Reduced Risk for Mpox After Receipt of 1 or 2 Doses of JYNNEOS Vaccine Compared with Risk Among Unvaccinated Persons - 43 U.S. Jurisdictions, July 31-October 1, 2022

Serologic responses to the MVA-based JYNNEOS mpox vaccine in a cohort of participants from the District of Columbia (D.C.)

We assessed early antibody responses after two doses of JYNNEOS (IMVANEX) mpox vaccine in the District of Columbia (D.C.) in persons at high risk for mpox without characteristic lesions or rash. Participants with PCR mpox negative specimens (oral swab, blood, and/or rectal swab) on the day of receipt of the first vaccine dose and who provided a baseline (day 0) serum sample and at least one serum sample at ∼28, ∼42-56 days, or 180 days post vaccination were included in this analysis. Orthopoxvirus (OPXV)-specific IgG and IgM ELISAs and neutralizing antibody titers were performed, and longitudinal serologic responses were examined. Based on participants' IgG and IgM antibody levels at baseline, they were categorized as naïve or non-naïve. Linear mixed effects regression models were conducted to determine if IgG antibody response over time varied by age, sex, HIV status, and route of administration for both naïve and non-naïve participants. Among both naïve and non-naïve participants IgG seropositivity rates increased until day 42-56, with 89.4 % of naïve and 92.1 % of non-naïve participants having detectable IgG antibodies. The proportion of naive participants with detectable IgG antibodies declined by day 180 (67.7 %) but remained high among non-naïve participants (94.4 %). Neutralizing antibody titers displayed a similar pattern, increasing initially post vaccination but declining by day 180 among naïve participants. There were no significant serologic response differences by age, sex, or HIV status. Serologic response did vary by route of vaccine administration, with those receiving a combination of intradermal and subcutaneous doses displaying significantly higher IgG values than those receiving both doses intradermally. These analyses provide initial insights into the immunogenicity of a two-dose JYNNEOS PEP regimen in individuals at high risk of mpox exposure in the United States.

Mpox in people with HIV: A narrative review

OBJECTIVE

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

RECENT FINDINGS

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

CONCLUSION

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

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.

Predicting vaccine effectiveness for mpox

The Modified Vaccinia Ankara vaccine developed by Bavarian Nordic (MVA-BN) was widely deployed to prevent mpox during the 2022 global outbreak. This vaccine was initially approved for mpox based on its reported immunogenicity (from phase I/II trials) and effectiveness in animal models, rather than evidence of clinical efficacy. However, no validated correlate of protection after vaccination has been identified. Here we performed a systematic search and meta-analysis of the available data to test whether vaccinia-binding ELISA endpoint titer is predictive of vaccine effectiveness against mpox. We observe a significant correlation between vaccine effectiveness and vaccinia-binding antibody titers, consistent with the existing assumption that antibody levels may be a correlate of protection. Combining this data with analysis of antibody kinetics after vaccination, we predict the durability of protection after vaccination and the impact of dose spacing. We find that delaying the second dose of MVA-BN vaccination will provide more durable protection and may be optimal in an outbreak with limited vaccine stock. Although further work is required to validate this correlate, this study provides a quantitative evidence-based approach for using antibody measurements to predict the effectiveness of mpox vaccination.

Addressing mpox at a Frontline Community Health Center: Lessons for the Next Outbreak

The 2022 mpox (formerly monkeypox) outbreak affected predominantly men who have sex with men (MSM), likely through sexual transmission, which resulted in institutions specializing in sexual health being at the frontlines of the mpox outbreak. Fenway Health in Boston serves close to 10 000 MSM annually, which includes more than 2400 MSM who are living with HIV and 3320 MSM with active HIV preexposure prophylaxis (PrEP) prescriptions. We report on the programs implemented and changes to clinical practice at Fenway Health during the mpox outbreak. Fenway Health diagnosed its first case of mpox in June 2022 and treated this patient with tecovirimat. In early July 2022, Fenway Health administered its first dose of the Jynneos vaccine under the Emergency Use Authorization for protection against mpox. As of October 6, 2022, 69 people had tested positive for the mpox virus at Fenway Health. Among the 69 people who tested positive, 43 (62.3%) self-identified as male, with the remaining not reporting a sex or gender identity, and 40 (58.0%) reported their sexual orientation as gay or bisexual. Twenty-five people (36.2%) were treated with tecovirimat. As of October 30, 2022, Fenway Health had administered 6376 doses of the Jynneos vaccine. The programmatic changes involved in rollout and scale-up of vaccination, treatment, and community outreach services at Fenway Health during the 2022 mpox outbreak that we describe here could inform strategies to address subsequent outbreaks.

Safety and immunogenicity of a novel trivalent recombinant MVA-based equine encephalitis virus vaccine: A Phase 1 clinical trial

BACKGROUND

Three encephalitic alphaviruses-western, eastern, and Venezuelan equine encephalitis virus (WEEV, EEEV and VEEV)-can cause severe disease and have the potential to be used as biological weapons. There are no approved vaccines for human use. A novel multivalent MVA-BN-WEV vaccine encodes the envelope surface proteins of the 3 viruses and is thereby potentially able to protect against them all, as previously demonstrated in animal models. This first-in-human study assessed the safety, tolerability, and immunogenicity of MVA-BN-WEV vaccine in healthy adult participants.

METHODS

Forty-five participants were enrolled into 3 dose groups (1 × 10E7 Inf.U, 1 × 10E8 Inf.U, and 2 × 10E8 Inf.U), received 2 doses 4 weeks apart, and were then monitored for 6 months.

RESULTS

The safety profile of MVA-BN-WEV was acceptable at all administered doses, with incidence of local solicited AEs increased with increasing dose and no other clinically meaningful differences between dose groups. One SAE (Grade 2 pleural effusion) was reported in the lowest dose group and assessed as possibly related. No AEs resulted in death or led to withdrawal from the second vaccination or from the trial. The most common local solicited AE was injection site pain, and general solicited AEs were headache, fatigue, and myalgia. MVA-BN-WEV induced humoral immune responses; WEEV-, EEEV- and VEEV-specific neutralizing antibody responses peaked 2 weeks following the second vaccination, and the magnitude of these responses increased with dose escalation. The highest dose resulted in seroconversion of all (100 %) participants for WEEV and VEEV and 92.9 % for EEEV, 2 weeks following second vaccination, and durability was observed for 6 months. MVA-BN-WEV induced cellular immune responses to VEEV E1 and E2 (EEEV and WEEV not tested) and a dose effect for peptide pool E2.

CONCLUSION

The study demonstrated that MVA-BN-WEV is well tolerated, induces immune responses, and is suitable for further development.

CLINICAL TRIAL REGISTRY NUMBER

NCT04131595.

Mpox vaccination and treatment: a systematic review

The Human monkeypox virus (mpox) belongs to the Poxviridae family, characterized by double-stranded DNA. A 2022 outbreak, notably prevalent among men who have sex with men, was confirmed by the World Health Organization. To understand shifting prevalence patterns and clinical manifestations, we conducted a systematic review of recent animal and human studies. We comprehensively searched PubMed, Scopus, Web of Science, Cochrane Library, and Clinicaltrials.gov, reviewing 69 relevant articles from 4,342 screened records. Our analysis highlights Modified Vaccinia Ankara - Bavarian Nordic (MVA-BN)'s potential, though efficacy concerns exist. Tecovirimat emerged as a prominent antiviral in the recent outbreak. However, limited evidence underscores the imperative for further clinical trials in understanding and managing monkeypox.

Human monkeypox virus: Epidemiologic review and research progress in diagnosis and treatment

Monkeypox virus (MPXV) is responsible for causing a zoonotic disease called monkeypox (mpox), which sporadically infects humans in West and Central Africa. It first infected humans in 1970 and, along with the variola virus, belongs to the genus Orthopoxvirus in the poxvirus family. Since the World Health Organization declared the MPXV outbreak a "Public Health Emergency of International Concern" on July 23, 2022, the number of infected patients has increased dramatically. To control this epidemic and address this previously neglected disease, MPXV needs to be better understood and reevaluated. In this review, we cover recent research on MPXV, including its genomic and pathogenic characteristics, transmission, mutations and mechanisms, clinical characteristics, epidemiology, laboratory diagnosis, and treatment measures, as well as prevention of MPXV infection in light of the 2022 and 2023 global outbreaks. The 2022 MPXV outbreak has been primarily associated with close intimate contact, including sexual activity, with most cases diagnosed among men who have sex with men. The incubation period of MPXV infection usually lasts from 6 to 13 days, and symptoms include fever, muscle pains, headache, swollen lymph nodes, and a characteristic painful rash, including several stages, such as macules, papules, blisters, pustules, scabs, and scab shedding involving the genitals and anus. Polymerase chain reaction (PCR) is usually used to detect MPXV in skin lesion material. Treatment includes supportive care, antivirals, and intravenous vaccinia immune globulin. Smallpox vaccines have been designed with four givens emergency approval for use against MPXV infection.

Intriguing insight into unanswered questions about Mpox: exploring health policy implications and considerations

The 2022 multi-country Monkeypox (Mpox) outbreak has added concerns to scientific research. However, unanswered questions about the disease remain. These unanswered questions lie in different aspects, such as transmission, the affected community, clinical presentations, infection and prevention control and treatment and vaccination. It is imperative to address these issues to stop the spread and transmission of disease. We documented unanswered questions with Mpox and offered suggestions that could help put health policy into practice. One of those questions is why gay, bisexual or other men who have sex with men (gbMSM) are the most affected community, underscoring the importance of prioritizing this community regarding treatment, vaccination and post-exposure prophylaxis. In addition, destigmatizing gbMSM and implementing community-based gbMSM consultation and action alongside ethical surveillance can facilitate other preventive measures such as ring vaccination to curb disease transmission and track vaccine efficacy. Relevant to that, vaccine and drug side effects have implied the questionability of their use and stimulated the importance of health policy development regarding expanded access and off-label use, expressing the need for safe drug and vaccine development manufacturing. The possibility of reverse zoonotic has also been raised, thus indicating the requirement to screen not only humans, but also their related animals to understand the real magnitude of reverse zoonosis and its potential risks. Implementing infection prevention and control measures to stop the virus circulation at the human-animal interface that includes One Health approach is essential.

Effectiveness of Modified Vaccinia Ankara-Bavaria Nordic Vaccination in a Population at High Risk of Mpox: A Spanish Cohort Study

BACKGROUND

With more than 7500 cases reported since April 2022, Spain has experienced the highest incidence of mpox in Europe. From 12 July onward, the modified vaccinia Ankara-Bavaria Nordic (MVA-BN) smallpox vaccine was offered as pre-exposure prophylaxis for those receiving pre-exposure prophylaxis for human immunodeficiency virus (HIV-PrEP). Our aim was to assess the effectiveness of 1 dose of MVA-BN vaccine as pre-exposure prophylaxis against mpox virus (MPXV) infection in persons on HIV-PrEP.

METHODS

National retrospective cohort study between 12 July and 12 December 2022. Individuals aged ≥18 years receiving HIV-PrEP as of 12 July with no previous MPXV infection or vaccination were eligible. Each day, we matched individuals receiving a first dose of vaccine and unvaccinated controls of the same age and region. We used a Kaplan-Meier estimator, calculated risk ratios (RR) and vaccine effectiveness (VE = [1 - RR]x100).

RESULTS

We included 5660 matched pairs, with a median follow-up of 62 days (interquartile range, 24-97). Mpox cumulative incidence was 5.6 per 1000 (25 cases) in unvaccinated and 3.5 per 1000 (18 cases) in vaccinated. No effect was found during days 0-6 post-vaccination (VE, -38.3; 95% confidence interval [CI], -332.7 to 46.4), but VE was 65% at ≥7 days (95% CI, 22.9 to 88.0) and 79% at ≥14 days (95% CI, 33.3 to 100.0) post-vaccination.

CONCLUSIONS

One dose of MVA-BN vaccine offered protection against mpox in most-at-risk population shortly after the vaccination. Further studies need to assess the VE of a second dose and the duration of protection over time.

Single-dose Effectiveness of Mpox Vaccine in Quebec, Canada: Test-negative Design With and Without Adjustment for Self-reported Exposure Risk

INTRODUCTION

During the 2022 mpox outbreak, the province of Quebec, Canada, prioritized first doses for pre-exposure vaccination of people at high mpox risk, delaying second doses due to limited supply. We estimated single-dose mpox vaccine effectiveness (VE) adjusting for virus exposure risk based only on surrogate indicators available within administrative databases (eg, clinical record of sexually transmitted infections) or supplemented by self-reported risk factor information (eg, sexual contacts).

METHODS

We conducted a test-negative case-control study between 19 June and 24 September 2022. Information from administrative databases was supplemented by questionnaire collection of self-reported risk factors specific to the 3-week period before testing. Two study populations were assessed: all within the administrative databases (All-Admin) and the subset completing the questionnaire (Sub-Quest). Logistic regression models adjusted for age, calendar-time and exposure-risk, the latter based on administrative indicators only (All-Admin and Sub-Quest) or with questionnaire supplementation (Sub-Quest).

RESULTS

There were 532 All-Admin participants, of which 199 (37%) belonged to Sub-Quest. With exposure-risk adjustment based only on administrative indicators, single-dose VE estimates were similar among All-Admin and Sub-Quest populations at 35% (95% confidence interval [CI]:-2 to 59) and 30% (95% CI:-38 to 64), respectively. With adjustment supplemented by questionnaire information, the Sub-Quest VE estimate increased to 65% (95% CI:1-87), with overlapping confidence intervals.

CONCLUSIONS

Using only administrative data, we estimate one vaccine dose reduced the mpox risk by about one-third; whereas, additionally adjusting for self-reported risk factor information revealed greater vaccine benefit, with one dose instead estimated to reduce the mpox risk by about two-thirds. Inadequate exposure-risk adjustment may substantially under-estimate mpox VE.

Immunogenicity and reactogenicity of modified vaccinia Ankara pre-exposure vaccination against mpox according to previous smallpox vaccine exposure and HIV infection: prospective cohort study

Background

Pre-exposure vaccination with MVA-BN has been widely used against mpox to contain the 2022 outbreak. Many countries have defined prioritized strategies, administering a single dose to those historically vaccinated for smallpox, to achieve quickly adequate coverage in front of low supplies. Using epidemiological models, real-life effectiveness was estimated at approximately 36%-86%, but no clinical trials were performed. Few data on MVA-BN immunogenicity are currently available, and there are no established correlates of protection. Immunological response in PLWH in the context of the 2022 outbreak was also poorly described.

Methods

Blood samples were collected from participants eligible for pre-exposure MVA-BN vaccination before (T1) receiving a full course of vaccine (single-dose for vaccine-experienced or smallpox-primed and two-dose for smallpox vaccine-naïve or smallpox non-primed) and one month after the last dose (T2 and T3, respectively). MPXV-specific IgGs were measured by in-house immunofluorescence assay, using 1:20 as screening dilution, MPXV-specific nAbs by 50% plaque reduction neutralization test (PRNT50, starting dilution 1:10), and IFN-γ-producing specific T cells to MVA-BN vaccine, by ELISpot assay. Paired or unpaired t-test and Wilcoxon or Mann-Whitney test were used to analyse IgG and nAbs, and T-cell response, as appropriate. The probability of IgG and nAb response in vaccine-experienced vs. vaccine-naïve was estimated in participants not reactive at T1. The McNemar test was used to evaluate vaccination's effect on humoral response both overall and by smallpox vaccination history. In participants who were not reactive at T1, the proportion of becoming responders one month after full-cycle completion by exposure groups was compared by logistic regression and then analysed by HIV status strata (interaction test). The response was also examined in continuous, and the Average Treatment Effect (ATE) of the difference from baseline to schedule completion according to previous smallpox vaccination was estimated after weighting for HIV using a linear regression model. Self-reports of adverse effects following immunization (AEFIs) were prospectively collected after the first MVA-BN dose (T1). Systemic (S-AEFIs: fatigue, myalgia, headache, GI effects, chills) and local (L-AEFIs: redness, swelling, pain) AEFIs were graded as absent (grade 0), mild (1), moderate (2), or severe (3). The maximum level of severity for S-AEFIs and L-AEFIs ever experienced over the 30 days post-dose by vaccination exposure groups were analysed using a univariable multinomial logistic regression model and after adjusting for HIV status; for each of the symptoms, we also compared the mean duration by exposure group using an unpaired t-test.

Findings

Among the 164 participants included, 90 (54.8%) were smallpox vaccine-experienced. Median age was 49 years (IQR 41-55). Among the 76 (46%) PLWH, 76% had a CD4 count >500 cells/μL. There was evidence that both the IgG and nAbs titers increased after administration of the MVA-BN vaccine. However, there was no evidence for a difference in the potential mean change in humoral response from baseline to the completion of a full cycle when comparing primed vs. non-primed participants. Similarly, there was no evidence for a difference in the seroconversion rate after full cycle vaccination in the subset of participants not reactive for nAbs at T1 (p = 1.00 by Fisher's exact test). In this same analysis and for the nAbs outcome, there was some evidence of negative effect modification by HIV (interaction p-value = 0.17) as primed people living with HIV (PLWH) showed a lower probability of seroconversion vs. non-primed, and the opposite was seen in PLWoH. When evaluating the response in continuous, we observed an increase in T-cell response after MVA-BN vaccination in both primed and non-primed. There was evidence for a larger increase when using the 2-dose vs. one-dose strategy with a mean difference of -2.01 log2 (p ≤ 0.0001), after controlling for HIV. No evidence for a difference in the risk of developing any AEFIs of any grade were observed by exposure group, except for the lower risk of grade 2 (moderate) fatigue, induration and local pain which was lower in primed vs. non-primed [OR 0.26 (0.08-0.92), p = 0.037; OR 0.30 (0.10-0.88), p = 0.029 and OR 0.19 (0.05-0.73), p = 0.015, respectively]. No evidence for a difference in symptom duration was also detected between the groups.

Interpretation

The evaluation of the humoral and cellular response one month after the completion of the vaccination cycle suggested that MVA-BN is immunogenic and that the administration of a two-dose schedule is preferable regardless of the previous smallpox vaccination history, especially in PLWH, to maximize nAbs response. MVA-BN was safe as well tolerated, with grade 2 reactogenicity higher after the first administration in vaccine-naïve than in vaccine-experienced individuals, but with no evidence for a difference in the duration of these adverse effects. Further studies are needed to evaluate the long-term duration of immunity and to establish specific correlates of protection.

Funding

The study was supported by the National Institute for Infectious Disease Lazzaro Spallanzani IRCCS "Advanced grant 5 × 1000, 2021" and by the Italian Ministry of Health "Ricerca Corrente Linea 2".

Mpox in people living with HIV

PURPOSE OF REVIEW

The 2022 global outbreak of mpox disproportionally affected people with HIV (PWH). We review the data on the presentation, treatment, and prevention of mpox in PWH.

RECENT FINDINGS

Most PWH with mpox had a mild and self-limiting illness, no different to people without HIV. A higher rate of rectal symptoms has been reported among PWH and those with advanced HIV disease were at higher risk of severe disease, hospitalization, and death. Treatment with antivirals was widely used in hospitalized patients without any randomized control trial data to support its use and without any data specifically in PWH. Use of smallpox vaccines to prevent mpox is safe in PWH regardless of CD4+ cell count. There is limited data on efficacy in those with lower CD4+ cell count and on long-term protective efficacy.

SUMMARY

PWH should be offered vaccination against mpox in line with national guidelines. PWH should be individually risk-assessed for severe mpox, based on their CD4+ cell count and co-morbidities and ideally recruited into treatment trials to build an evidence base on efficacy. HIV and other sexually transmitted infection testing should be offered to all people diagnosed with mpox.

Mpox in people with past infection or a complete vaccination course: a global case series

BACKGROUND

Since May, 2022, a large global outbreak of human mpox (formerly known as monkeypox) has predominantly affected men who have sex with men. The strain responsible, Clade IIb, has mutated substantially from precursors originating from the 2017-18 outbreak in Nigeria. Immunity to smallpox, another orthopoxvirus, via previous infection or vaccination provides lifelong immunity. However, since the 2022 mpox outbreak, recent clusters were described in individuals with presumed immunity through recent infection or vaccination. We aim to describe the epidemiological and clinical characteristics of mpox in individuals with past infection or vaccination to improve the understanding of this disease in the setting of previous immunity.

METHODS

In this global case series, international collaborators from nine countries provided data on individuals with PCR-confirmed mpox after documented previous infection or vaccination between May 11, 2022, and June 30, 2023. We excluded cases that could not confirm vaccination status or cases with partial immunisation or any doses received before the current multi-national mpox outbreak (cutoff date May 1, 2022). Data were collected via a case report spreadsheet that reported on dates of infection and vaccination, route of immunisation, demographic characteristics, clinical findings, HIV status, concomitant sexually transmitted infections, and markers of disease severity (mpox severity score system). We describe case epidemiology, clinical course, and mpox severity scores; all analyses were descriptive.

FINDINGS

We report mpox infections in 37 gay and bisexual men who have sex with men: seven individuals had mpox reinfections, 29 individuals had mpox infections that occurred after two appropriately spaced Modified Vaccinia Ankara-Bavarian Nordic vaccine courses, and one individual had an infection that met the criteria for both reinfection and infection after vaccination. The median age of individuals was 36 years (IQR 30-45; range 21-58). Those with natural immunity after initial infection had a shorter disease course with less mucosal disease upon reinfection than with their initial infection. Infections post-vaccination were characterised by few lesions, little mucosal disease, and minimal analgesia requirements; two people received oral tecovirimat. Overall, there were no deaths, no bacterial superinfections, and all individuals were managed in the ambulatory clinic with one hospital admission for a necrotising neck lesion.

INTERPRETATION

The epidemiology of people with mpox reinfection or infection post-vaccination was similar to other published cohorts during the 2022 outbreak-predominantly young, sexually active gay and bisexual men who have sex with men. Clinical features and outcomes of repeat infection and infection after vaccination appear to be less clinically severe than those described in 2022 case literature. Specifically, compared with the 2022 case series, these individuals in the present study had fewer confluent lesions, less mucosal involvement, reduced analgesia requirement, and fewer admissions. Natural immunity and vaccine-induced immunity are not fully protective against mpox infection. However, in this small series both disease duration and severity appear to be reduced.

FUNDING

None.

No evidence of asymptomatic monkeypox infection in a highly sexually active MSM population in Austria

BACKGROUND

The 2022 outbreak of monkeypox virus (MPXV) revealed new transmission routes. Incidence declined sharply in September 2022, and it remains unclear whether MPXV is circulating in asymptomatic individuals because of increased immunity.

OBJECTIVES

Our study aimed to assesss the number of asymtomatic MPXV carriers in individuals at high risk for STI.

METHODS

We analysed anal samples from asymptomatic highly sexually active men who have sex with men for the presence of MPXV.

RESULTS

We detected a high number of concomitant sexually transmitted infections but did not find a single sample with MPXV.

CONCLUSIONS

Our results indicate that the general recommendation to implement screening for MPXV is not currently justified.

Strategic and scientific contributions of human challenge trials for vaccine development: facts versus fantasy

The unprecedented speed of delivery of SARS-CoV-2 pandemic vaccines has redefined the limits for all vaccine development. Beyond the aspirational 100-day timeline for tomorrow's hypothetical pandemic vaccines, there is a sense of optimism that development of other high priority vaccines can be accelerated. Early in the COVID-19 pandemic, an intense and polarised academic and public discourse arose concerning the role of human challenge trials for vaccine development. A case was made for human challenge trials as a powerful tool to establish early proof-of-concept of vaccine efficacy in humans, inform vaccine down selection, and address crucial knowledge gaps regarding transmission, pathogenesis, and immune protection. We review the track record of human challenge trials contributing to the development of vaccines for 19 different pathogens and discuss relevant limitations, barriers, and pitfalls. This Review also highlights opportunities for efforts to broaden the scope and boost the effects of human challenge trials, to accelerate all vaccine development.

Clinical review of human mpox

BACKGROUND

Historically, human mpox was predominantly a zoonotic disease occurring more frequently in rural children in Africa and characterized by a largely self-limiting febrile centrifugal monomorphic rash illness. However, the 2022 mpox global outbreak has shown that the disease is changing in many ways, including sustained human-to-human transmission via sexual contact, novel clinical presentations, and adverse associations between mpox and advanced HIV.

OBJECTIVES

The aim of this paper is to review the traditional and emerging clinical aspects of human mpox and provide updated information on the clinical course and outcome of the disease.

SOURCES

We searched electronic databases including PubMed and Google Scholar and identified relevant published literature on mpox.

CONTENT

The clinical presentation of human mpox is influenced by the route of infectious exposure, the strain and dose of the infecting virus, and the host immune system. Exposure to the virus can result in sub-clinical or clinical diseases of variable severity. Infections caused by clade I viral strains are more severe than class IIa and IIb strains, which are associated with a milder febrile rash illness, and with anogenital skin lesions in clade IIb infections. Most cases of mpox recover entirely within 2-4 weeks after onset of illness and a few develop skin-related sequelae. Overall, people with advanced HIV infection, children <5 years of age, and pregnant women may present with more severe disease and higher case fatalities.

IMPLICATIONS

The continued endemicity of the classical mpox in Africa, the emergence of a new clinical form of the disease during the 2022 global outbreak, and the adverse associations between advanced HIV and mpox have implications for the surveillance, clinical diagnosis, and management of human mpox.

Acceptance and timeliness of post-exposure vaccination against mpox in high-risk contacts, Amsterdam, the Netherlands, May-July 2022

BACKGROUND

May 2022, several countries reported mpox outbreaks among men-who-have-sex-with-men. In the Netherlands, high-risk contacts were offered the third-generation smallpox vaccine as post-exposure-prophylaxis (PEP) within 4 but maximum 14 days after exposure. We investigated their PEP acceptance, timeliness of uptake and development of mpox for the region of the Public Health Service (PHS) Amsterdam.

METHODS

High-risk contacts identified during 20 May-22 July 2022 were included. Contacts were followed-up 21 days after exposure and classified as: no patient (no mpox symptoms or orthopoxvirus PCR-negative) or mpox patient (clinically suspected mpox or orthopoxvirus PCR-positive). We calculated time intervals between date of last exposure and first PHS consultation, PEP administration, and symptom onset.

RESULTS

Two-hundred-ninety contacts were at high-risk of mpox predominantly due to sexual and/or direct skin-skin contact (212/290, 73 %). First PHS consultation was a median of 5 (IQR 3, 7) days after exposure, at which point 26/290 (9 %) contacts were ineligible for PEP. 84 % (223/264) of contacts eligible for PEP, received PEP within a median of 6 (IQR 3, 8) days after exposure. Of 282 contacts (missing outcome n = 8) 38 (14 %) developed mpox a median of 7 (IQR 5, 12) days after exposure, of whom 50 % (19/38) developed mpox before their first PHS consultation. Among contacts eligible for PEP, 2/38 (5 %) unvaccinated and 16/218 (7 %) vaccinated contact developed mpox.

CONCLUSIONS

PEP acceptance among contacts of mpox patients was high. However, PEP timeliness was inadequate. Half of contacts received PEP 6 or more days after exposure, and half of contacts who developed mpox had an onset prior to their first PHS consultation. Estimating PEP vaccine effectiveness is problematic due to the timeliness of PEP and the time it takes to generate vaccine-induced immunity. It is important to assess how PEP timeliness may improve and to promote pre-exposure vaccination to control mpox outbreaks.

Systematic Review on the Efficacy, Effectiveness, Safety, and Immunogenicity of Monkeypox Vaccine

BACKGROUND

The variation in the reported vaccine safety and effectiveness could contribute to the high rates of vaccine hesitancy among the general population and healthcare workers in areas where monkeypox (mpox) is circulating. In this review, our objective was to evaluate the safety, immunogenicity, effectiveness, and efficacy of the mpox vaccines.

METHODS

An extensive search for articles across multiple databases was performed, including searching six databases (PubMed Central, PubMed Medline, Scopus, Web of Science, Cochrane, ProQuest), two pre-print databases (European PMC Preprint and MedRxiv), and Google Scholar.

RESULTS

A total of 4290 citations were retrieved from the included databases. Following the removal of duplicates and the initial screening of records, a total of 36 studies were included into the analysis. Additionally, we identified five more studies through manual searches, resulting in a total of 41 eligible articles for qualitative synthesis. The study findings revealed that mpox vaccines demonstrate the ability to generate adequate antibodies; however, their effectiveness may decrease over time, exhibiting varying safety profiles. Most of the included studies consistently reported substantial levels of effectiveness and efficacy against mpox. Interestingly, the number of vaccine doses administered was found to influence the degree of immunogenicity, subsequently impacting the overall effectiveness and efficacy of the vaccines. Furthermore, we found that smallpox vaccines exhibited a form of cross-protection against mpox.

CONCLUSIONS

Vaccines can be used to prevent mpox and effectively control its spread.

A Review of the Past, Present, and Future of the Monkeypox Virus: Challenges, Opportunities, and Lessons from COVID-19 for Global Health Security

Monkeypox, a rare but significant zoonotic and orthopoxviral disease, has garnered increasing attention due to its potential for human-to-human transmission and its recent resurgence in multiple countries throughout Europe, North America, and Oceania. The disease has emerged as a novel threat to the global health systems that are still striving to recover from the major shocks of the COVID-19 pandemic. The unusual manifestation of the illness highlights a substantial knowledge deficit and necessitates the immediate development of a public health action strategy, considering the epidemiological differences observed in the ongoing outbreak and the appearance of cases in non-endemic nations. This literature review aims to synthesize existing knowledge on monkeypox, encompassing its historical context, etiology, epidemiology, surveillance, prevention, transmission, clinical presentation, diagnosis, treatments, and recent outbreak. Particular attention is given to both advances and gaps in our understanding of monkeypox, and we point toward future directions for research and intervention efforts as pertains to vaccine development and distribution. Lastly, we will also review the recent outbreak through a sociopolitical lens as relates to decision-making strategies, especially given the lessons learned from COVID-19.

Characteristics of Mpox Infections in Louisiana in the 2022 Outbreak

The 2022 outbreak of mpox in Louisiana was limited to just >300 cases, perhaps an unexpected outcome given the state's high rates of HIV and other sexually transmitted infections (STIs). We aimed to describe the local outbreak within two health centers in the New Orleans region, partnering with the Louisiana Department of Health to offer additional statewide data. We reviewed charts of persons testing positive for mpox in New Orleans from July to November 2022 at two local health centers that together accounted for half of local cases. We abstracted data on HIV status, immune function [CD4 count, viral load (VL)], antiretroviral therapy regimen, symptoms and severity of infection, vaccination status, and whether tecovirimat was administered. We present local data relative to statewide data (July 2022-January 2023). Of 103 individuals in our network for whom charts were reviewed, 96 (93%) identified as male, 52 (50%) were Black, and 69 (67%) had HIV, including 12 (17%) with uncontrolled HIV (CD4 < 200 cells/mm3 or VL >200 copies/mL). The most common presenting symptoms were rash (n = 71, 69%), fever (n = 36, 35%), and rectal pain (n = 33, 32%). Of six (6%) patients hospitalized, four (67%) were persons with HIV (PWH). Two were hospitalized for severe mpox infection with >100 lesions at presentation; both were PWH, and one had uncontrolled infection. Across the state, 307 cases have been identified and 24 have been hospitalized. Of those hospitalized, 18 (75%) were PWH, including 9 (50%) with uncontrolled HIV. The demographic data from Louisiana, a state with high prevalence of STIs and HIV/AIDS, are consistent with prior reports describing the 2022 mpox outbreak. Our results contribute to accumulating data on the severity of infection in individuals with HIV-related immunocompromise.

Efficacy of smallpox vaccines against Mpox infections in humans

The Mpox virus (MPXV) is endemic in certain countries in Central and West Africa, where several mammalian species, especially rodents, are natural reservoirs. However, the MPXV can infect nonhuman primates and cause zoonotic infections in humans after close contact with an infected animal. Human-to-human transmission of MPXV can also occur through direct close contact with an infected individual or infected materials. In May 2022 an initial cluster of human Mpox cases was identified in the UK, with the first case confirmed in a patient who had recently travelled to Nigeria. The infection subsequently spread via human-to-human transmission within the UK and Mpox cases began to appear in many other countries around the world where the MPXV is not endemic. No specific treatments for MPXV infection in humans are available. However, data from studies undertaken in Zaire in the 1980s revealed that those with a history of smallpox vaccination during the global smallpox eradication campaign also had good cross-protection against MPXV infection. However, the vaccines used during the global eradication campaign are no longer available. During the 2022 global Mpox outbreak over a million doses of the Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) smallpox vaccine were offered either as pre or postexposure prophylaxis to those at high risk of MPXV infection. Here, we review what has been learned about the efficacy of smallpox vaccines in reducing the incidence of MPXV infections in high-risk close contacts.

Development of a novel serological assay for the detection of mpox infection in vaccinated populations

In 2022 the World Health Organization declared a Public Health Emergency for an outbreak of mpox, the zoonotic Orthopoxvirus (OPV) affecting at least 104 nonendemic locations worldwide. Serologic detection of mpox infection is problematic, however, due to considerable antigenic and serologic cross-reactivity among OPVs and smallpox-vaccinated individuals. In this report, we developed a high-throughput multiplex microsphere immunoassay using a combination of mpox-specific peptides and cross-reactive OPV proteins that results in the specific serologic detection of mpox infection with 93% sensitivity and 98% specificity. The New York State Non-Vaccinia Orthopoxvirus Microsphere Immunoassay is an important tool to detect subclinical mpox infection and understand the extent of mpox spread in the community through retrospective analysis.

Real-world effectiveness of monkeypox vaccines: a systematic review

A systematic review was conducted to investigate and understand the real-world effectiveness of smallpox vaccines against mpox during 2022 outbreaks. The effectiveness of MVA-BN was estimated to be 87% [95% confidence interval (CI): 84–90%] for one-dose and 89% (95% CI: 78–100%) for two-dose vaccination. The next-generation vaccines are recommended for future preparedness.

Update on Mpox: a brief narrative review

Mpox (formerly Monkeypox), a neglected tropical disease once confined to Central and West Africa, emerged as a global epidemic outbreak in May, 2022 with 87,529 cases reported as of May, 23, 2023. It predominantly affected men (96.2%) who have sex with men (84-100%), although other transmission routes have been reported, including occupational exposure and vertical transmission. Concomitant HIV infection has been recorded in 21-46.9% and pre-exposure prophylaxis against HIV infection has been reported in 11-57% of published cases. The current outbreak clinical presentation differs from endemic cases with prodromal symptoms that could be absent: the number of lesions is generally low, with skin lesions predominantly localised in the ano-genital areas and frequent lesions present in different stages of progression (i.e., asynchronous). Asymptomatic Mpox infection can occur in 1.8-6.5% of at-risk subjects. People living with HIV with severe immunodeficiency (less than 100 CD4+ lymphocytes per microliter) are at risk of more severe clinical manifestations and death. According to a systematic review and meta-analysis, the hospitalisation rate is around 6% and the observed case-fatality rate is less than 0.1%. Tecovirimat is the drug of choice for treating severe cases although there is no evidence of efficacy from randomised controlled trials. Immunization with a live non-replicating vaccine (JYNNEOS) effectively reduces the disease's incidence.

Mpox: an updated review of dermatological manifestations in the current outbreak

Mpox is a disease caused by a double-stranded DNA orthopoxvirus discovered in 1958. In 2022, an outbreak on an unprecedented scale marked its transition from neglected, zoonotic disease circulating almost exclusively within African borders to sexually transmitted infection (STI) of international concern. Although phylogenetic evidence suggests progressive evolution from the strain associated with the 2018 outbreak in Nigeria, epidemiological links with previous cases have still not been completely elucidated. Clinically, mpox presents with systemic symptoms, such as fever, headache, malaise and a characteristic cutaneous eruption, similar to that of cognate viruses (e.g. smallpox). Mpox pseudopustules evolve through several stages, including umbilication and crusting, and resolve in the span of 2-3 weeks. The hallmarks that set the 2022 outbreak apart from classic mpox were a disproportionate number of cases occurring in men who have sex with men, an often localized cutaneous picture and a significant burden in terms of concomitant STIs. Investigations into the disease pathogenesis, related immune response, clinical and dermoscopic features, in addition to studies aimed at defining novel management strategies, have advanced mpox knowledge considerably. Herein, recent findings on mpox are reviewed, with a keen focus on dermatological manifestations and their implications in the current diagnostic scenario, reinforcing the pivotal role of dermatologists in managing suspect cases and preventing further spread of the contagion.

Immunogenicity and Safety of Modified Vaccinia Ankara (MVA) Vaccine-A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Prevention of mpox has become an important public health interest. We aimed to evaluate the safety and immunogenicity of the Modified Vaccinia Ankara (MVA) vaccine. We conducted a systematic review and meta-analysis of randomized-controlled trials (RCTs) comparing MVA versus no intervention, placebo, or another vaccine. Outcomes included safety and immunogenicity outcomes. We also performed a systematic review of RCTs evaluating various MVA regimens. Fifteen publications were included in the quantitative meta-analysis. All but one (ACAM2000) compared MVA with placebo. We found that cardiovascular adverse events following two MVA doses were significantly more common compared to placebo (relative risk [RR] 4.07, 95% confidence interval [CI] 1.10-15.10), though serious adverse events (SAEs) were not significantly different. Following a single MVA dose, no difference was demonstrated in any adverse event outcomes. Seroconversion rates were significantly higher compared with placebo after a single or two doses. None of the RCTs evaluated clinical effectiveness in preventing mpox. This meta-analysis provides reassuring results concerning the immunogenicity and safety of MVA. Further studies are needed to confirm the immunogenicity of a single dose and its clinical effectiveness. A single vaccine dose may be considered according to vaccine availability, with preference for two doses.

Clinical Features, Antiviral Treatment, and Patient Outcomes: A Systematic Review and Comparative Analysis of the Previous and the 2022 Mpox Outbreaks

BACKGROUND

This study aims to comparatively analyze clinical features, treatment, and patient outcomes between the previous and the 2022 mpox (monkeypox) outbreaks.

METHODS

Five bibliographic databases were searched for studies reporting clinical features, management, and patient outcomes of mpox. Systematic review and meta-analysis were performed.

RESULTS

In total, 73 studies were included in the systematic review, of which 33 studies were subjected to meta-analysis. Previous outbreaks substantially affected children, whereas the 2022 outbreak primarily affected male adults, of which 94.66% (95% confidence interval [CI], 88.03-98.95) were men who have sex with men. Furthermore, 72.47% (95% CI, 51.04-89.71) reported high-risk sexual activity and the overall human immunodeficiency virus (HIV) prevalence was 37.65% (95% CI, 30.09-45.50). Skin lesions remain the typical symptom; however, their anatomic distribution differed. Systemic manifestations were common, but rectal pain was unique to the 2022 outbreak. The estimated overall fatality during past outbreaks in Africa was 4.61% (95% CI, 2.39%-7.35%), whereas 6.34% (95% CI, 3.35%-10.10%) of patients from the 2022 outbreak required hospitalization. Antiviral treatment, in particular tecovirimat, has been prescribed for a subset of patients, but the efficacy remains inconclusive.

CONCLUSIONS

These findings are important for better understanding the disease and guiding adequate response to mpox outbreaks.

Mpox and HIV: a Narrative Review

PURPOSE OF REVIEW

We reviewed the available literature on mpox in People with HIV (PWH). We highlight special considerations of mpox infection related to epidemiology, clinical presentation, diagnostic and treatment considerations, prevention, and public health messaging in PWH.

RECENT FINDINGS

During the 2022 mpox outbreak, PWH were disproportionally impacted worldwide. Recent reports suggest that the disease presentation, management, and prognosis of these patients, especially those with advanced HIV disease, can widely differ from those without HIV-associated immunodeficiency. Mpox can often be mild and resolve on its own in PWH with controlled viremia and higher CD4 counts. However, it can be severe, with necrotic skin lesions and protracted healing; anogenital, rectal, and other mucosal lesions; and disseminated organ systems involvement. Higher rates of healthcare utilization are seen in PWH. Supportive, symptomatic care and single or combination mpox-directed antiviral drugs are commonly used in PWH with severe mpox disease. Data from randomized clinical control trials on the efficacy of therapeutic and preventive tools against mpox among PWH are needed to better guide clinical decisions.

Demographic Disparities in Mpox Vaccination Series Completion, by Route of Vaccine Administration - California, August 9, 2022-March 31, 2023

In August 2022, the Food and Drug Administration authorized JYNNEOS vaccine (modified vaccinia Ankara vaccine, Bavarian Nordic), a 2-dose series used for the prevention of Monkeypox virus infection, to be administered via a dose-sparing intradermal route, in addition to the previously authorized subcutaneous route. The California Department of Public Health investigated whether demographic disparities in vaccination series completion varied by route of administration of the recipient's first dose. Among California residents who received their first dose during August 9, 2022-March 31, 2023, a total of 59.8% received a second dose. Series completion was highest among non-Hispanic White persons (64.1%), persons aged ≥65 years (72.6%), and adults with male sex assignment at birth (62.1%); series completion was lowest among non-Hispanic Black or African American persons (51.3%), persons aged 18-24 years (42.9%), and adults assigned female sex at birth (42.8%). When the first dose was received by subcutaneous administration, overall series completion was 58.8% compared with 60.2% when the first dose was administered intradermally. Odds of series completion across all race and ethnicity groups, persons aged 18-64 years, community health conditions, and persons assigned male sex at birth were not greater when the first dose was administered subcutaneously compared with intradermally. Intradermal use of JYNNEOS vaccine did not lower overall 2-dose series completion rates. Continued efforts are needed to ensure persons at risk for Monkeypox virus infection receive both recommended doses.

Characteristics of Mpox Vaccine Recipients Among a Sample of Men Who Have Sex With Men With Presumed Exposure to Mpox

ABSTRACT

Mpox vaccination is recommended for persons exposed to or at risk for mpox. Approximately 25% of an online sample of men who have sex with men (MSM) with presumed mpox exposure were vaccinated (≥1 dose). Vaccination was higher among younger MSM, MSM concerned about mpox, or MSM reporting sexual risk behaviors. Incorporating mpox vaccination into routine sexual health care and increasing 2-dose vaccination uptake is essential to preventing mpox acquisition, improving MSM sexual health, and averting future mpox outbreaks.

Vaccine Effectiveness of JYNNEOS against Mpox Disease in the United States

BACKGROUND

In the United States, more than 30,000 cases of mpox (formerly known as monkeypox) had occurred as of March 1, 2023, in an outbreak disproportionately affecting transgender persons and gay, bisexual, and other men who have sex with men. In 2019, the JYNNEOS vaccine was approved for subcutaneous administration (0.5 ml per dose) to prevent mpox infection. On August 9, 2022, an emergency use authorization was issued for intradermal administration (0.1 ml per dose); however, real-world effectiveness data are limited for either route.

METHODS

We conducted a case-control study based on data from Cosmos, a nationwide Epic electronic health record (EHR) database, to assess the effectiveness of JYNNEOS vaccination in preventing medically attended mpox disease among adults. Case patients had an mpox diagnosis code or positive orthopoxvirus or mpox virus laboratory result, and control patients had an incident diagnosis of human immunodeficiency virus (HIV) infection or a new or refill order for preexposure prophylaxis against HIV infection between August 15, 2022, and November 19, 2022. Odds ratios and 95% confidence intervals were estimated from conditional logistic-regression models, adjusted for confounders; vaccine effectiveness was calculated as (1 - odds ratio for vaccination in case patients vs. controls) × 100.

RESULTS

Among 2193 case patients and 8319 control patients, 25 case patients and 335 control patients received two doses (full vaccination), among whom the estimated adjusted vaccine effectiveness was 66.0% (95% confidence interval [CI], 47.4 to 78.1), and 146 case patients and 1000 control patients received one dose (partial vaccination), among whom the estimated adjusted vaccine effectiveness was 35.8% (95% CI, 22.1 to 47.1).

CONCLUSIONS

In this study using nationwide EHR data, patients with mpox were less likely to have received one or two doses of JYNNEOS vaccine than control patients. The findings suggest that JYNNEOS vaccine was effective in preventing mpox disease, and a two-dose series appeared to provide better protection. (Funded by the Centers for Disease Control and Prevention and Epic Research.).

Predictors of Mpox vaccine uptake among sexual and gender minority young adults living in Illinois: Unvaccinated vs. double vs. single dose vaccine recipients

INTRODUCTION

The 2022 global outbreak of Monkeypox virus (Mpox), which has primarily spread through the sexual networks of sexual and gender minority (SGM) individuals, has introduced new public health challenges. While an efficacious Mpox vaccine is in active circulation, few Mpox vaccine studies have examined its uptake among SGM groups. The aims of this study were to investigate (a) the prevalence of Mpox vaccine uptake among SGM and (b) the contextual, Mpox-disease specific, and Mpox-vaccine specific factors associated with Mpox vaccine among SGM.

METHODS

We conducted a cross-sectional survey in Illinois, USA in September 2022; 320 young SGM completed self-administered questionnaires. Multinomial logistic regression was used to assess the contextual, Mpox-disease specific, and Mpox-vaccine specific factors associated with Mpox vaccine uptake. Adjusted Odds Ratios (aORs) and 95 % Confidence Intervals (CI) are reported.

RESULTS

Approximately 50 % of the SGM participants included in this study had received at least their first dose of the Mpox vaccine. Multinomial regression analysis showed that individuals who had recently experienced food insecurity, had higher degrees of fear of social rejection due to Mpox acquisition, and were more Mpox-vaccine hesitant were more likely to be unvaccinated. Conversely, knowing people who have contracted Mpox, having higher formal educational attainment, having higher degrees of Mpox-related internalized heterosexism, and being more concerned about one's safety regarding Mpox morbidity were more likely to be double-dosers.

CONCLUSION

Approximately 50 % of the SGMs included in this study received at least their first dose of the Mpox vaccine; however, only one-quarter of participants completed the recommended 2-dose Mpox regimen. Our findings indicate that socioeconomic stability, fear of social rejection due to disease acquisition, and Mpox-specific vaccine hesitancy may be important structural targets to consider when developing vaccine-uptake prevention and intervention strategies tailored to the needs of sexual and gender minorities.

Complement-dependent mpox-virus-neutralizing antibodies in infected and vaccinated individuals

Mpox virus (MPXV) caused a multi-country outbreak in non-endemic areas in 2022. Following historic success of smallpox vaccination with vaccinia virus (VACV)-based vaccines, the third generation modified vaccinia Ankara (MVA)-based vaccine was used as prophylaxis for MPXV, but its effectiveness remains poorly characterized. Here, we applied two assays to quantify neutralizing antibodies (NAbs) in sera from control, MPXV-infected, or MVA-vaccinated individuals. Various levels of MVA NAbs were detected after infection, historic smallpox, or recent MVA vaccination. MPXV was minimally sensitive to neutralization. However, addition of complement enhanced detection of responsive individuals and NAb levels. Anti-MVA and -MPXV NAbs were observed in 94% and 82% of infected individuals, respectively, and 92% and 56% of MVA vaccinees, respectively. NAb titers were higher in individuals born before 1980, highlighting the impact of historic smallpox vaccination on humoral immunity. Altogether, our results indicate that MPXV neutralization is complement dependent and uncover mechanisms underlying vaccine effectiveness.

Perceptions and Intention to Get Vaccinated against Mpox among the LGBTIQ+ Community during the 2022 Outbreak: A Cross-Sectional Study in Peru

Vaccination against mpox can control the outbreak by targeting high-risk groups such as the LGBTIQ+ community. The aim of the study was to evaluate the perceptions and intentions to get vaccinated against mpox among the LGBTIQ+ community in Peru. We conducted a cross-sectional study from 1 November 2022 to 17 January 2023 in Peru. We included individuals over 18 years old, belonging to the LGBTIQ+ community, and residing in the departments of Lima and Callao. To evaluate the factors associated with the intention to be vaccinated, we used Poisson regression with robust variance to create a multivariate model. The study comprised 373 individuals who self-identified as members of the LGBTIQ+ community. The participants had a mean age of 31 years (SD ± 9), with 85.0% males and 75.3% reporting to be homosexual men. The majority (88.5%) expressed their intention to receive the vaccine against mpox. Believing that the vaccine is safe was associated with a higher intention to be vaccinated (aPR: 1.24; 95% CI: 1.02 to 1.50; p = 0.028). Our study population showed a high level of mpox vaccination intent. Educational campaigns reinforcing the concept of vaccine safety should be conducted to increase the intention and possibly the vaccination rate in the LGBTIQ+ community.

The CDC Domestic Mpox Response - United States, 2022-2023

Monkeypox (mpox) is a serious viral zoonosis endemic in west and central Africa. An unprecedented global outbreak was first detected in May 2022. CDC activated its emergency outbreak response on May 23, 2022, and the outbreak was declared a Public Health Emergency of International Concern on July 23, 2022, by the World Health Organization (WHO),* and a U.S. Public Health Emergency on August 4, 2022, by the U.S. Department of Health and Human Services.^† A U.S. government response was initiated, and CDC coordinated activities with the White House, the U.S. Department of Health and Human Services, and many other federal, state, and local partners. CDC quickly adapted surveillance systems, diagnostic tests, vaccines, therapeutics, grants, and communication systems originally developed for U.S. smallpox preparedness and other infectious diseases to fit the unique needs of the outbreak. In 1 year, more than 30,000 U.S. mpox cases were reported, more than 140,000 specimens were tested, >1.2 million doses of vaccine were administered, and more than 6,900 patients were treated with tecovirimat, an antiviral medication with activity against orthopoxviruses such as Variola virus and Monkeypox virus. Non-Hispanic Black (Black) and Hispanic or Latino (Hispanic) persons represented 33% and 31% of mpox cases, respectively; 87% of 42 fatal cases occurred in Black persons. Sexual contact among gay, bisexual, and other men who have sex with men (MSM) was rapidly identified as the primary risk for infection, resulting in profound changes in our scientific understanding of mpox clinical presentation, pathogenesis, and transmission dynamics. This report provides an overview of the first year of the response to the U.S. mpox outbreak by CDC, reviews lessons learned to improve response and future readiness, and previews continued mpox response and prevention activities as local viral transmission continues in multiple U.S. jurisdictions (Figure).

Estimated Effectiveness of JYNNEOS Vaccine in Preventing Mpox: A Multijurisdictional Case-Control Study - United States, August 19, 2022-March 31, 2023

As of March 31, 2023, more than 30,000 monkeypox (mpox) cases had been reported in the United States in an outbreak that has disproportionately affected gay, bisexual, and other men who have sex with men (MSM) and transgender persons (1). JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic) was approved by the Food and Drug Administration (FDA) in 2019 for the prevention of smallpox and mpox via subcutaneous injection as a 2-dose series (0.5 mL per dose, administered 4 weeks apart) (2). To expand vaccine access, an Emergency Use Authorization was issued by FDA on August 9, 2022, for dose-sparing intradermal injection of JYNNEOS as a 2-dose series (0.1 mL per dose, administered 4 weeks apart) (3). Vaccination was available to persons with known or presumed exposure to a person with mpox (postexposure prophylaxis [PEP]), as well as persons at increased risk for mpox or who might benefit from vaccination (preexposure mpox prophylaxis [PrEP]) (4). Because information on JYNNEOS vaccine effectiveness (VE) is limited, a matched case-control study was conducted in 12 U.S. jurisdictions,^† including nine Emerging Infections Program sites and three Epidemiology and Laboratory Capacity sites,^§ to evaluate VE against mpox among MSM and transgender adults aged 18-49 years. During August 19, 2022-March 31, 2023, a total of 309 case-patients were matched to 608 control patients. Adjusted VE was 75.2% (95% CI = 61.2% to 84.2%) for partial vaccination (1 dose) and 85.9% (95% CI = 73.8% to 92.4%) for full vaccination (2 doses). Adjusted VE for full vaccination by subcutaneous, intradermal, and heterologous routes of administration was 88.9% (95% CI = 56.0% to 97.2%), 80.3% (95% CI = 22.9% to 95.0%), and 86.9% (95% CI = 69.1% to 94.5%), respectively. Adjusted VE for full vaccination among immunocompromised participants was 70.2% (95% CI = -37.9% to 93.6%) and among immunocompetent participants was 87.8% (95% CI = 57.5% to 96.5%). JYNNEOS is effective at reducing the risk for mpox. Because duration of protection of 1 versus 2 doses remains unknown, persons at increased risk for mpox exposure should receive the 2-dose series as recommended by the Advisory Committee on Immunization Practices (ACIP),^¶ regardless of administration route or immunocompromise status.

Effectiveness of JYNNEOS Vaccine Against Diagnosed Mpox Infection - New York, 2022

In 2022, an international Monkeypox virus outbreak, characterized by transmission primarily through sexual contact among gay, bisexual, and other men who have sex with men (MSM), resulted in 375 monkeypox (mpox) cases in the state of New York outside of New York City (NYC).*^,† The JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic), licensed by the U.S. Food and Drug Administration (FDA) against mpox as a 2-dose series, with doses administered 4 weeks apart,^§ was deployed in a national vaccination campaign.^¶ Before this outbreak, evidence to support vaccine effectiveness (VE) against mpox was based on human immunologic and animal challenge studies (1-3). New York State Department of Health (NYSDOH) conducted a case-control study to estimate JYNNEOS VE against diagnosed mpox in New York residents outside of NYC, using data from systematic surveillance reporting. A case-patient was defined as a man aged ≥18 years who received a diagnosis of mpox during July 24-October 31, 2022. Contemporaneous control patients were men aged ≥18 years with diagnosed rectal gonorrhea or primary syphilis and a history of male-to-male sexual contact, without mpox. Case-patients and control patients were matched to records in state immunization systems. JYNNEOS VE was estimated as 1 - odds ratio (OR) x 100, and JYNNEOS vaccination status (vaccinated versus unvaccinated) at the time of diagnosis was compared, using conditional logistic regression models that adjusted for week of diagnosis, region, patient age, and patient race and ethnicity. Among 252 eligible mpox case-patients and 255 control patients, the adjusted VE of 1 dose (received ≥14 days earlier) or 2 doses combined was 75.7% (95% CI = 48.5%-88.5%); the VE for 1 dose was 68.1% (95% CI = 24.9%-86.5%) and for 2 doses was 88.5% (95% CI = 44.1%-97.6%). These findings support recommended 2-dose JYNNEOS vaccination consistent with CDC and NYSDOH guidance.

Unexpectedly higher levels of anti-orthopoxvirus neutralizing antibodies are observed among gay men than general adult population

BACKGROUND

The confirmed cases in the current outbreak of Monkeypox are predominantly identified in the networks of men who have sex with men (MSM). The preexisting antibodies may profoundly impact the transmission of monkeypox virus (MPXV), however the current-day prevalence of antibodies against MPXV among gay men is not well characterized.

METHODS

A cohort of gay men (n = 326) and a cohort of the general adult population (n = 295) were enrolled in this study. Binding antibodies responses against MPXV/vaccinia and neutralizing antibody responses against vaccinia virus (Tiantan strain) were measured. The antibody responses of these two cohorts were then compared, as well as the responses of individuals born before and in/after 1981 (when the smallpox vaccination ceased in China). Finally, the correlation between the anti-MPXV antibody responses and the anti-vaccinia antibody responses, and the associations between preexisting anti-orthopoxvirus antibody responses and the diagnosed sexually transmitted infections (STIs) in the MSM cohort were analyzed separately.

RESULTS

Our data showed that binding antibodies against MPXV H3, A29, A35, E8, B6, M1 proteins and vaccinia whole-virus lysate could be detected in individuals born both before and in/after 1981, of which the prevalence of anti-vaccinia binding antibodies was significantly higher among individuals born before 1981 in the general population cohort. Moreover, we unexpectedly found that the positive rates of binding antibody responses against MPXV H3, A29, A35, E8 and M1 proteins were significantly lower among individuals of the MSM cohort born in/after 1981, but the positive rates of anti-MPXV B6 and anti-vaccinia neutralizing antibody responses were significantly higher among these individuals compared to those of age-matched participants in the general population cohort. Additionally, we demonstrated that the positive and negative rates of anti-MPXV antibody responses were associated with the anti-vaccinia antibody responses among individuals born before 1981 in the general population cohort, but no significant association was observed among individuals born in/after 1981 in both cohorts. The positive rates of both the binding and the neutralizing antibody responses were comparable between individuals with and without diagnosed STIs in the MSM cohort.

CONCLUSIONS

Anti-MPXV and anti-vaccinia antibodies could be readily detected in an MSM cohort and a general population cohort. And a higher level of anti-vaccinia neutralizing antibody responses was observed among individuals who did not get vaccinated against smallpox in the MSM cohort compared to age-matched individuals in the general population cohort.

Fair domestic allocation of monkeypox virus countermeasures

Countermeasures for mpox (formerly known as monkeypox), primarily vaccines, have been in limited supply in many countries during outbreaks. Equitable allocation of scarce resources during public health emergencies is a complex challenge. Identifying the objectives and core values for the allocation of mpox countermeasures, using those values to provide guidance for priority groups and prioritisation tiers, and optimising allocation implementation are important. The fundamental values for the allocation of mpox countermeasures are: preventing death and illness; reducing the association between death or illness and unjust disparities; prioritising those who prevent harm or mitigate disparities; recognising contributions to combating an outbreak; and treating similar individuals similarly. Ethically and equitably marshalling available countermeasures requires articulating these fundamental objectives, identifying priority tiers, and recognising trade-offs between prioritising the people at the highest risk of infection and the people at the highest risk of harm if infected. These five values can provide guidance on preferable priority categories for a more ethically sound response and suggest methods for optimising allocation of countermeasures for mpox and other diseases for which countermeasures are in short supply. Properly marshalling available countermeasures will be crucial for future effective and equitable national responses to outbreaks.

CROI 2023: Epidemiology, Diagnosis, and Management of MPox

The 2023 Conference on Retroviruses and Opportunistic Infections (CROI) emphasized emerging infectious diseases such as COVID-19 and mpox. Despite emerging from countries in which it was endemic only 9 months before the conference, mpox was well covered, with more than 60 presentations addressing various topics. There was a focus on the rapid development and implementation of tests to reduce the time to diagnosis, as well as multiplex panels to increase the accuracy of differential diagnosis. Presenters also highlighted the ability to diagnose mpox from multiple compartments, such as with rectal and pharyngeal swabs, and provided crucial information on the duration of positivity that may impact isolation requirements. Clinical experiences were described, including risk factors for severe disease and syndemic management. High rates of concomitant sexually transmitted infection (STI) were reported. Finally, prevention was a key topic, with presenters pointing to the contributions of individual behavioral changes and vaccine efficacy to reducing new cases.

Development of a Novel Serological Assay for the Detection of Mpox Infection in Vaccinated Populations

In 2022 the World Health Organization declared a Public Health Emergency for an outbreak of mpox, the zoonotic Orthopoxvirus (OPV) affecting at least 103 non-endemic locations world-wide. Serologic detection of mpox infection is problematic, however, due to considerable antigenic and serologic cross-reactivity among OPVs and smallpox-vaccinated individuals. In this report, we developed a high-throughput multiplex microsphere immunoassay (MIA) using a combination of mpox-specific peptides and cross-reactive OPV proteins that results in the specific serologic detection of mpox infection with 93% sensitivity and 98% specificity. The New York State Non-Vaccinia Orthopoxvirus Microsphere Immunoassay is an important diagnostic tool to detect subclinical mpox infection and understand the extent of mpox spread in the community through retrospective analysis.

Monkeypox (Mpox) requires continued surveillance, vaccines, therapeutics and mitigating strategies

The widespread outbreak of the monkeypox virus (MPXV) recognized in 2022 poses new challenges for public healthcare systems worldwide. With more than 86,000 people infected, there is concern that MPXV may become endemic outside of its original geographical area leading to repeated human spillover infections or continue to be spread person-to-person. Fortunately, classical public health measures (e.g., isolation, contact tracing and quarantine) and vaccination have blunted the spread of the virus, but cases are continuing to be reported in 28 countries in March 2023. We describe here the vaccines and drugs available for the prevention and treatment of MPXV infections. However, although their efficacy against monkeypox (mpox) has been established in animal models, little is known about their efficacy in the current outbreak setting. The continuing opportunity for transmission raises concerns about the potential for evolution of the virus and for expansion beyond the current risk groups. The priorities for action are clear: 1) more data on the efficacy of vaccines and drugs in infected humans must be gathered; 2) global collaborations are necessary to ensure that government authorities work with the private sector in developed and low and middle income countries (LMICs) to provide the availability of treatments and vaccines, especially in historically endemic/enzootic areas; 3) diagnostic and surveillance capacity must be increased to identify areas and populations where the virus is present and may seed resurgence; 4) those at high risk of severe outcomes (e.g., immunocompromised, untreated HIV, pregnant women, and inflammatory skin conditions) must be informed of the risk of infection and be protected from community transmission of MPXV; 5) engagement with the hardest hit communities in a non-stigmatizing way is needed to increase the understanding and acceptance of public health measures; and 6) repositories of monkeypox clinical samples, including blood, fluids, tissues and lesion material must be established for researchers. This MPXV outbreak is a warning that pandemic preparedness plans need additional coordination and resources. We must prepare for continuing transmission, resurgence, and repeated spillovers of MPXV.

Mpox vaccine and infection-driven human immune signatures

Background

Mpox (formerly known as monkeypox) outbreaks outside endemic areas peaked in July 2022, infecting > 85,000 people and raising concerns about our preparedness against this emerging viral pathogen. Licensed and approved for mpox, the JYNNEOS vaccine has fewer side effects than previous smallpox vaccines and demonstrated efficacy against mpox infection in humans. Comparing JYNNEOS vaccine- and mpox-induced immunity is imperative to evaluate JYNNEOS' immunogenicity and inform vaccine administration and design.

Methods

We examined the polyclonal serum (ELISA) and single B cell (heavy chain gene and transcriptome data) antibody repertoires and T cells (AIM and ICS assays) induced by the JYNNEOS vaccine as well as mpox infection.

Findings

Gene-level plasmablast and antibody responses were negligible and JYNNEOS vaccinee sera displayed minimal binding to recombinant mpox proteins and native proteins from the 2022 outbreak strain. In contrast, recent mpox infection (within 20-102 days) induced robust serum antibody responses to A29L, A35R, A33R, B18R, and A30L, and to native mpox proteins, compared to vaccinees. JYNNEOS vaccine recipients presented comparable CD4 and CD8 T cell responses against orthopox peptides to those observed after mpox infection.

Interpretation

JYNNEOS immunization does not elicit a robust B cell response, and its immunogenicity may be mediated by T cells.

Funding

Research reported in this publication was supported, in part, by the National Cancer Institute of the National Institutes of Health under Award Number U54CA267776, U19AI168631(VS), as well as institutional funds from the Icahn School of Medicine.

Possible Undetected Mpox Infection Among Persons Accessing Homeless Services and Staying in Encampments - San Francisco, California, October-November 2022

Monkeypox (mpox) is a disease caused by an Orthopoxvirus. The 2022 multinational outbreak, which began in May 2022, has spread primarily by close skin-to-skin contact, including through sexual contact. Persons experiencing homelessness have been disproportionately affected by severe mpox (1). However, mpox prevalence and transmission pathways among persons experiencing homelessness are not known, and persons experiencing homelessness have not been specifically recommended to receive mpox vaccine during the 2022 outbreak (2,3). During October 25-November 3, 2022, a CDC field team conducted an orthopoxvirus seroprevalence survey among persons accessing homeless services or staying in encampments, shelters, or permanent supportive housing in San Francisco, California that had noted at least one case of mpox or served populations at risk. During field team visits to 16 unique sites, 209 participants completed a 15-minute survey and provided a blood specimen. Among 80 participants aged <50 years who did not report smallpox or mpox vaccination or previous mpox infection, two (2.5%) had detectable antiorthopoxvirus immunoglobulin (Ig) G antibody. Among 73 participants who did not report mpox vaccination or previous mpox infection and who were tested for IgM, one (1.4%) had detectable antiorthopoxvirus IgM. Together, these results suggest that three possible undetected mpox infections occurred among a sample of persons experiencing homelessness, highlighting the need to ensure that community outreach and prevention interventions, such as vaccination, are accessible to this population.