Safety and Immunogenicity of Modified Vaccinia Ankara-Bavarian Nordic Smallpox Vaccine in Vaccinia-Naive and Experienced Human Immunodeficiency Virus-Infected Individuals: An Open-Label, Controlled Clinical Phase II Trial

Breakthrough Mpox Outbreak Investigation, the Delicate Balance Between Host Immune Response and Viral Immune Escape

BACKGROUND

Limited data are available on Mpox breakthrough infections.

PURPOSE

The purpose of this study is to investigate a Mpox breakthrough outbreak in 3 vaccinated individuals.

METHODS

Study participants provided informed consent. Serology testing was performed in one involved individual (ID-1) using an in-house assay detecting anti-orthopoxvirus IgG. Whole genome sequencing (WGS) was carried out and compared with the reference sequence ON563414.3 ( https://www.ncbi.nlm.nih.gov/nuccore/ON563414.3/ ).

RESULTS

Three individuals vaccinated with modified vaccinia Ankara-Bavaria Nordic contracted Mpox following one sexual intercourse event. One of them (ID-1) had received only one vaccine dose, while the other two were fully vaccinated. ID-1 presented to the sexual health clinic of the Universitair Ziekenhuis Brussel with proctitis related to Mpox. Despite one vaccination, serology testing Three months post vaccine showed absence of Mpox virus (MPXV) specific antibodies in ID-1. In contrast, 2 weeks after the sexual intercourse, seroconversion occurred. Whole genome sequencing of the isolated MPXV showed, compared with the reference sequence, a total of seven single nucleotide variants with four of them indicating protein amino-acid changes.

CONCLUSION

Incomplete MPXV vaccination as well as MPXV variants might result in breakthrough infections. Preventive measures, such as MPVX vaccination, could maintain immunity in individuals with higher risk of MPXV infection, and might lower disease severity.

Effectiveness of JYNNEOS vaccine against symptomatic mpox disease in adult men in Los Angeles County, August 29, 2022 to January 1, 2023

We describe real-world estimates of JYNNEOS vaccine effectiveness (VE) against symptomatic mpox in Los Angeles County (LAC). We conducted a retrospective cohort study of men aged ≥18 years residing in LAC who were at risk for mpox and eligible for the JYNNEOS vaccine from 5/19/2022 to 1/1/2023. Case demographics and route of JYNNEOS administration were obtained through vaccine administration data systems. HIV and sexually transmitted infection (STI) status was obtained through disease reporting systems for HIV and STI diagnoses in LAC. To estimate VE, we calculated weekly incidence of confirmed mpox for unvaccinated, partially vaccinated (episode date ≥14 days after first dose), and fully vaccinated (episode date ≥14 days after second dose) cohorts starting on 8/29/2022, when fully vaccinated coverage exceeded 3 %, and ending on 1/1/2023. Overall, 2,171 men had confirmed mpox, and 1,002 (46 %) of those were persons living with diagnosed HIV (PLWDH). 2,019 (93 %) mpox cases were unvaccinated, 114 (5 %) were partially vaccinated and 38 (2 %) were fully vaccinated. VE was 69 % (95 % CI 59-77) for partially vaccinated and 84 % (95 % CI 80-87) for fully vaccinated individuals. Among PLWDH, VE was 72 % (95 % CI 57-82) for fully vaccinated and 28 % (95 % CI -96 to 73) VE for partially vaccinated individuals. Among persons not living with diagnosed HIV, VE was 88 % (95 % CI 86-90) for fully vaccinated and 80 % (95 % CI 76-83) for partially vaccinated individuals. Of 111 individuals hospitalized with mpox, one was partially vaccinated, and the remaining were unvaccinated. Our results align with other published studies that reported that two doses of the JYNNEOS vaccine provided significant protection against symptomatic mpox.

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.

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.

A Quadrivalent mRNA Immunization Elicits Potent Immune Responses against Multiple Orthopoxviral Antigens and Neutralization of Monkeypox Virus in Rodent Models

The global outbreak of the 2022 monkeypox virus infection of humans and the 2023 documentation of a more virulent monkeypox in the Democratic Republic of the Congo raised public health concerns about the threat of human-to-human transmission of zoonotic diseases. Currently available vaccines may not be sufficient to contain outbreaks of a more transmissible and pathogenic orthopoxvirus. Development of a safe, effective, and scalable vaccine against orthopoxviruses to stockpile for future emergencies is imminent. In this study, we have developed an mRNA vaccine candidate, ALAB-LNP, expressing four vaccinia viral antigens A27, L1, A33, and B5 in tandem in one molecule, and evaluated the vaccine immunogenicity in rodent models. Immunization of animals with the candidate mRNA vaccine induced a potent cellular immune response and long-lasting antigen-specific binding antibody and neutralizing antibody responses against vaccinia virus. Strikingly, the sera from the vaccine-immunized mice cross-reacted with all four homologous antigens of multiple orthopoxviruses and neutralized monkeypox virus in vitro, holding promise for this mRNA vaccine candidate to be used for protection of humans from the infection of monkeypox and other orthopoxvirus.

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.

Molecular Virology of Orthopoxviruses with Special Reference to Monkeypox Virus

Poxviruses are large (200-450 nm) and enveloped viruses carrying double-stranded DNA genome with an epidermal cell-specific adaptation. The genus Orthopoxvirus within Poxviridae family constitutes several medically and veterinary important viruses including variola (smallpox), vaccinia, monkeypox virus (MPXV), and cowpox. The monkeypox disease (mpox) has recently emerged as a public health emergency caused by MPXV. An increasing number of human cases of MPXV have been documented in non-endemic nations without any known history of contact with animals brought in from endemic and enzootic regions, nor have they involved travel to an area where the virus was typically prevalent. Here, we review the MPXV replication, virus pathobiology, mechanism of viral infection transmission, virus evasion the host innate immunity and antiviral therapies against Mpox. Moreover, preventive measures including vaccination were discussed and concluded that cross-protection against MPXV may be possible using antibodies that are directed against an Orthopoxvirus. Despite the lack of a specialised antiviral medication, several compounds such as Cidofovir and Ribavirin warrant consideration against mpox.

Characterizing the acute antibody response of monkeypox and MVA-BN vaccine following an Australian outbreak

In response to the emergence of the monkeypox virus (MPXV) in Australia in May 2022, we developed and evaluated indirect immunofluorescence assays (IFA) for MPXV and Vaccinia virus (VACV) IgG and IgM antibodies using serum samples from patients with nucleic acid amplification test (NAAT)-confirmed mpox and uninfected unvaccinated controls. Additionally, 47 healthcare workers receiving two doses of the third-generation smallpox vaccine Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) undertook serial serum collection to describe the serological response to vaccination. MPXV antibodies were detected in 16/18 individuals with NAAT-confirmed mpox (sensitivity 0.89, specificity 1.00), and VACV antibodies were detected in 28/29 individuals who received two doses of MVA-BN vaccine (sensitivity 0.97, specificity 1.00). Detectable antibody in subjects historically vaccinated with early-generation vaccines against smallpox was found in 7/7 subjects, at a median of 48 years following vaccination. MPXV NAAT-positive patients with serum samples collected within the first 14 days after rash onset had detectable IgG and IgM in 9/12 and 5/12 of patients, respectively, with maintenance of IgG and disappearance of IgM titers after 60 days. While specificity was high when testing unvaccinated and uninfected subjects, significant cross-reactivity between MPXV and VACV antibodies was observed.

Poxvirus Vaccines: Past, Present, and Future

Smallpox was a significant cause of mortality for over three thousand years, amounting to 10% of deaths yearly. Edward Jenner discovered smallpox vaccination in 1796, which rapidly became a smallpox infection preventive practice throughout the world and eradicated smallpox infection by 1980. After smallpox eradication, monkeypox vaccines have been used primarily in research and in outbreaks in Africa, where the disease is endemic. In the present, the vaccines are being used for people who work with animals or in high-risk areas, as well as for healthcare workers treating patients with monkeypox. Among all orthopoxviruses (OPXV), monkeypox viral (MPXV) infection occurs mainly in cynomolgus monkeys, natural reservoirs, and occasionally causes severe multi-organ infection in humans, who were the incidental hosts. The first case of the present epidemic of MXPV was identified on May 7, 2022, and rapidly increased the number of cases. In this regard, the WHO declared the outbreak, an international public health emergency on July 23, 2022. The first monkeypox vaccine was developed in the 1960s by the US Army and was based on the vaccinia virus, which is also used in smallpox vaccines. In recent years, newer monkeypox vaccines have been developed based on other viruses such as Modified Vaccinia Ankara (MVA). These newer vaccines are safer and can provide longer-lasting immunity with fewer side effects. For the future, there is ongoing research to improve the current vaccines and to develop new ones. One notable advance has been the development of a recombinant vaccine that uses a genetically modified vaccinia virus to express monkeypox antigens. This vaccine has shown promising results in pre-clinical trials and is currently undergoing further testing in clinical trials. Another recent development has been the use of a DNA vaccine, which delivers genetic material encoding monkeypox antigens directly into cells. This type of vaccine has shown effectiveness in animal studies and is also undergoing clinical testing in humans. Overall, these recent advances in monkeypox vaccine development hold promise for protecting individuals against this potentially serious disease.

Viral blips and virologic failures following mpox vaccination with MVA-BN among people with HIV

OBJECTIVES

The study aim was to evaluate whether mpox vaccination with modified vaccinia Ankara-Bavarian Nordic (MVA-BN) may be associated with viral blips or confirmed virologic failures (CVF) in people with HIV (PWH) receiving antiretroviral therapy and the associated factors.

DESIGN

PWH who received MVA-BN, with HIV-RNA less than 50 copies/ml, and CD4 + lymphocytes at least 200 cells/μl in the 6 months prior to vaccination and at least 1 HIV-RNA determination within 3 months from vaccination.

METHODS

The primary outcome was occurrence of viral blips (1 HIV-RNA ≥50 copies/ml) and CVF (1 HIV-RNA ≥1000 copies/ml or ≥2 consecutive HIV-RNA ≥50 copies/ml) following MVA-BN. Changes in CD4 + and CD4 + /CD8 + were secondary outcomes. Residual viremia was defined as detectable HIV-RNA less than 50 copies/ml. PWH already vaccinated against smallpox received single-dose MVA-BN. Mann--Whitney rank-sum test or chi-square/Fisher's test applied.

RESULTS

Overall, 187 PWH were included: 147 received two doses of MVA-BN, 40 single-dose. Six viral blips [incidence rate = 1.59/100-person months of follow-up (PMFU), 95% confidence interval (95% CI) = 0.58-3.47], and three CVFs [incidence rate = 0.80/100-PMFU (95% CI = 0.16-2.33)] were observed. Two CVFs occurred at second dose with presence of detectable HIV-RNA following first one, with high compliance to antiretroviral therapy (ART). PWH with viral blips or CVFs had, prior to first vaccination, more frequently residual viremia [77% ( n  = 7) versus 35% ( n  = 62), P  = 0.01]. No differences in ART ( P  = 0.42) and number of MBA-BN doses ( P  = 0.40) was found. In two cases of CVFs, ART was changed; all VBs resolved within 1 month.

CONCLUSION

Although rare, viral blips and CVFs following MVA-BN vaccination among PWH receiving ART were identified. Close monitoring of HIV-RNA during mpox vaccination should be encouraged.

Mpox and HIV-Collision of Two Diseases

PURPOSE OF REVIEW

The global outbreak of mpox has brought renewed attention to a previously neglected disease which is particularly severe in people with underlying untreated HIV co-infection. For this population, the disease is progressive, severe, and often lethal. In this review, we examine the pathogenesis of mpox disease and its collision with co-existent HIV infection and discuss key considerations for management as well as emerging clinical dilemmas and areas for future research.

RECENT FINDINGS

Co-existent untreated HIV infection characterized by severe immunocompromise potentiates the nefarious effects of monkeypox virus infection leading to severe manifestations of mpox. Treating mpox in the context of HIV requires mpox-directed therapies, supportive care, and HIV-specific treatment to restore immune function. Preventative measures for PWH are like those in healthy individuals, but the effectiveness and durability of protection conferred by existing vaccines in PWH remain to be fully characterized. Mpox is an important opportunistic infection in PWH. Clinicians should be aware of the unique features of the disease in this population and approaches to care and management of mpox in PWH.

Update on the M-pox virus and safety measures taken against it globally

Globally, more than 50 countries have been affected by Monkey pox virus after COVID-19 has subsided. WHO declared "public health emergency of international concern" in year 2022 because of virus affecting 60,000 people in just one month that belonged to clade-IIb. Previously, it had been transmitted by body fluids, lesions and touching items, but fresh transmission is via sexual activity among bisexuals and man to man sex (MSM). New outbreaks reported compromised health status of confirmed cases with rectal pain, bleeding, tenesmus, pus or blood in stool, vomiting, proctitis and abdominal pain, which became alarming for entire world because of complications leading to bacterial skin infections, sepsis, encephalitis, hemorrhagic disease, blindness and pneumonia eventually. This virus has been further deteriorating unstable and unsustainable economy that requires dire attention. Strict preventive measures in terms of personal hygiene, pet and livestock health care, hospital contaminant disposal, good surveillance record, pre and post exposure vaccination, waste and water management could be only possible strategies to eliminate devastatingly dangerous M-pox outbreaks in this epic.

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

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

Epidemiological characteristics, clinical manifestations, and mental health status of human mpox cases: A multicenter cross-sectional study in China

Human mpox is occurring worldwide, however, evidence from the Asian Pacific Region is limited. In this multicenter cross-sectional study, information of confirmed mpox cases diagnosed between June 1 and July 31, 2023 in China. Information included demographic and epidemiological characteristics, and clinical manifestations, laboratory results, and mental health status of mpox cases. A total of 115 confirmed mpox cases were enrolled. All cases were men. A total of 102 (90.3%) identified as homosexual. The median age was 31.0 years (interquartile range 27.0-36.5). A total of 65 (56.5%) were HIV-positive, of whom 92.3% were receiving antiretroviral therapy (ART). A total of 19/39 (40.4%) had a CD4 cell count <500 cells/μL. Systemic features such as fever (73.0%), lymphadenopathies (49.6%), and myalgia (28.7%) were commonly observed. Skin lesions were present in all participants: 49.6% in the genital area and 27.0% in the perianal area. Vesicular rash (78.3%) and papular rash (44.3%) were the most common lesion morphologies. People living with HIV were more likely to have anxiety than those living without HIV. The majority of mpox cases had primary genital lesions and sexual activities before diagnosis, which supports the likelihood of sexual contact transmission. Guidelines on hospitalization and isolation protocols for mpox patients necessitate further confirmation.

Immunogenicity and Efficacy of Vaccination in People Living with Human Immunodeficiency Virus

People living with HIV (PLWH) remain at high risk of mortality and morbidity from vaccine-preventable diseases, even though antiretroviral therapy (ART) has restored life expectancy and general well-being. When, which, and how many doses of vaccine should be administered over the lifetime of PLWH are questions that have become clinically relevant. Immune responses to most vaccines are known to be impaired in PLWH. Effective control of viremia with ART and restored CD4+ T-cell count are correlated with an improvement in responsiveness to routine vaccines. However, the presence of immune alterations, comorbidities and co-infections may alter it. In this article, we provide a comprehensive review of the literature on immune responses to different vaccines in the setting of HIV infection, emphasizing the potential effect of HIV-related factors and presence of comorbidities in modulating such responses. A better understanding of these issues will help guide vaccination and prevention strategies for PLWH.

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.

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.

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.).

The Global Monkeypox (Mpox) Outbreak: A Comprehensive Review

Monkeypox (Mpox) is a contagious illness that is caused by the monkeypox virus, which is part of the same family of viruses as variola, vaccinia, and cowpox. It was first detected in the Democratic Republic of the Congo in 1970 and has since caused sporadic cases and outbreaks in a few countries in West and Central Africa. In July 2022, the World Health Organization (WHO) declared a public-health emergency of international concern due to the unprecedented global spread of the disease. Despite breakthroughs in medical treatments, vaccines, and diagnostics, diseases like monkeypox still cause death and suffering around the world and have a heavy economic impact. The 85,189 reported cases of Mpox as of 29 January 2023 have raised alarm bells. Vaccines for the vaccinia virus can protect against monkeypox, but these immunizations were stopped after smallpox was eradicated. There are, however, treatments available once the illness has taken hold. During the 2022 outbreak, most cases occurred among men who had sex with men, and there was a range of 7-10 days between exposure and the onset of symptoms. Three vaccines are currently used against the Monkeypox virus. Two of these vaccines were initially developed for smallpox, and the third is specifically designed for biological-terrorism protection. The first vaccine is an attenuated, nonreplicating smallpox vaccine that can also be used for immunocompromised individuals, marketed under different names in different regions. The second vaccine, ACAM2000, is a recombinant second-generation vaccine initially developed for smallpox. It is recommended for use in preventing monkeypox infection but is not recommended for individuals with certain health conditions or during pregnancy. The third vaccine, LC16m8, is a licensed attenuated smallpox vaccine designed to lack the B5R envelope-protein gene to reduce neurotoxicity. It generates neutralizing antibodies to multiple poxviruses and broad T-cell responses. The immune response takes 14 days after the second dose of the first two vaccines and 4 weeks after the ACAM2000 dose for maximal immunity development. The efficacy of these vaccines in the current outbreak of monkeypox is uncertain. Adverse events have been reported, and a next generation of safer and specific vaccines is needed. Although some experts claim that developing vaccines with a large spectrum of specificity can be advantageous, epitope-focused immunogens are often more effective in enhancing neutralization.

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.

Monkeypox: a global health emergency

Over the past 2 years, the world has faced the impactful Coronavirus Disease-2019 (COVID-19) pandemic, with a visible shift in economy, medicine, and beyond. As of recent times, the emergence of the monkeypox (mpox) virus infections and the growing number of infected cases have raised panic and fear among people, not only due to its resemblance to the now eradicated smallpox virus, but also because another potential pandemic could have catastrophic consequences, globally. However, studies of the smallpox virus performed in the past and wisdom gained from the COVID-19 pandemic are the two most helpful tools for humanity that can prevent major outbreaks of the mpox virus, thus warding off another pandemic. Because smallpox and mpox are part of the same virus genus, the Orthopoxvirus genus, the structure and pathogenesis, as well as the transmission of both these two viruses are highly similar. Because of these similarities, antivirals and vaccines approved and licensed in the past for the smallpox virus are effective and could successfully treat and prevent an mpox virus infection. This review discusses the main components that outline this current global health issue raised by the mpox virus, by presenting it as a whole, and integrating aspects such as its structure, pathogenesis, clinical aspects, prevention, and treatment options, and how this ongoing phenomenon is being globally approached.

An Ulcer by Any Other Name

The myriad presentations of ulcerative sexually transmitted infections, other than genital herpes and syphilis, challenge even the most astute clinician given the considerable overlap in clinical presentation and lack of widely available diagnostic resources, such as nucleic acid testing, to confirm the diagnosis. Even so, case prevalence is relatively low, and incidence of chancroid and granuloma inguinale are declining. These diseases still cause substantial morbidity and increased chance for HIV acquisition, and with the recent advent of mpox as a cause, it remains imperative to identify and treat accurately.

Perception of and Vaccine Readiness towards Mpox among Men Who Have Sex with Men Living with HIV in China: A Cross-Sectional Study

BACKGROUND

Men who have sex with men (MSM) living with HIV make up the majority of cases in the current Mpox outbreak. We aimed to investigate the perception of and vaccine readiness towards Mpox among MSM living with HIV in China.

METHODS

This cross-sectional online study was conducted from 10 August to 9 September 2022. Participants responded to survey questions about their socio-demographic information, HIV status, sexual behaviors, knowledge of Mpox, and attitudes towards Mpox vaccines.

RESULTS

A total of 577 MSM living with HIV participated in the study. A total of 37.6% expressed concerns about the Mpox epidemic in China, and 56.8% were willing to get the Mpox vaccine. Men who had > four sexual partners in the previous three months (aOR = 1.9 95% CI: 1.2-2.8 Ref: 0), had close contact with > four individuals in a day (3.1, 1.5-6.5 Ref: 0-3), were worried about the Mpox epidemic in China (1.6, 1.1-2.3 Ref: No), and believed that Mpox vaccines are safe (6.6, 2.7-16.4 Ref: No or not sure) and effective (1.9, 1.1-3.3 Ref: No) for people living with HIV were more likely to be willing to get the Mpox vaccine. MSM living with HIV with a high school education or below (0.5, 0.3-0.9 Ref: Postgraduate diploma), and sometimes (0.5, 0.3-0.8 Ref: Often), seldom, or never (0.5, 0.3-0.9 Ref: Often) followed news about Mpox were unwilling to get the Mpox vaccine.

CONCLUSION

The ongoing Mpox pandemic has not attracted widespread concerns among MSM living with HIV in China. Having more sexual partners and close contacts, worrying about the Mpox epidemic, and believing in the vaccine's safety and efficacy were predictors of their willingness to get the Mpox vaccine. Efforts should be made to raise awareness of the potential risk of Mpox in this at-risk population. Public health strategies should fully address predictors of vaccination willingness.

Safety and Efficacy of Post-Eradication Smallpox Vaccine as an Mpox Vaccine: A Systematic Review with Meta-Analysis

According to the World Health Organization, 83,339 laboratory-confirmed cases, including 72 deaths, of mpox (formerly known as monkeypox), have been reported from 110 locations globally as of 20 December 2022, making the disease a public health concern. Most of the cases (56,171, 67.4%) were reported from countries in North America. Limited data on vaccine effectiveness in the current mpox outbreak are available. However, the modified vaccinia virus (smallpox vaccine) has been predicted to prevent or reduce the severity of the mpox infection. The present study of systematic review and meta-analysis aimed to evaluate the modified vaccinia vaccine's safety and efficacy on mpox by using reported randomized clinical trials. Following guidelines from the Cochrane Collaboration and PRISMA, multiple databases including PubMed, PLOS ONE, Google Scholar, British Medical Journal, and the U. S. National Library of Medicine were searched. Out of 13,294 research articles initially identified, 187 were screened after removing duplicates. Following the inclusion and exclusion criteria, the meta-analysis included ten studies with 7430 patients. Three researchers independently assessed the risk of bias in the included study. The pooled results suggest that the vaccinia-exposed group had fewer side effects when compared to the vaccinia naïve group (odds ratio: 1.66; 95% CI: 1.07-2.57; p = 0.03). Overall, the modified vaccinia has proven safe and effective in both vaccinia naïve and previously exposed groups, with higher efficacy in the previously exposed groups.

A randomized phase 3 trial to assess the immunogenicity and safety of 3 consecutively produced lots of freeze-dried MVA-BN® vaccine in healthy adults

Since vaccination remains the only effective protection against orthopox virus-induced diseases such as smallpox or monkeypox, the strategic use and stockpiling of these vaccines remains of significant public health importance. The approved liquid-frozen formulation of Bavarian Nordic's Modified Vaccinia Ankara (MVA-BN) smallpox vaccine has specific cold-chain requirements, while the freeze-dried (FD) formulation of this vaccine provides more flexibility in terms of storage conditions and shelf life. In this randomized phase 3 trial, the immunogenicity and safety of 3 consecutively manufactured lots of the FD MVA-BN vaccine was evaluated. A total of 1129 healthy adults were randomized to 3 treatment groups (lots 1 to 3) and received 2 vaccinations 4 weeks apart. For both neutralizing and total antibodies, a robust increase of geometric mean titer (GMT) was observed across all lot groups 2 weeks following the second vaccination, comparable to published data. For the primary results, the ratios of the neutralizing antibody GMTs between the lot group pairs ranged from 0.936 to 1.115, with confidence ratios well within the pre-specified margin of equivalence. Results for total antibodies were similar. In addition, seroconversion rates were high across the 3 lots, ranging between 99.1 % and 99.7 %. No safety concerns were identified; particularly, no inflammatory cardiac disorders were detected. The most common local solicited adverse events (AEs) reported across lot groups were injection site pain (87.2%) and erythema (73.2%), while the most common general solicited adverse events were myalgia, fatigue, and headache in 40.6% to 45.5% of all participants, with no meaningful differences among the lot groups. No related serious AEs were reported. In conclusion, the data demonstrate consistent and robust immunogenicity and safety results with a freeze-dried formulation of MVA-BN. Clinical Trial Registry Number: NCT03699124.

A recombinant Modified Vaccinia virus Ankara expressing prME of tick-borne encephalitis virus affords mice full protection against TBEV infection

Introduction

Tick-borne encephalitis virus (TBEV) is an important human pathogen that can cause a serious disease involving the central nervous system (tick-borne encephalitis, TBE). Although approved inactivated vaccines are available, the number of TBE cases is rising, and breakthrough infections in fully vaccinated subjects have been reported in recent years.

Methods

In the present study, we generated and characterized a recombinant Modified Vaccinia virus Ankara (MVA) for the delivery of the pre-membrane (prM) and envelope (E) proteins of TBEV (MVA-prME).

Results

MVA-prME was tested in mice in comparison with a licensed vaccine FSME-IMMUN® and proved to be highly immunogenic and afforded full protection against challenge infection with TBEV.

Discussion

Our data indicate that MVA-prME holds promise as an improved next-generation vaccine for the prevention of TBE.

Smallpox, Monkeypox and Other Human Orthopoxvirus Infections

Considering that vaccination against smallpox with live vaccinia virus led to serious adverse effects in some cases, the WHO, after declaration of the global eradication of smallpox in 1980, strongly recommended to discontinue the vaccination in all countries. This led to the loss of immunity against not only smallpox but also other zoonotic orthopoxvirus infections in humans over the past years. An increasing number of human infections with zoonotic orthopoxviruses and, first of all, monkeypox, force us to reconsider a possible re-emergence of smallpox or a similar disease as a result of natural evolution of these viruses. The review contains a brief analysis of the results of studies on genomic organization and evolution of human pathogenic orthopoxviruses, development of modern methods for diagnosis, vaccination, and chemotherapy of smallpox, monkeypox, and other zoonotic human orthopoxvirus infections.

The land-scape of immune response to monkeypox virus

Human monkeypox is a viral zoonotic smallpox-like disease caused by the monkeypox virus (MPXV) and has become the greatest public health threat in the genus Orthopoxvirus after smallpox was eradicated. The host immune response to MPXV plays an essential role in disease pathogenesis and clinical manifestations. MPXV infection leads to skin lesions with the genital area as the main feature in the current outbreak and triggers a strong immune response that results in sepsis, deep tissue abscess, severe respiratory disease, and injuries to multiple immune organs. Emerging evidence shows that the immunopathogenesis of MPXV infection is closely associated with impaired NK-cell function, lymphopenia, immune evasion, increased antibodies, increased blood monocytes and granulocytes, cytokine storm, inhibition of the host complement system, and antibody-dependent enhancement. In this overview, we discuss the immunopathology and immunopathogenesis of monkeypox to aid the development of novel immunotherapeutic strategies against monkeypox.

Psychological Antecedents of Healthcare Workers towards Monkeypox Vaccination in Nigeria

The ongoing monkeypox (MPX) outbreak has been declared a public health emergency of international concern. People in close contact with active MPX cases, including healthcare workers (HCWs), are at higher risk of virus acquisition since the MPX virus can be transmitted by skin contact or respiratory secretions. In this study, we aimed to assess the psychological antecedents of MPX vaccination among Nigerian HCWs using the 5C scale. We used an anonymous online cross-sectional survey to recruit potential participants using snowball sampling. The questionnaire aimed to assess the geo/socioeconomic features and the 5C psychological antecedents of vaccine acceptance (confidence, complacency, constraints, calculation, and collective responsibility). A total of 389 responses were included, with a median age of 37 years (IQR: 28−48), 55.5% males, and 60.7% married participants. Among the studied Nigerian HCWs, only 31.1% showed confidence in MPX vaccination, 58.4% expressed complacency towards vaccination, 63.8% perceived constraints towards MPX vaccination, 27.2% calculated the benefits and risks of vaccination, and 39.2% agreed to receive MPX vaccination to protect others. The determinants of MPX vaccine confidence were being single (OR = 5.07, 95% CI: 1.26−20.34, p = 0.022), a higher education level (with pre-college/high school as a reference, professional/technical: OR = 4.12, 95% CI: 1.57−10.73, p = 0.004, undergraduate: OR = 2.94, 95% CI: 1.32−6.55, p = 0.008, and postgraduate degree (OR = 3.48, 95% CI: 1.51−8.04, p = 0.003), and absence of chronic disease (OR = 2.57, 95% CI: 1.27−5.22, p = 0.009). The significant complacency predictors were having a middle-income (OR = 0.53, 95% CI: 0.33−0.89, p = 0.008), having a bachelor’s degree (OR = 2.37, 95% CI: 1.10−5.11, p = 0.027), and knowledge of someone who died due to MPX (OR = 0.20, 95% CI: 0.05−0.93, p = 0.040). Income was associated with perceived vaccination constraints (OR = 0.62, 95% CI: 0.39−0.99, p = 0.046). Participants aged 46−60 years had decreased odds in the calculation domain (OR = 0.52, 95% CI: 0.27−0.98, p = 0.044). Middle-income and bachelor degree/postgraduate education significantly influenced the collective responsibility domain (OR = 2.10, 95% CI: 1.19−3.69, p = 0.010; OR = 4.17, 95% CI: 1.85−9.38, p < 0.001; and OR = 3.45, 95% CI: 1.50−7.90, p = 0.003, respectively). An investigation of the 5C pattern-based psychological antecedents of MPX vaccination in a sample of Nigerian HCWs revealed low levels of vaccine confidence and collective responsibility with high levels of constraints and complacency. These psychological factors are recommended to be considered in any efforts aiming to promote MPX vaccination needed in a country where MPX is endemic.

Human Monkeypox Virus Infection in the Immediate Period After Receiving Modified Vaccinia Ankara Vaccine

This study uses electronic medical record data to describe monkeypox infections after a single dose of Modified Vaccinia Ankara-Bavarian Nordic vaccine, a live, nonreplicating vaccine indicated for prevention of smallpox and monkeypox infection in adults.

Monkeypox: epidemiology, pathogenesis, treatment and prevention

Monkeypox is a zoonotic disease that was once endemic in west and central Africa caused by monkeypox virus. However, cases recently have been confirmed in many nonendemic countries outside of Africa. WHO declared the ongoing monkeypox outbreak to be a public health emergency of international concern on July 23, 2022, in the context of the COVID-19 pandemic. The rapidly increasing number of confirmed cases could pose a threat to the international community. Here, we review the epidemiology of monkeypox, monkeypox virus reservoirs, novel transmission patterns, mutations and mechanisms of viral infection, clinical characteristics, laboratory diagnosis and treatment measures. In addition, strategies for the prevention, such as vaccination of smallpox vaccine, is also included. Current epidemiological data indicate that high frequency of human-to-human transmission could lead to further outbreaks, especially among men who have sex with men. The development of antiviral drugs and vaccines against monkeypox virus is urgently needed, despite some therapeutic effects of currently used drugs in the clinic. We provide useful information to improve the understanding of monkeypox virus and give guidance for the government and relative agency to prevent and control the further spread of monkeypox virus.

Monkeypox Virus Outbreak 2022: Key Epidemiologic, Clinical, Diagnostic, and Prevention Considerations

ABSTRACT

Monkeypox is a zoonotic infection that manifests as dermatologic lesions that may be painful or pruritic and can appear on the face, trunk, extremities, genitals, and mucosal surfaces. In 2022, cases of monkeypox increased exponentially and it was declared a public health emergency by the World Health Organization and the U.S. Department of Health and Human Services. Unlike previous monkeypox outbreaks, the current situation has disproportionately affected men who have sex with men and seems to be associated with lower mortality. Options for treatment and prevention are limited. The distribution and availability of vaccines and antivirals has posed challenges for patients, clinicians, and public health systems. Early recognition and management of persons with monkeypox is critical in controlling the spread of this infection. This article reviews key features of monkeypox and highlights current recommendations for clinical management, prevention, and considerations for persons with HIV. Implications for public health and nursing are discussed.

Development of Modified Vaccinia Virus Ankara-Based Vaccines: Advantages and Applications

Modified vaccinia virus Ankara (MVA) is a promising viral vector for vaccine development. MVA is well studied and has been widely used for vaccination against smallpox in Germany. This review describes the history of the origin of the virus and its properties as a vaccine, including a high safety profile. In recent years, MVA has found its place as a vector for the creation of vaccines against various diseases. To date, a large number of vaccine candidates based on the MVA vector have already been developed, many of which have been tested in preclinical and clinical studies. We discuss data on the immunogenicity and efficacy of some of these vaccines.

Preventing the Next Pandemic: Is Live Vaccine Efficacious against Monkeypox, or Is There a Need for Killed Virus and mRNA Vaccines?

(1) Background: The monkeypox virus (MPV) is a double-stranded DNA virus belonging to the Poxviridae family, Chordopoxvirinae subfamily, and Orthopoxvirus genus. It was called monkeypox because it was first discovered in monkeys, in a Danish laboratory, in 1958. However, the actual reservoir for MPV is still unknown. (2) Methods and Results: We have reviewed the existing literature on the options for Monkeypox virus. There are three available vaccines for orthopoxviruses—ACAM2000, JYNNEOS, and LC16—with the first being a replicating vaccine and the latter being non- or minimally replicating. (3) Conclusions: Smallpox vaccinations previously provided coincidental immunity to MPV. ACAM2000 (a live-attenuated replicating vaccine) and JYNNEOS (a live-attenuated, nonreplicating vaccine) are two US FDA-approved vaccines that can prevent monkeypox. However, ACAM2000 may cause serious side effects, including cardiac problems, whereas JYNNEOS is associated with fewer complications. The recent outbreaks across the globe have once again highlighted the need for constant monitoring and the development of novel prophylactic and therapeutic modalities. Based on available data, there is still a need to develop an effective and safe new generation of vaccines specific for monkeypox that are killed or developed into a mRNA vaccine before monkeypox is declared a pandemic.

Monkeypox and Its Possible Sexual Transmission: Where Are We Now with Its Evidence?

Monkeypox is a rare disease but is increasing in incidence in different countries since the first case was diagnosed in the UK by the United Kingdom (UK) Health Security Agency on 6 May 2022. As of 9 August, almost 32,000 cases have been identified in 89 countries. In endemic areas, the monkeypox virus (MPXV) is commonly transmitted through zoonosis, while in non-endemic regions, it is spread through human-to-human transmission. Symptoms can include flu-like symptoms, rash, or sores on the hands, feet, genitalia, or anus. In addition, people who did not take the smallpox vaccine were more likely to be infected than others. The exact pathogenesis and mechanisms are still unclear; however, most identified cases are reported in men who have sex with other men (MSM). According to the CDC, transmission can happen with any sexual or non-sexual contact with the infected person. However, a recent pooled meta-analysis reported that sexual contact is involved in more than 91% of cases. Moreover, it is the first time that semen analysis for many patients has shown positive monkeypox virus DNA. Therefore, in this review, we will describe transmission methods for MPXV while focusing mainly on potential sexual transmission and associated sexually transmitted infections. We will also highlight the preventive measures that can limit the spread of the diseases in this regard.

Monkeypox: A New Threat?

The global vaccination programme against smallpox led to its successful eradication and averted millions of deaths. Monkeypox virus (MPXV) is a close relative of the Variola (smallpox) virus. Due to antigenic similarity, smallpox vaccines cross-protect against MPXV. However, over 70% of people living today were never vaccinated against smallpox. Symptoms of monkeypox (MPX) include fever, head- and muscle ache, lymphadenopathy and a characteristic rash that develops into papules, vesicles and pustules which eventually scab over and heal. MPX is less often fatal (case fatality rates range from <1% to up to 11%) than smallpox (up to 30%). MPXV is endemic in sub-Saharan Africa, infecting wild animals and causing zoonotic outbreaks. Exotic animal trade and international travel, combined with the increasing susceptibility of the human population due to halted vaccination, facilitated the spread of MPXV to new areas. The ongoing outbreak, with >10,000 cases in >50 countries between May and July 2022, shows that MPXV can significantly spread between people and may thus become a serious threat to public health with global consequences. Here, we summarize the current knowledge about this re-emerging virus, discuss available strategies to limit its spread and pathogenicity and evaluate its risk to the human population.

Intranasal inoculation of an MVA-based vaccine induces IgA and protects the respiratory tract of hACE2 mice from SARS-CoV-2 infection

Despite the ability of current vaccines to significantly prevent severe disease due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), vaccinated individuals are still susceptible to infection and contribute to the spread of the virus. The present study demonstrates that a live, replication-deficient recombinant virus vaccine induces greater immunity and a greater level of protection in the respiratory tract of susceptible transgenic mice when inoculated intranasally compared with intramuscularly. Second-generation vaccines administered via the upper respiratory tract have the potential to limit the spread of SARS-CoV-2 more effectively than current vaccines.

Current vaccines have greatly diminished the severity of the COVID-19 pandemic, even though they do not entirely prevent infection and transmission, likely due to insufficient immunity in the upper respiratory tract. Here, we compare intramuscular and intranasal administration of a live, replication-deficient modified vaccinia virus Ankara (MVA)–based Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike (S) vaccine to raise protective immune responses in the K18-hACE2 mouse model. Using a recombinant MVA expressing firefly luciferase for tracking, live imaging revealed luminescence of the respiratory tract of mice within 6 h and persisting for 3 d following intranasal inoculation, whereas luminescence remained at the site of intramuscular vaccination. Intramuscular vaccination induced S-binding–Immunoglobulin G (IgG) and neutralizing antibodies in the lungs, whereas intranasal vaccination also induced Immunoglobulin A (IgA) and higher levels of antigen-specific CD3⁺CD8⁺IFN-γ⁺ T cells. Similarly, IgG and neutralizing antibodies were present in the blood of mice immunized intranasally and intramuscularly, but IgA was detected only after intranasal inoculation. Intranasal boosting increased IgA after intranasal or intramuscular priming. While intramuscular vaccination prevented morbidity and cleared SARS-CoV-2 from the respiratory tract within several days after challenge, intranasal vaccination was more effective as neither infectious virus nor viral messenger (m)RNAs were detected in the nasal turbinates or lungs as early as 2 d after challenge, indicating prevention or rapid elimination of SARS-CoV-2 infection. Additionally, we determined that neutralizing antibody persisted for more than 6 mo and that serum induced to the Wuhan S protein neutralized pseudoviruses expressing the S proteins of variants, although with less potency, particularly for Beta and Omicron.

Protective CD8+ T Cell Response Induced by Modified Vaccinia Virus Ankara Delivering Ebola Virus Nucleoprotein

The urgent need for vaccines against Ebola virus (EBOV) was underscored by the large outbreak in West Africa (2014–2016). Since then, several promising vaccine candidates have been tested in pre-clinical and clinical studies. As a result, two vaccines were approved for human use in 2019/2020, of which one includes a heterologous adenovirus/Modified Vaccinia virus Ankara (MVA) prime-boost regimen. Here, we tested new vaccine candidates based on the recombinant MVA vector, encoding the EBOV nucleoprotein (MVA-EBOV-NP) or glycoprotein (MVA-EBOV-GP) for their efficacy after homologous prime-boost immunization in mice. Our aim was to investigate the role of each antigen in terms of efficacy and correlates of protection. Sera of mice vaccinated with MVA-EBOV-GP were virus-neutralizing and MVA-EBOV-NP immunization readily elicited interferon-γ-producing NP-specific CD8+ T cells. While mock-vaccinated mice succumbed to EBOV infection, all vaccinated mice survived and showed drastically decreased viral loads in sera and organs. In addition, MVA-EBOV-NP vaccinated mice became susceptible to lethal EBOV infection after depletion of CD8+ T cells prior to challenge. This study highlights the potential of MVA-based vaccines to elicit humoral immune responses as well as a strong and protective CD8+ T cell response and contributes to understanding the possible underlying mechanisms.

The Brighton Collaboration standardized template for collection of key information for risk/benefit assessment of a Modified Vaccinia Ankara (MVA) vaccine platform

The Brighton Collaboration Viral Vector Vaccines Safety Working Group (V3SWG) was formed to evaluate the safety and characteristics of live, recombinant viral vector vaccines. The Modified Vaccinia Ankara (MVA) vector system is being explored as a platform for development of multiple vaccines. This paper reviews the molecular and biological features specifically of the MVA-BN vector system, followed by a template with details on the safety and characteristics of an MVA-BN based vaccine against Zaire ebolavirus and other filovirus strains. The MVA-BN-Filo vaccine is based on a live, highly attenuated poxviral vector incapable of replicating in human cells and encodes glycoproteins of Ebola virus Zaire, Sudan virus and Marburg virus and the nucleoprotein of the Thai Forest virus. This vaccine has been approved in the European Union in July 2020 as part of a heterologous Ebola vaccination regimen. The MVA-BN vector is attenuated following over 500 serial passages in eggs, showing restricted host tropism and incompetence to replicate in human cells. MVA has six major deletions and other mutations of genes outside these deletions, which all contribute to the replication deficiency in human and other mammalian cells. Attenuation of MVA-BN was demonstrated by safe administration in immunocompromised mice and non-human primates. In multiple clinical trials with the MVA-BN backbone, more than 7800 participants have been vaccinated, demonstrating a safety profile consistent with other licensed, modern vaccines. MVA-BN has been approved as smallpox vaccine in Europe and Canada in 2013, and as smallpox and monkeypox vaccine in the US in 2019. No signal for inflammatory cardiac disorders was identified throughout the MVA-BN development program. This is in sharp contrast to the older, replicating vaccinia smallpox vaccines, which have a known risk for myocarditis and/or pericarditis in up to 1 in 200 vaccinees. MVA-BN-Filo as part of a heterologous Ebola vaccination regimen (Ad26.ZEBOV/MVA-BN-Filo) has undergone clinical testing including Phase III in West Africa and is currently in use in large scale vaccination studies in Central African countries. This paper provides a comprehensive picture of the MVA-BN vector, which has reached regulatory approvals, both as MVA-BN backbone for smallpox/monkeypox, as well as for the MVA-BN-Filo construct as part of an Ebola vaccination regimen, and therefore aims to provide solutions to prevent disease from high-consequence human pathogens.

[We should be prepared to smallpox re-emergence.]

The review contains a brief analysis of the results of investigations conducted during 40 years after smallpox eradication and directed to study genomic organization and evolution of variola virus (VARV) and development of modern diagnostics, vaccines and chemotherapies of smallpox and other zoonotic orthopoxviral infections of humans. Taking into account that smallpox vaccination in several cases had adverse side effects, WHO recommended ceasing this vaccination after 1980 in all countries of the world. The result of this decision is that the mankind lost the collective immunity not only to smallpox, but also to other zoonotic orthopoxvirus infections. The ever more frequently recorded human cases of zoonotic orthopoxvirus infections force to renew consideration of the problem of possible smallpox reemergence resulting from natural evolution of these viruses. Analysis of the available archive data on smallpox epidemics, the history of ancient civilizations, and the newest data on the evolutionary relationship of orthopoxviruses has allowed us to hypothesize that VARV could have repeatedly reemerged via evolutionary changes in a zoonotic ancestor virus and then disappeared because of insufficient population size of isolated ancient civilizations. Only the historically last smallpox pandemic continued for a long time and was contained and stopped in the 20th century thanks to the joint efforts of medics and scientists from many countries under the aegis of WHO. Thus, there is no fundamental prohibition on potential reemergence of smallpox or a similar human disease in future in the course of natural evolution of the currently existing zoonotic orthopoxviruses. Correspondingly, it is of the utmost importance to develop and widely adopt state-of-the-art methods for efficient and rapid species-specific diagnosis of all orthopoxvirus species pathogenic for humans, VARV included. It is also most important to develop new safe methods for prevention and therapy of human orthopoxvirus infections.