excess of 5.2 cases (RSVPreF3+AS01) or 18.2 cases (RSVPreF) of Guillain-Barré syndrome were diagnosed per 1 000 000 doses of RSV vaccine administered.

Conclusions and Relevance

VE for the RSV protein subunit vaccine in this case-control study was similar to the VE in clinical trials. The VE for immunocompromised patients was mildly (overall) to moderately (for stem cell transplant recipients) diminished. Risk of immune thrombocytopenic purpura after vaccination was not elevated, but the risk of Guilain-Barré syndrome was statistically significantly elevated in patients who received the RSVPreF vaccine but not in those who received RSVPreF+AS01 vaccine, although the risk was small. These observations should inform clinicians' choices and patient instructions.

The impact of orthopoxvirus vaccination and Mpox infection on cross-protective immunity: a multicohort observational study

BACKGROUND

Cross-reactive immune memory responses to orthopoxviruses in humans remain poorly characterised despite their relevance for vaccine design and outbreak control. We aimed to assess the magnitude, specificity, and durability of cross-reactive immune responses elicited by smallpox vaccines and mpox virus infection.

METHODS

We did a multicohort observational study involving participants from the USA, Brazil, and Portugal across four groups: Dryvax (first-generation smallpox vaccine) recipients vaccinated 40-80 years ago, JYNNEOS (third-generation smallpox vaccine) recipients vaccinated within the past year, a cohort receiving both vaccines, and patients infected with clade IIb mpox. Samples were analysed for systemic and mucosal humoral responses, neutralising antibody titres, viral antigen structural analysis, and T-cell cross-reactivity to vaccina virus, cowpox virus, and mpox virus. Statistical analyses included correlation assessments and comparisons across cohorts to determine the magnitude, longevity, and breadth of immune responses.

FINDINGS

Between July 7, 2022, and Aug 3, 2023, 262 participants were recruited, resulting in analysis of 378 samples. Both first-generation and third-generation smallpox vaccines elicited vaccinia virus-reactive and mpox virus-reactive antibodies, with the strongest responses targeting the less conserved extracellular virion antigens B5 and A33. Despite high concentrations of anti-mpox virus antibodies in the plasma, cross-neutralisation activity correlated with viral antigenic distance. Higher neutralisation was observed for cowpox virus than for mpox virus, which has lower antigenic conservation with vaccina virus. Complement-mediated neutralisation enhanced mpox virus neutralisation, overcoming the limitations of antigenic distance. Dryvax recipients sustained vaccina virus neutralisation titres for over 80 years, whereas cross-reactive responses did not show this durability. JYNNEOS-induced responses waned within a year. T-cell cross-reactivity was long-lasting, detected up to 70 years after vaccination. Booster vaccinations augmented the magnitude, breadth, and longevity of cross-neutralising responses.

INTERPRETATION

Our findings highlight the potential combined role of antibody effector functions and T-cell memory in cross-protection against orthopoxviruses. Complement-mediated neutralisation enhances cross-protection, overcoming antigenic distance. These Fc-mediated functions, along with T-cell responses, contribute to effective and long-lasting immunity conferred by smallpox vaccines against other orthopoxviruses.

FUNDING

Yale University and Stavros Niarchos Foundation Institute for Global Infectious Disease.

Recent Advances in Mpox Epidemic: Global Features and Vaccine Prevention Research

Monkeypox (mpox) is a zoonotic disease (zoonose) caused by the monkeypox virus (MPXV). MPXV, a member of the Orthopoxviridae family, is categorized into two clades, Central Africa (I) and West Africa (II), each of which is further subdivided into subclades a and b. Clade I generally causes more serious illness and higher mortality rates, while Clade II results in milder illness. Historically, mpox epidemics were localized to specific regions and countries in Africa. Since 2022, the mpox epidemic, fueled by MPXV Clade IIb, has swiftly spread across various nations and regions, jeopardizing public health and safety. However, starting in 2024, Clade Ib gradually replaced Clade IIb. The notable genetic variation in Clade Ib may provide MPXV with new opportunities to evade the immune system and adapt to hosts. According to the World Health Organization (WHO), from 1 January 2022, to 24 November 2024, there were 117,663 confirmed cases and 2 probable cases, resulting in 263 deaths across 127 Member States in all six WHO regions. As of 9 January 2025, 12 countries outside Africa have reported imported MPXV Clade Ib cases, with secondary cases emerging in the United Kingdom, Germany, and China. Due to the incomplete development of a vaccine specifically for MPXV, the smallpox vaccine remains in use for preventing mpox or for emergency vaccination post-exposure. Therefore, the persistent spread of mpox is still a major concern, requiring greater awareness and vaccination efforts in populations at high risk. This paper aims to summarize the etiological characteristics, epidemic situation, and vaccine prevention efforts for mpox, offering a reference for managing this serious epidemic and ensuring effective scientific prevention and control.

Recurrent Mpox: divergent virulent clades and the urgent need for strategic measures including novel vaccine development to sustain global health security

In August 2024, the Africa CDC and WHO declared Mpox a Public Health Emergency of Continental Security and a Public Health Emergency of International Concern, respectively, following a devastating global outbreak driven by newly emerged virulent clades I (Ia, IIb) and II (IIa, IIb) of the Mpox virus. These new clades are genetically and phylogenetically distinct from previously known strains, with the re-emerging variants originating from the Democratic Republic of the Congo (DRC) and rapidly spreading to neighbouring regions and across the globe. The ongoing epidemic is characterized by alarming morbidity and mortality, and the newly identified clades are linked to significant changes in the epidemiology of the disease, resulting in worse clinical outcomes. Sexual transmission has emerged as a key factor in sustaining the spread of the virus, particularly among sexually active young adults, facilitating the virus's spread beyond Africa. To combat the growing threat, there is an urgent need for the development of a polyvalent vaccine that incorporates the diverse circulating clades as part of other mitigation measures.. Widespread vaccination with such a vaccine could help achieve herd immunity and complement other infection prevention and control strategies to effectively mitigate the impact of this global health crisis.

Generalizability of kidney transplant data in electronic health records - The Epic Cosmos database vs the Scientific Registry of Transplant Recipients

Developing real-world evidence from electronic health records (EHR) is vital to advancing kidney transplantation (KT). We assessed the feasibility of studying KT using the Epic Cosmos aggregated EHR data set, which includes 274 million unique individuals cared for in 238 US health systems, by comparing it with the Scientific Registry of Transplant Recipients (SRTR). We identified 69 418 KT recipients who underwent transplants between January 2014 and December 2022 in Cosmos (39.4% of all US KT transplants during this period). The demographics and clinical characteristics of recipients captured in Cosmos were consistent with the overall SRTR cohort. Survival estimates were generally comparable, although there were some differences in long-term survival. At 7 years posttransplant, patient survival was 80.4% in Cosmos and 77.8% in SRTR. Multivariable Cox regression showed consistent associations between clinical factors and mortality in both cohorts, with minor discrepancies in the associations between death and both age and race. In summary, Cosmos provides a reliable platform for KT research, allowing EHR-level clinical granularity not available with either the transplant registry or health care claims. Consequently, Cosmos will enable novel analyses to improve our understanding of KT management on a national scale.

Short-term evolution of Mpox-specific IgG and neutralizing antibodies among individuals undergoing MVA-BN vaccination

OBJECTIVES

The data on immune responses of individuals undergoing modified vaccinia Ankara-Bavarian Nordic (MVA-BN) vaccination are scarce. We aimed to compare Mpox virus-specific antibody and neutralizing antibody responses among people with and those without HIV receiving MVA-BN vaccines.

METHODS

This prospective study enrolled participants undergoing two-dose MVA-BN vaccination to investigate seroresponses after vaccination. Blood samples were collected before and after each dose of vaccination for determinations of anti-A29 and anti-H3 IgG. Neutralization tests were conducted for samples tested positive for both anti-A29 and anti-H3 IgG.

RESULTS

Overall, 441 participants undergoing two-dose MVA-BN vaccination were enrolled. Seroconversion for anti-A29 and anti-H3 IgG, respectively, after the second dose of vaccination was 18.2% and 61.2%, 10.9% and 65.0%, and 51.6% and 90.6% among people with HIV, people without HIV, and those who had had smallpox vaccination previously, respectively. About 20% of the participants with seroconversion lost seroresponses after a 7-month period of observation. None of the serum samples from vaccinated participants demonstrated neutralizing ability.

CONCLUSIONS

Participants with previous smallpox vaccination had higher and more sustained antibody responses after receiving two doses of MVA-BN vaccines than those who had not undergone smallpox vaccination. More studies are warranted to assess the seroresponses to booster MVA-BN vaccination for vaccine nonresponders or those having lost seroresponses.

Is Southeast Asia and the Western Pacific ready for potential monkeypox virus outbreaks?

The new variant of the monkeypox virus (MPXV) clade Ib has recently spread to other African countries outside the Democratic Republic of the Congo (DRC), prompting the World Health Organisation to declare the outbreak as a public health emergency of international concern (PHEIC). This comes just two years after the initial PHEIC that was issued for the clade IIb outbreaks. Compared to the clade IIb outbreaks, clade Ib shows a demographic shift, including higher case fatality rates for younger individuals, indicating a possibility of additional transmission pathways through heterosexual and household contacts. Given that many countries in the Western Pacific (WPR) and the Southeast Asian region (SEAR) hold a disproportionate burden of endemic infectious diseases and have difficulties engaging key at-risk populations, an outbreak of the potentially more virulent clade Ib virus could have devastating impacts on the health care systems. Thus, strategy planning against the potential emergence of clade Ib MPXV in the regions is required, including surveillance systems for detection, modelling studies to perform risk assessments, implementation of non-pharmaceutical interventions, and vaccination, and regional collaboration to ensure equitable distribution of vaccinations.

Mpox Vaccine Communication Among Sexually Active Men Who Have Sex With Men

ABSTRACT

We assessed mpox vaccine communication and sexual behavior among US men who have sex with men during the 2022 mpox outbreak. Less than 40% of respondents asked a new male sex partner about their mpox vaccination status. Mpox vaccine communication was positively associated with condomless anal sex and group sex. Mpox vaccine communication is low but may inform mpox risk perception and sexual behaviors among men who have sex with men.

Impact of interventions on mpox transmission during the 2022 outbreak in Canada: a mathematical modeling study of three different cities

OBJECTIVES

The global mpox (clade II) outbreak of 2022 primarily affected gay, bisexual, and other men who have sex with men (GBM) and was met with swift community and public health responses. We aimed to estimate the relative impact of changes in sexual behaviors, contact tracing/isolation, and first-dose vaccination on transmission in Canadian cities.

METHODS

We estimated changes in sexual behaviors during the outbreak using 2022 data from the Engage Cohort Study, which recruited self-identified GBM in Montréal, Toronto, and Vancouver (n = 1,445). We developed a transmission dynamic model to estimate the fraction of new infections averted due to the three interventions in each city.

RESULTS

The empirical estimates of sexual behavior changes were imprecise: a 20% reduction (RR = 0.80; 95% credible interval [95% CrI]: 0.47-1.36) in the number of sexual partners in the past 6 months among those reporting ≤7 partners and a 33% (RR = 0.67; 95% CrI: 0.31-1.43) reduction among those with >7 partners. The three interventions combined averted 46%-58% of cases. Reductions in sexual partners and contact tracing/isolation prevented approximately 12% and 14% of cases, respectively. Vaccination's effect varied across cities due to the programs' timing and coverage, with 21%-39% mpox infections prevented.

CONCLUSIONS

Reduction in sexual activity, contact tracing/isolation, and vaccination all contributed to accelerating epidemic control. Early vaccination had the largest impact.

Monkeypox Virus: WHO's Second Public Health Emergency of International Concern Within 2 Years

An upsurge of monkeypox disease (mpox) cases with clade I virus in Central Africa led WHO to declare a Public Health Emergency of International Concern for a second time shortly after the worldwide clade II mpox epidemic in 2022/3 among homosexual men. In the Democratic Republic of Congo (DRC), the annual incidence of clade I mpox, transmitted mostly from animal sources to children, increased 20-fold between 1980 and 2007; 60,000 mpox cases occurred between 2010 and 2023. The incidence again doubled between 2023 and 2024, showing a case fatality rate of 3.3%. A new clade Ib virus was detected in 2024 in eastern DRC where mostly adults were infected by heterosexual contact. Ib was recently introduced and showed a mutation spectrum of human-to-human transmission. Asymptomatic mpox infections, the release of infectious virus before symptom onset in a subgroup of cases, and superspreaders complicate containment measures during the 2022 epidemic. Isolation of cases until two consecutive negative PCR tests was recommended but necessitates cheap and rapid diagnostic tests which are in development. Sexual behavioural changes during the 2022 epidemic have contributed more to the curbing of the epidemic than vaccination. The smallpox vaccine Dryvax protected children exposed to clade I mpox in DRC in the 1980s. The attenuated third-generation smallpox Modified Vaccinia Ankara (MVA) vaccines and derivatives showed robust protection against clade IIb mpox during the 2022/3 epidemic in various study formats. Vaccine efficacy exceeding 75% was reported after two doses. mRNA in lipid-nanoparticle encoding surface proteins from extracellular enveloped and intracellular mature virions of monkeypox virus (MPXV) induced humoral and cellular immune responses that protected macaques against mpox disease with clade I and II viruses better than MVA. Only mixtures of monoclonal antibodies protected mice from mpox. The antiviral tecovirimat showed no efficacy in two clinical trials against clade I and II mpox.

Mobile Mpox Vaccination in New York City Provided Flexible Community-Responsive Vaccine Access During the 2022 Global Mpox Emergency

Background

In May 2022, mpox (formerly monkeypox) began spreading globally through LGBTQ+ sexual networks. By August 2022, New York City (NYC) became the global epicenter of the mpox outbreak, with the highest number of cases reported in the United States. Here, we quantify the mpox vaccination effort, focusing on flexible and community-responsive mobile vaccination.

Methods

We describe an on-site mpox vaccination strategy at commercial sex venues, nightlife venues, and pride and health centers, during August 1-November 15, 2022. Data were collected on doses, demographics, and event size to determine and evaluate vaccine uptake.

Results

The on-site vaccination strategy resulted in 3358 JYNNEOS doses administered at 363 events at 58 locations, including 22 events at 2 commercial sex venues. Commercial sex venues in New York City closed at the height of the mpox epidemic. We show high uptake of the JYNNEOS vaccine at commercial sex venues, with as many as 60% of attendees of 1 event receiving a JYNNEOS vaccine dose on site. This was possible after New York City health agencies responded to community demand for second doses. Messaging about the importance and availability of vaccination at these parties was community-led. JYNNEOS vaccination via mobile clinics demonstrated less racial and geographic disparity compared with nonmobile vaccinations. We show no increase in mpox cases as commercial sex venues reopened with vaccination on site.

Conclusions

These results demonstrate the success of a community-led rapid response to an emergent mpox outbreak, including at places where people meet for sex.

Safety and effectiveness of MVA-BN vaccination against mpox in at-risk individuals in Germany (SEMVAc and TEMVAc): a combined prospective and retrospective cohort study

BACKGROUND

More than 115 000 cases of mpox have been confirmed since the onset of a global outbreak in 2022. In addition to global transmission of clade II monkeypox virus (MPXV), the recent spread of clade I has caused a Public Health Emergency of International Concern. The third-generation smallpox vaccine modified vaccinia Ankara-Bavarian Nordic (MVA-BN) was recommended for at-risk populations in 2022, despite a scarcity of data on safety and effectiveness against mpox.

METHODS

We did a prospective, multicentre, observational study, enrolling men who have sex with men and transgender people aged 18 years or older with changing sexual partners in Germany (Safety and Effectiveness of MVA-BN Vaccination Against MPXV Infection [SEMVAc]) between July 7, 2022, and Dec 31, 2023, evaluating safety and reactogenicity of one and two doses of subcutaneous MVA-BN. Vaccine effectiveness was estimated using risk ratios from the Kaplan-Meier estimator in an emulated retrospective target trial (Emulated Target Trial for Effectiveness of MVA-BN Vaccination Against mpox Infection in At-risk Individuals [TEMVAc]) from 3027 vaccinated individuals matched (1:1) to 3027 unvaccinated controls. SEMVAc and TEMVAc were registered in the HMA-EMA Catalogue, EUPAS50093, and the German Clinical Trials Register, DRKS00029638, and are complete.

FINDINGS

6459 individuals were prospectively enrolled in SEMVAc. Adverse reactions were infrequent (first dose: 0·35% [95% CI 0·20-0·60] and second dose: 0·14% [0·06-0·33]). Local reactions were more frequent after the first dose (70·2% [95% CI 68·5-71·8]) compared with the second dose (56·8% [54·6-59]), as were systemic reactions (first dose, 22·3% [95% CI 20·9-23·9]; second dose, 17·6% [15·9-19·4]). In TEMVAc, 16 mpox cases were reported in vaccinated individuals versus 32 cases in matched unvaccinated individuals (median follow-up 55 days [IQR 23-89]). Effectiveness by 14 days or later after one dose was 57·8% (95% CI 11·8 to 83·0) overall, 84·1% (42·0 to 100) in people without HIV, but 34·9% (-72·8 to 79·0) in people living with HIV. Breakthrough infections were associated with reduced symptoms, compared with infections in unvaccinated individuals.

INTERPRETATION

MVA-BN vaccination was safe and well tolerated. One dose of MVA-BN offered protection against mpox but effectiveness was reduced in people living with HIV. Although randomised controlled trials remain the preferred approach for assessing vaccine efficacy, combining prospective and retrospective study designs can be valuable during dynamic public health emergencies.

FUNDING

European Medicines Agency.

TRANSLATION

For the German translation of the abstract see Supplementary Materials section.

Humoral Immunity Against Orthopoxvirus in Vaccinated and Unvaccinated Individuals during 2022 Mpox Outbreak

Little is known about serological responses to MVA-BN (JYNNEOS) against mpox in elderly individuals with or without HIV. In this study, MVA-BN induced sustained IgG levels regardless of HIV status even up to one year. Birth before 1973 correlated with higher IgG. MVA-BN unvaccinated individuals with HIV had lower IgG than vaccinated.

An overview of the progress made in research into the Mpox virus

Mpox is a zoonotic illness caused by the Mpox virus (MPXV), a member of the Orthopoxvirus family. Although a few cases have been reported outside Africa, it was originally regarded as an endemic disease limited to African countries. However, the Mpox outbreak of 2022 was remarkable in that the infection spread to more than 123 countries worldwide, causing thousands of infections and deaths. The ongoing Mpox outbreak has been declared as a public health emergency of international concern by the World Health Organization. For a better management and control of the epidemic, this review summarizes the research advances and important scientific findings on MPXV by reviewing the current literature on epidemiology, clinical characteristics, diagnostic methods, prevention and treatment measures, and animal models of MPXV. This review provides useful information to raise awareness about the transmission, symptoms, and protective measures of MPXV, serving as a theoretical guide for relevant institutions to control MPXV.

A review of epidemiology, diagnosis, and management of Mpox: The role of One Health

Human monkeypox (Mpox) is an emerging zoonotic disease. Its clinical features are similar to but less severe than those of smallpox. The etiology of this disease is the monkeypox virus. This virus is a double-stranded DNA virus that is classified into the genus Orthopoxvirus and the family Poxviridae. Human monkeypox was first identified in 1970 and mainly occurred in Central and Western Africa. In 2022, outbreaks of Mpox virus infection occurred in several non-endemic countries and caused a potential threat to humans. It is urgent to take immediate action to control and prevent the outbreak of the Mpox virus infection. This paper summarizes the current status of Mpox and generated strategies for managing the Mpox epidemic. Although progress in the diagnostic methods and treatment of Mpox produces better knowledge, we argue that the sensitive surveillance for animal and human Mpox virus infection and evidence-based response and management of Mpox outbreaks is critical. This study highlights the need for further research on preventive and control strategies for Mpox disease approached through the One Health concept.

Epidemiology and Clinical Features of Mpox in Jakarta, Indonesia, August 2022-December 2023

BACKGROUND/OBJECTIVE

This study explores the epidemiology and clinical features of re-emerging mpox in Jakarta, Indonesia.

METHODS

This study used a retrospective study design to describe the epidemiological data, clinical features, and mortality of mpox patients from August 2022 to December 2023. In addition, this study also aims to identify the differences in both the epidemiology and clinical features of mpox in people living with HIV (PLHIV) and in non-HIV patients (non-PLHIV).

RESULTS

Our study shows that, as of the end of December 2023, 59 mpox cases were treated in Jakarta. All of the mpox cases in Jakarta were diagnosed in males, mainly found in MSM (91.5%), and PLHIV (78%). Most patients would manifest with fever, rash, and skin lesions. Syphilis was found as a concomitant infection in this group (22/59, 37.2%). Severe manifestations were found among PLHIV without antiretroviral therapy (ART).

CONCLUSIONS

Mpox cases in Jakarta were all found in males and most of them were PLHIV. There are various manifestations of mpox; however, since immunosuppressed patients could present differently, a strong surveillance and vaccine notification system, cautious management, and spreading vaccination awareness are needed to prevent and treat mpox.

Risk factors associated with human Mpox infection: a systematic review and meta-analysis

BACKGROUND

Mpox emerged as a significant global public health concern during the 2022-2023 outbreak, impacting populations in both endemic and non-endemic countries. This study reviews and synthesises evidence on the risk factors associated with human Mpox transmission across these regions.

METHODS

A systematic search of peer-reviewed original studies was conducted across Scopus, Embase, Web of Science and PubMed databases, covering publications up to 31 March 2024. The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Two authors independently screened the articles by title, abstract and full text. The Newcastle-Ottawa Scale used to assess the risk of bias for included articles. Fixed- or random-effects meta-analysis was conducted when at least two studies reported ORs or relative risks, with 95% CIs. Heterogeneity was assessed using the [Formula: see text] statistic. This study was registered on PROSPERO (ID: CRD42023459895).

RESULTS

The systematic review identified 947 articles through database searches, of which 31 met our inclusion criteria. The meta-analysis revealed significant risk factors associated with Mpox infection. Interaction with infected animals (OR=5.61, 95% CI 2.83, 11.13), HIV infection (OR=4.46, 95% CI 3.27, 6.08), other sexually transmitted infections (OR=1.76, 95% CI 1.42, 2.19), unprotected sexual activities (OR=1.53, 95% CI 1.13, 2.07), contact with an infected person (OR=2.39, 95% CI 1.87, 3.05), identification as men who have sex with men (OR=2.18, 95% CI 1.88, 2.51) and having multiple sexual partners (OR=1.61, 95% CI 1.24, 2.09) were associated with increased Mpox infection risk. Conversely, smallpox vaccination was associated with a significantly reduced risk of Mpox infection (OR=0.24, 95% CI 0.11, 0.55).

CONCLUSION

Identification of risk factors associated with Mpox provides insights for strategic public health planning, enabling targeted interventions for high-risk groups and optimising resource allocation to strengthen Mpox control efforts.

"Mpox in MSM: Tackling stigma, minimizing risk factors, exploring pathogenesis, and treatment approaches"

Mpox is a zoonotic disease caused by the monkeypox virus (MPV), primarily found in Central and West African countries. The typical presentation of the disease before the 2022 mpox outbreak includes a febrile prodrome 5-13 days post-exposure, accompanied by lymphadenopathy, malaise, headache, and muscle aches. Unexpectedly, during the 2022 outbreak, several cases of atypical presentations of the disease were reported, such as the absence of prodromal symptoms and the presence of genital skin lesions suggestive of sexual transmission. As per the World Health Organization (WHO), as of March 20, 2024, 94,707 cases of mpox were reported worldwide, resulting in 181 deaths (22 in African endemic regions and 159 in non-endemic countries). The United States Centers for Disease Control and Prevention (CDC) reports a total of 32,063 cases (33.85% of total cases globally), with 58 deaths (32.04% of global deaths) due to mpox. Person-to-person transmission of mpox can occur through respiratory droplets and sustained close contact. However, during the 2022 outbreak of mpox, a high incidence of anal and perianal lesions among MSMs indicated sexual transmission of MPV as a major route of transmission. Since MSMs are disproportionately at risk for HIV transmission. In this review, we discusses the risk factors, transmission patterns, pathogenesis, vaccine, and treatment options for mpox among MSM and people living with HIV (PLWH). Furthermore, we provide a brief perspective on the evolution of the MPV in immunocompromised people like PLWH.

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.

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.

Methodological challenges using routine clinical care data for real-world evidence: a rapid review utilizing a systematic literature search and focus group discussion

BACKGROUND

The integration of real-world evidence (RWE) from real-world data (RWD) in clinical research is crucial for bridging the gap between clinical trial results and real-world outcomes. Analyzing routinely collected data to generate clinical evidence faces methodological concerns like confounding and bias, similar to prospectively documented observational studies. This study focuses on additional limitations frequently reported in the literature, providing an overview of the challenges and biases inherent to analyzing routine clinical care data, including health claims data (hereafter: routine data).

METHODS

We conducted a literature search on routine data studies in four high-impact journals based on the Journal Citation Reports (JCR) category "Medicine, General & Internal" as of 2022 and three oncology journals, covering articles published from January 2018 to October 2023. Articles were screened and categorized into three scenarios based on their potential to provide meaningful RWE: (1) Burden of Disease, (2) Safety and Risk Group Analysis, and (3) Treatment Comparison. Limitations of this type of data cited in the discussion sections were extracted and classified according to different bias types: main bias categories in non-randomized studies (information bias, reporting bias, selection bias, confounding) and additional routine data-specific challenges (i.e., operationalization, coding, follow-up, missing data, validation, and data quality). These classifications were then ranked by relevance in a focus group meeting of methodological experts. The search was pre-specified and registered in PROSPERO (CRD42023477616).

RESULTS

In October 2023, 227 articles were identified, 69 were assessed for eligibility, and 39 were included in the review: 11 on the burden of disease, 17 on safety and risk group analysis, and 11 on treatment comparison. Besides typical biases in observational studies, we identified additional challenges specific to RWE frequently mentioned in the discussion sections. The focus group had varied opinions on the limitations of Safety and Risk Group Analysis and Treatment Comparison but agreed on the essential limitations for the Burden of Disease category.

CONCLUSION

This review provides a comprehensive overview of potential limitations and biases in analyzing routine data reported in recent high-impact journals. We highlighted key challenges that have high potential to impact analysis results, emphasizing the need for thorough consideration and discussion for meaningful inferences.

Urogenital Manifestations in Mpox (Monkeypox) Infection: A Comprehensive Review of Epidemiology, Pathogenesis, and Therapeutic Approaches

Monkeypox (mpox), caused by mpox virus (MPXV) infection, reemerged in 2022 and still raises concerns globally. Abundant clinical data indicate that mpox is a sexually transmitted infection and that the urogenital system is the most frequently involved system in mpox, which deserves more attention. Penile lesions are the most common presentation, followed by urethritis. Acute urine retention and acute kidney injury are relatively rare but also highly crucial. Currently, the majority of the urogenital lesions are considered complications secondary to MPXV infection and the common immunosuppression in mpox patients. However, such viewpoints should be treated carefully due to the lack of understanding of the basic mpox pathology. Here, we briefly and comprehensively review the current evidence concerning urogenital lesions caused by mpox, including epidemiology, clinical features, pathogenesis, and therapeutic approaches to provide a preliminary reference for clinicians in future clinical practice.

Impact of Point-of-Care Testing on Diagnosis, Treatment, and Surveillance of Vaccine-Preventable Viral Infections

With the advent of a variety of vaccines against viral infections, there are multiple viruses that can be prevented via vaccination. However, breakthrough infections or uncovered strains can still cause vaccine-preventable viral infections (VPVIs). Therefore, timely diagnosis, treatment, and surveillance of these viruses is critical to patient care and public health. Point-of-care (POC) viral diagnostics tools have brought significant improvements in the detection and management of VPVIs. These cutting-edge technologies enable prompt and accurate results, enhancing patient care by facilitating timely treatment decisions. This review delves into the advancements in POC testing, including antigen/antibody detection and molecular assays, while focusing on their impact on the diagnosis, treatment, and surveillance of VPVIs such as mpox, viral hepatitis, influenza, flaviviruses (dengue, Zika, and yellow fever virus), and COVID-19. The role of POC tests in monitoring viral infection is crucial for tracking disease progression and managing outbreaks. Furthermore, the application of POC diagnostics has shown to be vital for public health strategies. In this review, we also highlight emerging POC technologies such as CRISPR-based diagnostics and smartphone-integrated POC devices, which have proven particularly beneficial in resource-limited settings. We underscore the importance of continued research to optimize these diagnostic tools for wider global use for mpox, viral hepatitis, influenza, dengue, and COVID-19, while also addressing current challenges related to their sensitivity, specificity, availability, efficiency, and more.

Assessing healthcare workers’ knowledge and confidence in the diagnosis, management and prevention of Monkeypox

BACKGROUND

Monkeypox (Mpox), is a disease of global public health concern, as it does not affect only countries in western and central Africa.

AIM

To assess Burundi healthcare workers (HCWs)s’ level of knowledge and confidence in the diagnosis and management of Mpox.

METHODS

We conducted a cross-sectional study via an online survey designed mainly from the World Health Organization course distributed among Burundi HCWs from June-July 2023. The questionnaire comprises 8 socioprofessional-related questions, 22 questions about Mpox disease knowledge, and 3 questions to assess confidence in Mpox diagnosis and management. The data were analyzed via SPSS software version 25.0. A P value < 0.05 was considered to indicate statistical significance.

RESULTS

The study sample comprised 471 HCWs who were mainly medical doctors (63.9%) and nurses (30.1%). None of the 22 questions concerning Mpox knowledge had at least 50% correct responses. A very low number of HCWs (17.4%) knew that Mpox has a vaccine. The confidence level to diagnose (21.20%), treat (18.00%) or prevent (23.30%) Mpox was low among HCWs. The confidence level in the diagnosis of Mpox was associated with the HCWs’ age (P value = 0.009), sex (P value < 0.001), work experience (P value = 0.002), and residence (P value < 0.001). The confidence level to treat Mpox was significantly associated with the HCWs’ age (P value = 0.050), sex (P value < 0.001), education (P value = 0.033) and occupation (P value = 0.005). The confidence level to prevent Mpox was associated with the HCWs’ education (P value < 0.001), work experience (P value = 0.002), residence (P value < 0.001) and type of work institution (P value = 0.003).

CONCLUSION

This study revealed that HCWs have the lowest level of knowledge regarding Mpox and a lack of confidence in the ability to diagnose, treat or prevent it. There is an urgent need to organize continuing medical education programs on Mpox epidemiology and preparedness for Burundi HCWs. We encourage future researchers to assess potential hesitancy toward Mpox vaccination and its associated factors.

Concurrent outbreaks of mpox in Africa-an update

In this Review, we examine the concurrent outbreaks of mpox in Africa, focusing on clade 1a, the newly emerged clade 1b, and clade 2b lineage A, and how they differ from the 2022 global outbreak caused by clade 2b lineage B.1. Historically, clades 1a and 2a have caused sporadic, small outbreaks in central and west Africa, respectively, primarily through zoonotic transmission. Clade 2b first caused an outbreak in Nigeria in 2017, and later spread globally via sexual contact in 2022. In August, 2024, WHO declared a global health emergency due to the newly identified clade 1b outbreak in eastern Democratic Republic of the Congo. This outbreak has now expanded to several other countries and is spreading through direct and sexual contact in urban centres and refugee camps. Clades, route of exposure, infectious dose, and host immune response are the main factors influencing clinical presentation of mpox. For clades 1a and 2a, zoonotic transmission plays an important role, whereas for clades 1b and 2b, the spread occurs through sustained human-to-human transmission without zoonotic exposure. For both clades 1a and 2a, lesions have a generalised centrifugal distribution, whereas for clade 2b they are mainly localised to the anogenital area. For clade 1b, data are still emerging, but current cases show a mix of localised lesions and centrifugal distribution. The severity of the disease is higher for clade 1a (case fatality rate up to 12%) compared with other clades (case fatality rates 0-3·6%). Diagnostic challenges include false negative results for clade 1b with existing PCR assays and poor testing access in remote areas. Tecovirimat, the primary antiviral during the 2022 outbreak, has shown reduced effectiveness against clade 1a in preliminary study results, whereas its efficacy against other clades is still under investigation. The modified vaccinia Ankara-Bavarian Nordic vaccine has been shown to be up to 90% effective against clade 2b after two doses and is safe for children, although its effectiveness drops to 20% when used as post-exposure prophylaxis. Given the evolving nature of the monkeypox virus, ongoing research and strong public health responses are key to managing potential future outbreaks.

Long-Lasting Protection and Dose Optimization of MPXV Polyvalent Mpox mRNA Vaccines Against Lethal Vaccinia Virus Challenge in Mice

The outbreak of clade II monkeypox virus (MPXV) and the additional outbreak in Central Africa of clade I virus from 2023 have attracted worldwide attention. The development of a scalable and effective vaccine against the ongoing epidemic of mpox is urgently needed. We previously constructed two bivalent MPXV mRNA vaccines, LBA (B6R-A29L) and LAM (A35R-M1R), and a quadrivalent mRNA vaccine, LBAAM (B6R-A35R-A29L-M1R). These vaccines at a 20 µg dose could induce potential MPXV antigen-specific immune responses and provide protection against lethal VACV challenge. Compared with the individual bivalent mRNA vaccines, the two quadrivalent vaccines LBAAM and LBA& LAM displayed superior protective effects. To characterize these vaccines further, we monitored long-term immunity and protection as long as 28 weeks after initial immunization and optimized the immunization dosages to decrease the cost of production for future clinical use. Our results demonstrated that both the bivalent MPXV mRNA vaccine LAM (A35R-M1R) and the two tetravalent vaccines LBAAM and LBA& LAM could elicit long-lasting antigen-specific IgG antibodies as well as neutralizing antibodies against VACV and MPXV. They all provided complete protection against VACV challenge until 28 weeks post prime immunization. Moreover, the immunogenicity and protective efficacy of the two tetravalent vaccines (LBAAM and LBA& LAM) are dose dependent, and even the low-dose (1 µg) vaccine could provide sufficient protection against lethal VACV challenge. These results provide valuable clues for the further production of MPXV mRNA vaccines for use in humans.

Summary of the National Advisory Committee on Immunization (NACI) Statement-Updated guidance on Imvamune in the context of a routine immunization program

Background

Mpox is a viral illness related to smallpox. It can cause flu-like symptoms and a rash, and in severe cases, can lead to hospitalization or death. The Imvamune® vaccine offers protection against mpox. Consistent with global trends, mpox cases in Canada have been reported primarily among men who have sex with men (MSM), with sexual contact as the predominantly reported mode of transmission. While the incidence of mpox in Canada has significantly declined since the fall of 2022, mpox remains an important public health concern with the potential for future resurgence.

Methods

The National Advisory Committee on Immunization (NACI) reviewed available evidence on the clinical benefits and risks of Imvamune. This evidence included studies assessing the vaccine effectiveness estimates from real-world evidence, as well as pre- and post-market licensure safety data. NACI has also considered additional factors including ethics, equity, feasibility and acceptability. Guidance on the use of Imvamune in the context of international travel was developed in collaboration with the Canadian Committee to Advise on Tropical Medicine and Travel (CATMAT).

Results

NACI concluded that available evidence supported the vaccine's effectiveness and safety in preventing mpox infection.

Conclusion

Building on previous interim guidance from NACI recommending the use of Imvamune for pre-exposure vaccination in the context of ongoing mpox outbreaks, NACI now recommends that Imvamune be used in the context of a focused routine immunization program. Individuals at high risk of mpox, including MSM who meet high-risk criteria such as having more than one sexual partner, should receive two doses of Imvamune administered by subcutaneous injection at least 28 days apart.

The Rise of Mpox in a Post-Smallpox World

Reports of mpox are rising in Africa where the disease is endemic and in new countries where the disease has not been previously seen. The 2022 global outbreak of clade II mpox and an ongoing outbreak of the more lethal clade I mpox highlight the pandemic potential for monkeypox virus. Waning population immunity after the cessation of routine immunization for smallpox plays a key role in the changing epidemiologic patterns of mpox. Sustained human-to-human transmission of mpox is occurring widely in the context of insufficient population immunity, fueling genetic mutations that affect the accuracy of some diagnostic tests and that could lead to changing virulence. Additional research should address complex challenges for control of mpox, including improved diagnostics and medical countermeasures. The availability of vaccines should be expanded not only for outbreak response but also for broader routine use for persons in mpox-endemic countries.

Poxvirus Epidemiology

Illnesses caused by poxviruses have plagued humanity for millennia. The most notable are caused by viruses comprising the orthopoxvirus genus. Smallpox (caused by Variola virus) became the first eradicated disease in 1980. Devotion to smallpox eradication required significant orthopoxvirus research and discovery including vaccine and medical countermeasure development. Here we describe historical and current poxvirus epidemiology, with particular emphasis on orthopoxviruses including Monkeypox virus and Vaccinia virus.

Equivalence of freeze-dried and liquid-frozen formulations of MVA-BN as smallpox and mpox vaccine

Modified Vaccinia Ankara Bavarian Nordic (MVA-BN) as a smallpox and mpox vaccine has been approved in its liquid-frozen (LF) formulation in the US, Canada, and EU. A freeze-dried (FD) formulation may offer additional benefits, such as a longer shelf life and reduced dependence on cold chain storage and transport. In a phase 2 clinical trial, 651 vaccinia-naïve participants were vaccinated with two doses of MVA-BN LF or FD, 4 weeks apart. The objectives were to compare MVA-BN FD with LF in terms of vaccine-induced immune responses, safety, and reactogenicity. Non-inferiority of the immune response was assessed by the 95% CI of the geometric mean ratios. Both formulations induced robust vaccinia-specific humoral and cellular immune responses. At peak humoral responses (Week 6), geometric means of total antibody titers were 1096 (95% CI 1013, 1186) from the FD group and 877 (95% CI 804, 956) from the LF group, achieving the primary endpoint of non-inferiority of MVA-BN FD compared to MVA-BN LF. At peak cellular responses (Week 2), geometric means of T cell spot forming units were 449 (95% CI 341, 590) from the FD group and 316 (95% CI 234, 427) from the LF group. Both formulations of MVA-BN were well tolerated, with similar unsolicited AEs and solicited systemic reactions in both groups but slightly more local reactions in the FD group. No vaccine-related serious adverse events (SAEs) or vaccine-related AE of special interest were reported. The FD formulation of MVA-BN was shown to be equivalent to MVA-BN LF.

Mpox mRNA-1769 vaccine inhibits orthopoxvirus replication at intranasal, intrarectal, and cutaneous sites of inoculation

We previously reported that mice immunized twice with a lipid nanoparticle vaccine comprising four monkeypox viral mRNAs raised neutralizing antibodies and antigen-specific T cells and were protected against a lethal intranasal challenge with vaccinia virus (VACV). Here we demonstrated that the mRNA vaccine also protects mice against intranasal and intraperitoneal infections with monkeypox virus and bioluminescence imaging showed that vaccination greatly reduces or prevents VACV replication and spread from intranasal, rectal, and dermal inoculation sites. A single vaccination provided considerable protection that was enhanced by boosting for at least 4 months. Protection was related to the amount of mRNA inoculated, which correlated with neutralizing antibody levels. Furthermore, immunocompetent and immunodeficient mice lacking mature B and T cells that received serum from mRNA-immunized macaques before or after VACV challenge were protected. These findings provide insights into the mechanism and extent of mRNA vaccine-induced protection of orthopoxviruses and support clinical testing.

Recombinant chimeric horsepox virus (TNX-801) is attenuated relative to vaccinia virus strains in both in vitro and in vivo models

Recombinant chimeric horsepox virus (TNX-801) is a preclinical vaccine in development against mpox and smallpox. In this report, we investigated the potential phenotypic differences in in vitro and in vivo models between TNX-801 and older vaccinia virus (VACV)-based vaccine strains (VACV-Lis and VACV-NYCBH) used in the eradication of smallpox as well as VACV-WR, VACV-IHD, and MVA. TNX-801 displayed a small plaque phenotype (~1-2 mm) in BSC-40 and Vero-E6 cells. Multi-step replication kinetics in immortalized nonhuman primate cell lines, and human primary cells from dermal and respiratory tracts yielded >10- to 100-fold lower infectious titers than the VACV strains. In addition, the infectious particle-to-genome copy ratio data suggests that TNX-801 genome packaging is ~10- to 100-fold less efficient than the VACV strains and the potential mechanism of TNX-801 attenuation is at the packaging/egress stage. Lastly, the susceptibility to VACV and TNX-801 infection of three new immunocompromised murine models (C56BL/6 Ifnar-/-, C56BL/6 Ifngr-/-, and C56BL/6 Ifnar-/-/Ifngr-/-) was investigated. VACV strains were able to produce severe disease including decrease in body weight and temperature, as well as lethality in murine models via the intraperitoneal or intranasal routes. In contrast to VACV strains, TNX-801 was unable to produce any disease in murine models. These data demonstrate that TNX-801 is >10- to 1,000-fold more attenuated compared to older VACV-based smallpox vaccine strains in human primary cell lines and immunocompromised mice.

IMPORTANCE

Variola and monkeypox viruses are medically important pathogens that can cause fatal human disease. The two FDA-approved vaccines, ACAM-2000 and JYNNEOS, have important advantages and disadvantages. ACAM-2000 offers durable immunity; however, it has high adverse event rates. In contrast, JYNNEOS has a safer profile but requires two doses 4-weeks apart to achieve comparable immunity. Consequently, there is a need for vaccines offering durable immunity via single immunization with minimal adverse events. TNX-801 is a preclinical stage vaccine that can stimulate potent immunity via a single dose and provides protection against lethal mpox disease in the nonhuman primate model. Here, we show that TNX-801 is >10- to 1,000-fold attenuated in in vitro and in vivo models including human primary cells and immunocompromised murine models than vaccine strains utilized in smallpox eradication. The natural attenuation of TNX-801 and its ability to induce protective immunity via a single vaccination are promising and warrants further development.

MVA-BN vaccine effectiveness: A systematic review of real-world evidence in outbreak settings

BACKGROUND

Mpox is a disease endemic to Central and West Africa. It caused outbreaks in non-endemic countries, mainly in 2022. The endemic Democratic Republic of Congo is currently experiencing its largest outbreak yet. The vaccine Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) is approved for active immunization against mpox and smallpox. Since the outbreak in 2022, real-world studies have assessed MVA-BN's vaccine effectiveness (VE) against mpox, and this systematic literature review aims to summarize the most current evidence.

METHODS

Medline (via PubMed), Embase, and LILACS were searched, as well as grey literature sources and publications' bibliographies to identify observational studies published between 1/Jan/2022 and 28/Feb/2024 that estimate the VE of MVA-BN against mpox or provide risk measures that allow calculation of these VE estimates. Data were presented descriptively in tables and text; the methodological quality of included records was assessed using NHLBI/NIH quality assessment tools.

RESULTS

The literature search identified 16 records that fit the inclusion criteria. The studies took place in high-income countries and were heterogeneous in design, setting, and definition of at-risk populations. MVA-BN VE estimates against mpox infection were assessed. Where the study population was exclusively or primarily those receiving pre-exposure prophylactic vaccination, the adjusted VE estimates ranged from 35 % to 86 % (n = 8 studies) for one dose and from 66 % to 90 % (n = 5) for two doses. Where only post-exposure prophylactic vaccination was assessed, adjusted VE estimates were reported for one dose only at 78 % and 89 % (n = 2). Additionally, MVA-BN reduced the risk of mpox-related hospitalization in one study and the severity of mpox clinical manifestations in two studies.

CONCLUSIONS

Despite heterogeneity in study design, setting, and at-risk populations, the reported VE estimates against mpox infection demonstrated the effectiveness of one or two doses of MVA-BN in the context of an outbreak across multiple countries.

Global perspectives on smallpox vaccine against monkeypox: a comprehensive meta-analysis and systematic review of effectiveness, protection, safety and cross-immunogenicity

A large outbreak of monkeypox occurred in 2022, and most people lack immunity to orthopoxvirus. Smallpox vaccination is essential for preventing further smallpox outbreaks. This study evaluated the effectiveness, protection, safety, and cross-immunogenicity of smallpox vaccine in preventing monkeypox infection. PubMed, Embase, Scopus, and Web of Science were searched from database inception to 10 March 2024. We included studies involving "monkeypox virus" and "vaccinations", and excluded reviews, animal studies, and articles with missing or duplicate data. A total of 37 studies with 57,693 participants were included in the final analysis. The effectiveness data showed that monkeypox infection rates were lower in the smallpox-vaccinated group than in the unvaccinated group (risk ratio [RR]: 0.46; 95% confidence interval [CI]: 0.31-0.68). The protection data showed that smallpox vaccination effectively reduced the risk of severe monkeypox infection (RR: 0.61; 95% CI: 0.42-0.87). Third-generation vaccines showed greater efficacy (RR: 0.36, 95% CI: 0.22-0.56) than first-generation vaccines. The number of doses of smallpox vaccine has no significant effect on monkeypox. Safety data showed that adverse reactions after smallpox vaccination were mainly mild and included local erythema, swelling, induration, itching, and pain. Meanwhile, we found that smallpox vaccination could induce the production of neutralizing antibodies against monkeypox. Our findings offer compelling evidence supporting the clinical application of the smallpox vaccine for preventing monkeypox and advocate that high-risk groups should be prioritized for receiving one dose of the smallpox vaccine if the vaccine stockpile is low.

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).

Viral genetics and transmission dynamics in the second wave of mpox outbreak in Portugal and forecasting public health scenarios

In 2023, a second wave of the global mpox epidemic, which is mainly affecting men who have sex with men (MSM), was observed in some countries. Herein, we benefited from a large viral sequence sampling (76/121; 63%) and vast epidemiological data to characterise the re-emergence and circulation of the Monkeypox virus (MPXV) in Portugal during 2023. We also modelled transmission and forecasted public health scenarios through a compartmental susceptible-exposed-infectious-recovered (SEIR) model. Our results suggest that the 2023 mpox wave in Portugal resulted from limited introduction(s) of MPXV belonging to C.1.1 sublineage, hypothetically from Asia, followed by sustained viral transmission and potential exportation to other countries. We estimated that the contribution of the MSM high sexual activity group to mpox transmission was 120 (95% CrI: 30-3553) times higher than that of the low sexual activity group. However, among the high sexual activity group, vaccinated individuals likely contributed approximately eight times less [0.123 (95% CrI: 0.068-0.208)] than the unvaccinated ones. Vaccination was also linked to potential reduced disease severity, with a Mpox Severity Score of 6.0 in the vaccinated group compared to 7.0 in unvaccinated individuals. Scenario analysis indicated that transmission is highly sensitive to sexual behaviour, projecting that a slight increase in the MSM sub-population with high sexual activity can trigger new mpox waves. This study strongly supports that continued vaccination, targeted awareness among risk groups and routine genomic epidemiology is needed to anticipate and respond to novel MPXV threats (e.g. global dissemination of clade I viruses).

Mpox Clinical Presentation, Diagnostic Approaches, and Treatment Strategies: A Review

Importance

A global outbreak of clade IIb Monkeypox virus (MPXV) infections spread rapidly across at least 118 countries resulting in a Public Health Emergency of International Concern (PHEIC) from July 2022 to May 2023. This outbreak affected more than 99 000 persons worldwide and caused more than 33 000 infections and 60 deaths in the US. In 2024, there have been approximately 200 new infections per month in the US. On August 14, 2024, the World Health Organization declared mpox a PHEIC for a second time due to a rapid increase in infections with clade I MPXV in Central Africa.

Observations

Mpox is primarily acquired through direct skin to skin contact with MPXV. With clade IIb MPXV, infections are most commonly associated with sexual activity among individuals who are gay, bisexual, and other men who have sex with men. After a median incubation period of 7 to 10 days, prodromal symptoms include fever (62%-72%), lymphadenopathy (56%-86%), myalgias (31%-55%), malaise (23%-57%), and headache (25%-55%). Skin lesions progress through 4 well-defined stages (macules, papules, vesicles, and pustules) over 2 to 4 weeks. Clade IIb MPXV is typically a self-limited illness with a low mortality rate (<0.2% in the US); however, severe illness and death may occur in immunocompromised individuals, especially those with advanced HIV (CD4 count <200 cells/μL). Mpox should be suspected in patients with potential exposure to MPXV who have skin lesions, and the diagnosis is confirmed with polymerase chain reaction testing of lesions. Management is supportive and focuses on skin care and symptom relief with analgesics. While no antiviral treatments are currently approved for mpox by the US Food and Drug Administration, several therapeutics, such as tecovirimat, brincidofovir, and vaccinia immune globulin intravenous, are available through expanded access programs or clinical trials. Vaccination with the 2-dose Modified Vaccinia Ankara-Bavarian Nordic vaccine is recommended for high-incidence populations and has an efficacy of 66% to 86%.

Conclusions and Relevance

Mpox is a viral infection transmitted primarily through close skin to skin contact that typically causes a self-resolving illness but can result in severe illness and death in immunocompromised individuals. First-line therapy is supportive care, although patients with severe mpox infection may be treated with advanced therapeutics. Mpox vaccination is effective and, if available, should be offered to individuals at risk of exposure to mpox.

Decline of Mpox Antibody Responses After Modified Vaccinia Ankara-Bavarian Nordic Vaccination

This study assesses mpox-specific immune responses for 12 months after MVA-BN vaccination.

Serological Evidence of Mpox Virus Infection During Peak Mpox Transmission in New York City, July to August 2022

BACKGROUND

The extent to which infections may have been undetected in an epicenter of the 2022 mpox outbreak is unknown.

METHODS

A serosurvey (July and August 2022) assessed the seroprevalence and correlates of mpox infection among a diverse sample of asymptomatic patients with no prior mpox diagnoses and no known histories of smallpox or mpox vaccination. We present seropositivity stratified by participant characteristics collected via survey.

RESULTS

Two-thirds of 419 participants were cismen (281 of 419), of whom 59.1% (166 of 281) reported sex with men (MSM). The sample also included 109 ciswomen and 28 transgender/gender nonconforming/nonbinary individuals. Overall seroprevalence was 6.4% (95% confidence interval [CI], 4.1%-8.8%); 3.7% among ciswomen (95% CI, 1.0%-9.1%), 7.0% among cismen with only ciswomen partners (95% CI, 2.0%-11.9%), and 7.8% among MSM (95% CI, 3.7%-11.9%). There was little variation in seroprevalence by race/ethnicity, age group, HIV status, or number of recent sex partners. No participants who reported close contact with mpox cases were seropositive. Among participants without recent mpox-like symptoms, 6.3% were seropositive (95% CI, 3.6%-9.0%).

CONCLUSIONS

Approximately 1 in 15 vaccine-naive people in our study had antibodies to mpox during the height of the NYC outbreak, indicating the presence of asymptomatic infections that could contribute to ongoing transmission.

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.