Abstract
The resurgence of monkeypox (mpox), driven by Clade IIb of the monkeypox virus (MPXV), has intensified global concerns about its transmission, treatment, and prevention. Mpox, a zoonotic orthopoxvirus and is primarily transmitted through close contact with infected individuals, contaminated surfaces, or respiratory droplets. Historically, the virus has been divided into two clades: Clade I, endemic to Central Africa and characterized by higher fatality rates, and Clade II, linked to milder disease in West Africa. The unprecedented global spread of Clade IIb Mpox in 2022, affecting over 99,000 individuals across 118 countries, underscored the potential for widespread transmission beyond endemic regions. This review provides a detailed examination of the transmission dynamics of mpox, current treatments, innovations, and global health challenges. Current treatment strategies primarily involve supportive care, with advanced therapeutics such as tecovirimat, cidofovir, and brincidofovir reserved for severe cases. While these antivirals show promise, their clinical efficacy and safety remain inadequately substantiated, creating a pressing need for rigorous trials. Preventive measures, including vaccination and postexposure prophylaxis, remain pivotal in mitigating disease spread, yet face barriers such as limited supply, accessibility, and vaccine hesitancy. Emerging therapeutic innovations, such as monoclonal antibodies, gene-editing technologies, and RNA-based therapies, offer hope for addressing these gaps. These novel approaches aim to enhance treatment specificity, minimize off-target effects, and reduce the risk of resistance. However, their successful integration into clinical practice demands robust validation through preclinical and clinical research. In addressing the challenges ahead, this review underscores the critical importance of global collaboration to strengthen epidemiological surveillance, accelerate drug development, and optimize prevention strategies. The emergence of drug-resistant strains, the persistence of mpox in vulnerable populations, and the potential for future outbreaks necessitate sustained investment in research and public health infrastructure. By integrating innovative therapeutic approaches, effective preventive measures, and comprehensive outbreak management strategies, the global health community can better address the ongoing threat of mpox and prepare for future public health challenges.
Introduction
Mpox, previously known as monkeypox, is a zoonotic viral disease caused by the monkeypox virus (MPXV), which belongs to the orthopoxvirus genus. The virus was first identified in 1958 in a colony of research monkeys, with the first human case reported in 1970 in the Democratic Republic of Congo (DRC). 1 Clinically, mpox is typically characterized by fever, rash, and swollen lymph nodes, which have remained consistent features up to 2022. However, during the 2022 outbreak, a shift in the clinical presentation was observed, with the rash more frequently appearing in the genital and perianal regions rather than on the face and hands, which had been more typical in previous outbreaks. This change in the distribution of the rash suggests potential alterations in the virus’s behavior or transmission dynamics during the 2022 epidemic. 2 MPXV is a double-stranded DNA virus with a genome size of approximately 200 kilobases, encoding 191 proteins. It is classified into two primary genetic clades: Clade I, which is predominantly found in Central Africa and has been associated with outbreaks characterized by higher fatality rates between 1981 and 2017, and Clade II, which is endemic to West Africa and generally causes a milder form of the disease.3,4 In recent years, mpox has attracted increased international attention due to outbreaks in non-endemic regions. 5
The 2022 mpox outbreak marked a notable shift in the disease’s epidemiological patterns, with the virus spreading outstripping its conventional endemic regions in Central and West Africa to a wide range of countries all over Europe, the Americas, and other regions. The peak of the Clade II MPXV escalation outside of Africa occurred during the summer of 2022, prompting the “World Health Organization (WHO) to declare a Public Health Emergency of International Concern (PHEIC)” on July 23, 2022. This declaration was lifted on May 10, 2023, following a decline in cases. However, a resurgence of Clade I MPXV infections in Central Africa led to a second PHEIC declaration by the WHO on August 14, 2024. 6 Furthermore, in November 2024, the first reported case of Clade I mpox in the United States was noted in an individual who had traveled from an affected region, 7 though no further cases have been reported. Meanwhile, Clade II mpox is still active at relatively low levels. 8 As of August 2024, over 120 countries have documented more than 100,000 confirmed cases, with over 220 deaths associated with the outbreak. The outbreak was primarily driven by Clade IIb, which is endemic to West Africa, though Clades Ia and Ib have also been identified, with significant transmission occurring in regions such as the DRC and Sudan. While mpox has traditionally affected small mammals such as squirrels and monkeys, the recent global spread highlights the complex dynamics of human-to-human transmission, which has been especially prominent among men who have sex with men (MSM) and those with concurrent sexually transmitted infections. This shift in transmission patterns has further emphasized the importance of early detection, as the clinical presentation of mpox can overlap with other common infectious diseases, including chickenpox, syphilis, and herpes. 9 Moreover, as the mpox continues to spread globally, substantial challenges in treatment persist, primarily due to the lack of specific antiviral therapies, limited clinical data, and the evolving nature of the virus. 10 Although several therapeutic agents, including “tecovirimat, cidofovir, and brincidofovir,” are being utilized, there remains a notable gap in conclusive evidence regarding their efficacy and safety in humans.11–13 This gap is compounded by the absence of “U.S. Food and Drug Administration (FDA)” approved medications specifically for Mpox, highlighting the urgent need for continued research and development. 10 Addressing these challenges requires a comprehensive approach, including robust clinical trials, improved epidemiological surveillance, and the exploration of novel therapeutic strategies. In light of the increasing concerns surrounding the recent mpox outbreak, this review provides a comprehensive discussion of the virus transmission dynamics, current treatment strategies, emerging therapeutic innovations, preventive measures, and the challenges that lie ahead in addressing mpox.
Transmission dynamics of Mpox virus
Mpox is primarily transmitted through close personal contact, with direct skin-to-skin contact with an infected person’s rash or scabs being the main route. The virus can also spread through contact with bodily fluids such as saliva, respiratory secretions, and lesions in the genital, anal, or rectal areas. Pregnant individuals may transmit the virus to their fetus or newborn during or after birth. Intimate contact, including oral, anal, or vaginal sex, and touching of genital or anal areas, significantly increases transmission risk. In addition, contaminated objects and surfaces such as clothing, bedding, towels, and sex toys can serve as vehicles for virus spread if not disinfected properly. Mpox is zoonotic, with potential transmission from infected animals, especially in endemic regions such as Central and West Africa. Activities like hunting, trapping, or handling wild animals increase the risk of infection. While the risk from pets is lower, transmission can still occur through close contact with infected animals. To minimize transmission, individuals with mpox should avoid contact with animals, including pets.14–16 The primary reservoir of MPXV is believed to be arboreal rodents, particularly the Funisciurus anerythrus squirrel, and initial human cases are often linked to direct contact with infected animals or consumption of undercooked meat17,18 (Figure 1).
Transmission of mpox.
Although the virus can be present in respiratory droplets, its transmission through the air appears to be limited. Studies have indicated that respiratory droplets may harbor the virus, and transmission has occasionally been observed between animals housed in close proximity for extended periods in laboratory settings. However, data from real-world outbreaks suggest that human-to-human respiratory transmission is unlikely to be a major route of infection. Accordingly, the “Centers for Disease Control and Prevention (CDC)” recommends that individuals with mpox wear a mask when in the presence of others, particularly when receiving medical care. Healthcare workers and caregivers are advised to use appropriate personal protective equipment (PPE) to alleviate the risk of transmission. 16 While replication-competent MPXV has been identified in the respiratory tract, there is no substantial evidence indicating that significant human outbreaks occur solely through shared airspace without close physical contact. 18 A case study tracing 113 infections associated with 221 commercial flights identified no subsequent mpox cases, further underscoring the limited role of airborne transmission in typical settings. 19 Human-to-human transmission primarily occurs via direct and extended exposure to lesions or bodily fluids of infected individuals. 19 Emerging evidence also suggests the possibility of pre-symptomatic and asymptomatic transmission, which may contribute to disease spread.20–22 Occupational exposure to MPXV, including laboratory-acquired infections, is rare and typically associated with needle-stick injuries, direct handling of MPXV-containing specimens, or inhalation of aerosols generated during laboratory procedures. Infection occurs when the virus gains entry into the host via skin breaches or mucosal surfaces, such as oral, anogenital, or ocular tissues. Following entry, MPXV targets local immune cells and lymph nodes, where it undergoes initial replication before spreading through the lymphatic system and bloodstream to infect other organs. 23
Nosocomial transmission, while rare, has been documented in African healthcare settings but not in hospitalized patients within the United States. 24 A review during the 2022 global outbreak identified only 10 cases of healthcare-associated transmission, primarily due to sharp object injuries. 25 Notably, data from a Colorado healthcare facility indicated no cases of MPXV transmission among 313 clinicians exposed to infected patients, despite suboptimal use of PPE and limited postexposure prophylaxis vaccination. 26 Individuals suspected of having mpox should be placed in isolation in private rooms. Disinfection should be carried out using hospital-grade disinfectants approved by the “Environmental Protection Agency (EPA)” for emerging viral pathogens. Airborne isolation is not necessary for mpox patients. Non-hospitalized individuals with confirmed or suspected MPXV infection should isolate at home until all lesions have healed and new skin has formed. 6 However, regarding environmental transmission, there is currently no evidence to suggest a direct link between mpox and water exposure in recreational settings such as pools, hot tubs, or splash pads. The virus is inactivated in water treated with chlorine at concentrations recommended by the CDC for disinfection in these venues, which are also mandated by local health authorities. 16
Unlike earlier outbreaks, which were predominantly associated with contact with infected animals or travel to endemic regions, the recent mpox epidemic represents the largest outbreak reported outside Africa.27–29 In this outbreak, most cases are linked to sexual contact rather than traditional zoonotic or travel-related exposures. A study revealed that 98% of the cases involved MSM or bisexual males, with 41% of these individuals coinfected with HIV. The majority of lesions, approximately 73%, were located in the anal and genital areas.30,31 The virus has an incubation period of approximately 7 to 14 days, with manifestations lasting between 14 and 21 days.32,33 This extended incubation phase presents diagnostic challenges, possible delay in medical intervention, and contributing to further disease spread.34,35 Given the evolving transmission patterns and the increasing number of affected populations, it is essential to explore the current therapeutic strategies aimed at mitigating disease severity and controlling outbreaks.
Current therapeutic approaches
Currently, no treatments have been formally authorized by the FDA for mpox; numerous antiviral medications designed for other orthopoxviruses have been employed to treat severe mpox infections. Most patients, especially those who do not exhibit severe disease or have risk factors for severe disease, such as significant immunocompromise, typically recover with supportive care and pain management. However, severe manifestations of mpox have been observed in some patients, including ocular infections, neurological complications, myopericarditis, and mucosal lesion-related issues such as in the oral, rectal, genital, and urethral areas. In addition, patients with severe immunocompromise, particularly those with advanced HIV infection, as well as those with certain skin conditions like eczema, are at increased risk of life-threatening excessive viral spread. 36
Supportive care
Supportive care is pivotal in managing complications associated with mpox, with a primary focus on symptom control, infection prevention, and psychosocial support, all of which are essential for improving patient outcomes and minimizing transmission risks. Firstly, the effective management of symptoms is essential in treating mpox, particularly in alleviating the discomfort associated with skin and mucosal lesions, as well as systemic fever. Analgesics and antipyretics are commonly utilized to manage these symptoms, providing necessary relief for patients. The CDC provides specific guidelines for supportive care and pain management, which recommend oral medications such as “acetaminophen or nonsteroidal anti-inflammatory drugs for pain control.” For cases involving more severe pain, gabapentinoids or short-term opioid therapies may be prescribed. In addition, stool softeners are advised to mitigate painful bowel movements, often associated with proctitis. Topical treatments, including sitz baths or lidocaine gels for proctitis and saltwater or viscous lidocaine gargles for pharyngitis, are also effective in reducing discomfort. These strategies are critical in managing the painful symptoms of mpox, improving patient comfort and outcomes.4,6,37,38
Moreover, rigorous infection control measures, including strict isolation protocols and the use of PPE, are crucial for preventing hospital-acquired infections. Nurses are instrumental in implementing these protocols and in educating both patients and healthcare staff on proper practices. In addition, appropriate wound care is vital for preventing secondary bacterial infections and involves regular cleaning and dressing of skin lesions. 37 In cases where bacterial superinfection of mpox lesions is suspected, the use of topical or systemic antibiotics, appropriate for treating skin and soft tissue infections, is recommended. 6
Finally, the psychosocial support is critical because the infectious nature of mpox often induces significant anxiety and fear among patients. Delivering empathetic care and maintaining communication with patients’ families are vital components of supportive care. 37 An interdisciplinary team approach, involving specialists such as dermatologists and infectious disease experts, is essential for the comprehensive management of complex cases, promoting timely and effective interventions 39 (Table 1).
Supportive care.
Medical treatment
Antiviral medications are pivotal in the management of mpox, caused by the MPXV, though their efficacy remains unvalidated in randomized or nonrandomized trials. 4 Tecovirimat, initially approved for smallpox under the FDA Animal Efficacy Rule based on orthopoxvirus similarity, is considered a potential therapeutic option. 40 Tecovirimat, the first antiviral approved for orthopoxvirus infections, is available in oral and intravenous formulations.13,14,41 While in vitro studies suggest that cidofovir and brincidofovir are effective against poxviruses, the clinical application of brincidofovir has been limited due to drug-related adverse effects, as reported in recent cases. 14 These antivirals provide a rational approach to treating mpox, but further clinical studies are required to establish their safety and efficacy (Table 2).
Antivirals used in the management of Mpox.
Mpox, monkeypox.
Tecovirimat
Tecovirimat, has also been utilized as an emergency investigational drug to manage complications from the smallpox vaccine. 14 It is an antiviral agent that inhibits the p37 protein, a critical component in the formation and maturation of the orthopoxvirus envelope. The p37 protein, encoded by the F13 gene, is essential for the final steps of virus maturation. Tecovirimat interferes with the interaction between the p37 protein and host cell factors, namely Rab9 guanosine triphosphatase and TIP47. This disruption prevents the proper wrapping of the viral membrane around the intracellular mature virus (IMV), thus inhibiting the formation of the intracellular enveloped virus (IEV). The IEV is necessary for virion release and viral dissemination from the site of infection. By targeting this specific step in the orthopoxvirus life cycle, tecovirimat prevents the maturation and spread of the virus. The p37 protein is highly conserved among orthopoxviruses, including vaccinia, variola, cowpox, and MPXVs, providing tecovirimat with broad-spectrum antiviral activity within this virus family. Its mechanism is highly selective to orthopoxviruses and does not affect other virus families, such as herpesviruses (Figure 2).6,14,42
Mechanism of antivirals in the treatment of mpox.
In the United States, over 7000 individuals with mpox have been treated with tecovirimat under the “Expanded Access for an Investigational New Drug (EA-IND) protocol.” Available safety data suggest that the drug is generally well-tolerated, with reported adverse effects being mild. 43 Observational studies evaluating the effectiveness of tecovirimat have provided inconsistent results.44–47 Recently, a placebo-controlled randomized trial assessing the safety and efficacy of oral tecovirimat for mpox treatment was conducted. Preliminary findings from this study, which included 597 children and adults infected with clade I MPXV in the DRC, indicated that tecovirimat did not significantly reduce the duration of mpox skin lesions. 48 However, in the US, tecovirimat is accessible through the “Study of Tecovirimat for Human Mpox Virus (STOMP)” clinical trial and via the CDC’s EA-IND protocol for patients with severe disease or at increased risk of severe outcomes. Moreover, interim data analysis from the STOMP trial indicated that the antiviral drug tecovirimat did not significantly reduce the time to lesion resolution or alleviate pain in adults with mild-to-moderate intensity clade II mpox who were at low risk of progressing to severe disease. However, no safety concerns were identified in association with tecovirimat administration during the trial. 48 The most commonly reported adverse drug reactions include headache, abdominal discomfort, dry mouth, nausea, vomiting, and hypersensitivity reactions.49,50 Furthermore, resistance to tecovirimat, characterized by reduced drug activity, has been documented, particularly among immunocompromised patients receiving extended treatment courses. This resistance is associated with mutations in the F13L gene of the MXPV, which encodes the p37 protein essential for viral maturation and spread. Cases of transmitted drug resistance have also been reported.51–53
Cidofovir and brincidofovir
Cidofovir and brincidofovir demonstrate potential efficacy against MPXV clades I, IIa, and IIb in vitro, particularly can limit clade IIb replication. Both drugs exhibit broad-spectrum antiviral activity against poxviruses, including MPXV, as evidenced in various animal studies. Although not specifically approved for monkeypox, they are recommended for compassionate use in severe cases, leveraging their FDA approval for smallpox treatment.
Cidofovir has demonstrated robust antiviral activity against MPXV clade IIa and IIb strains in preclinical studies, significantly reducing viral replication in the respiratory tract when administered systemically. 54 Its mechanism of action involves inhibition of DNA synthesis by competing with deoxycytidine triphosphate (dCTP) at the viral DNA polymerase binding site, effectively halting viral replication. 55 Moreover, brincidofovir (prodrug of cidofovir), a lipophilic derivative of cidofovir, has also exhibited antiviral activity in animal models, though its efficacy is influenced by the timing of administration (Figure 2). Studies in a prairie dog model revealed that earlier initiation of treatment is associated with improved survival rates. 56 Similar to cidofovir, brincidofovir inhibits viral DNA synthesis, providing a structural basis for its antiviral action. 55 Oral administration of brincidofovir has demonstrated efficacy in limiting viral replication in vivo during a nonlethal challenge with MPXV clade IIb. In addition, brincidofovir therapy offers partial protection and significantly reduces viral burden in the context of a lethal MPXV clade IIa challenge. 54 However, brincidofovir’s use is limited by its adverse event profile and a paucity of clinical trials evaluating its efficacy against MPXV in humans. 57 Cidofovir and brincidofovir are currently employed off-label for treating MPXV, supported by preclinical evidence. However, the lack of robust randomized controlled trials (RCTs) hinders definitive conclusions about their clinical efficacy and safety. 57 Moreover, cidofovir is commonly linked to adverse effects such as neutropenia, reduced intraocular pressure, and nephrotoxicity. Brincidofovir, its lipid-conjugated analogue, with neutropenia, reduced intraocular pressure, and nephrotoxicity being the most frequently reported reactions.49,50 Challenges such as the potential for drug resistance and viral evolution underscore the necessity for innovative therapeutic strategies, including combination regimens. 58
Vaccinia immune globulin intravenous
“Vaccinia immune globulin Intravenous (VIGIV)” provides passive immunity against monkeypox by utilizing cross-reactive antibodies generated against the closely related vaccinia virus. Due to the genetic and antigenic similarities between vaccinia and mpox, antibodies raised against vaccinia can recognize and neutralize mpox, offering protection, especially in postexposure scenarios. Studies have shown that passive transfer of vaccinia-neutralizing antibodies can protect non-immunized individuals from severe mpox. 59 Depletion of B cells, which produce these antibodies, results in loss of vaccine-induced protection, emphasizing the crucial role of antibody-mediated immunity. Although antibodies are central to protection, T cell responses also contribute, as T cells activated by vaccinia virus vaccines recognize and respond to mpox due to conserved viral epitopes. 60 Together, VIG and immune responses from both B cells and T cells provide robust protection against mpox, particularly in high-risk individuals. At present, there is no published evidence regarding the efficacy of VIGIV in the treatment of mpox in humans. However, VIGIV may be considered as a treatment option for individuals with severe mpox, particularly those with advanced HIV, who may have a compromised immune system and a reduced capacity to mount an adequate antibody response to the infection. The provision of VIGIV for the treatment of mpox is facilitated under the “CDC’s Expanded Access Investigational New Drug (EA-IND) protocol.”6,61
Trifluridine
Trifluridine has demonstrated potential efficacy in the treatment of MPXV infections, primarily due to its broad-spectrum antiviral activity against orthopoxviruses, including MPXV. In vitro studies have shown that trifluridine effectively inhibits MPXV propagation, with evidence of its action against both vaccinia virus and MPXV in primary human fibroblast cultures.62,63 Although trifluridine exhibits antiviral properties, its clinical application is primarily as an adjunct therapy, particularly for ocular manifestations of MPXV. It is commonly used in combination with tecovirimat, which is the preferred treatment for progressive MPXV disease, underscoring its role in specific clinical scenarios rather than as a monotherapy for systemic infections. 62 While trifluridine shows promise, its current use is limited to treating localized ocular symptoms, and further research is needed to explore its potential in broader MPXV treatment regimens.
Postexposure prophylaxis
The CDC recommends the use of the MVA-BN vaccine for postexposure prophylaxis in individuals with known or suspected exposure to mpox. Vaccination is most effective when administered within 4 days of exposure, but may still offer protection if given up to 14 days after exposure. However, the evidence supporting the effectiveness of postexposure vaccination for mpox remains limited, with current data primarily derived from observational studies. More research is necessary to better understand the optimal timing and impact of postexposure vaccination in preventing or mitigating mpox infection. 64
Emerging therapeutic innovations
Monoclonal antibodies (mAbs) and gene-editing technologies show promise against mpox, though clinical validation remains pending. Combinations of human-like mAbs targeting both mature virion (MV) and extracellular enveloped virus (EV) forms have demonstrated superior postexposure protection and enhanced viral clearance in animal models compared to single-antibody therapies. Plant-derived mAbs also exhibit potent MV neutralization, though effective targeting of the EV form remains critical. Clustered regularly interspaced short palindromic repeats (CRISPR)-based systems, while largely experimental for mpox therapy, offer precision platforms for disrupting viral replication and modulating host responses. Strengthening these claims with additional evidence from in vivo studies, mechanistic insights, and clinical trials is essential to better define their translational potential.65,66
Monoclonal antibodies
Monoclonal antibodies (mAbs) represent a leading emerging therapeutic strategy against mpox. Combinations of human-like mAbs targeting both the MV and EV forms have demonstrated superior postexposure protection and accelerated viral clearance in animal models compared to single-antibody therapies.65,67 For instance, combined administration of MV33 and EV42 mAbs, each directed at a distinct viral form, achieved full protection and near-complete viral suppression in mice, highlighting a synergistic effect. Bispecific antibodies, capable of simultaneously engaging two different viral epitopes, have further enhanced antiviral activity and provided complete in vivo protection, suggesting a promising refinement of antibody-based therapies. Moreover, plant-derived mAbs targeting the EV form have exhibited potent neutralization, underscoring the potential for scalable biologics manufacturing. Despite these advances, optimization of antibody combinations, improved targeting of the EV form, and rigorous clinical validation are needed to translate these findings into effective human therapies. Collectively, the available evidence supports the therapeutic potential of mAbs, particularly those engineered to target multiple viral structures, for the treatment and prevention of mpox.67,68
The use of mAbs in treating mpox presents several challenges and limitations, primarily due to the complexity of the virus and the logistics of antibody production and deployment. These challenges include the need for targeting multiple viral forms as well as the regulatory hurdles. The MPXV generates two primary infectious forms: “MV and the EV.” To effectively disrupt viral replication and transmission, mAbs must target both forms. These antibodies have demonstrated robust production and significant neutralization potential, positioning them as a promising therapeutic option. Glycoengineered plant-based mAbs, such as the 7D11 antibody targeting the L1 transmembrane protein of vaccinia virus, have shown strong neutralization activity against MPXV, further supporting their utility in combating orthopoxvirus infections. 69 Plant-derived mAbs have been developed to address these viral particles, though their efficacy against both forms remains under investigation, necessitating further validation through rigorous preclinical and clinical studies. 66 The development of monoclonal and bispecific antibodies against MPXV proteins M1R and B6R represents another significant advancement. These antibodies have exhibited efficient neutralization of the authentic virus, highlighting their potential role in passive immunotherapy strategies for monkeypox. The scarcity of targeted antiviral interventions underscores the importance of establishing robust systems for efficient production and distribution, ensuring timely availability during outbreaks.66,70
The implementation of antibody-based therapies faces significant regulatory hurdles, including the complexities of approval processes, the need for rapid implementation in outbreak scenarios, and ensuring early administration of high-titer antibodies to maximize efficacy. Timely treatment requires well-coordinated healthcare delivery systems and proactive public health strategies for patient identification and treatment initiation. 71 Addressing these challenges through advancements in production technologies, regulatory pathways, and healthcare infrastructure is critical to realizing the full potential of mAbs in managing MPXV and other orthopoxvirus infections. Ongoing research and collaborative efforts are needed to refine these therapies and integrate them effectively into global outbreak preparedness frameworks.
Gene editing and RNA-based therapies
Gene-editing technologies, particularly CRISPR-Cas9, hold significant promise for the treatment of viral infections, including MPXV. By targeting essential genes in orthopoxviruses, these tools have demonstrated efficacy in reducing viral titers. However, their application to MPXV is still in the experimental phase, requiring further investigation to fully realize their therapeutic potential and address associated challenges. CRISPR-Cas9 has demonstrated the ability to target conserved genes in orthopoxviruses, achieving reductions in viral titers of up to 93.19% in vitro. Delivery systems such as adeno-associated virus (AAV) vectors have shown comparable efficacy, with titers reduced by as much as 92.97%. 72 These findings highlight CRISPR-Cas9’s potential for precise and effective antiviral intervention. The specificity of CRISPR-Cas9 for viral genomes minimizes the risk of off-target effects, an essential criterion for its safe therapeutic application. 73 While tools such as TALENs have been employed for creating gene-modified models, CRISPR-Cas9 is often preferred due to its simplicity, precision, and adaptability. In addition, CRISPR-based diagnostics, including SHERLOCK and DETECTR, have exhibited high sensitivity and specificity for detecting viral infections and may be tailored for MPXV detection.74,75 Although the use of CRISPR-Cas9 and similar tools for treating MPXV shows great promise, these approaches remain predominantly in the research phase. Future work should focus on optimizing delivery methods, ensuring scalability, and conducting rigorous safety and efficacy studies in vivo to translate these findings into viable clinical applications.
Furthermore, a study by Wang et al. introduces an innovative one-pot diagnostic platform combining fluorogenic RNA aptamers (Mango III) with CRISPR-Cas13a technology for the rapid and sensitive detection of MPXV. This platform overcomes key limitations of conventional diagnostic methods by eliminating the need for expensive fluorophore/quencher-labeled probes, while maintaining high sensitivity and specificity. The system integrates three essential components: (1) recombinase-aided amplification (RAA) for target amplification, (2) CRISPR-Cas13a for target recognition, and (3) the Mango III RNA aptamer as an affordable fluorescent reporter. Upon target recognition, Cas13a’s collateral cleavage activity degrades the RNA aptamer, resulting in a measurable fluorescence reduction when exposed to TO3-3 PEG-Biotin Fluorophore. The aptamer-coupled RAA-Cas13a system achieves a remarkable limit of detection of only four copies of MPXV DNA within 40 min, without requiring nucleic acid purification. The platform was validated using clinical specimens, demonstrating its potential as a point-of-care testing solution, particularly in resource-limited settings. This work represents a significant advancement in MPXV diagnostics, providing a rapid, user-friendly, and highly sensitive alternative to conventional PCR methods. The integration of fluorogenic RNA aptamers with CRISPR-Cas13a technology offers a versatile platform that could be adapted for detecting various pathogens, with the potential to transform disease surveillance and management in clinical and field settings. 76
RNA-based therapies represent innovative and promising strategies for the treatment of
RNA-based therapeutic approaches against Mpox virus.
RNA-based therapeutic approaches against Mpox Virus, including their mechanisms, targets, and outcomes.
miRNAs, microRNAs; Mpox, monkeypox; siRNA, small interfering RNA.
Prevention
Behavioral adaptations and impact on transmission
During the 2022 mpox outbreak, individuals at higher risk of infection, particularly gay and bisexual implemented behavioral changes to mitigate transmission risks. These adaptations included limiting sexual partners and the episodes of intercourse. Modeling studies indicate that the outbreak of initial deceleration was driven primarily by these self-protective behaviors among high-exposure populations, with subsequent contributions from vaccination efforts. 81
Vaccination
Two vaccines have been approved for mpox prevention in adults: “ACAM2000, a second-generation replication-competent single-dose smallpox vaccine, and Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN),” also known by its commercial names JYNNEOS, IMVANEX, and IMVAMUNE. MVA-BN, a third-generation replication-limited vaccine, is administered via two subcutaneous or intradermal doses, spaced 4 weeks apart. 82 Vaccinia-based vaccines, such as MVA-BN and ACAM2000, induce strong immune responses that cross-react with monkeypox, demonstrating the efficacy of this approach. 83 The presence of smallpox and mpox antibodies in human immunoglobulin preparations further supports VIG’s potential for postexposure prophylaxis. 84 In April 2024, MVA-BN became commercially available in the United States. However, its high cost has limited accessibility for uninsured or underinsured individuals, and vaccine availability remains constrained in low- and middle-income countries (LMICs), even those experiencing substantial mpox outbreaks. In a significant development, the World Health Organization (WHO) added MVA-BN to its prequalification list in September 2024. This designation is expected to expedite vaccine procurement by governments and international agencies, potentially improving access to mpox vaccines in LMICs, thereby enhancing global response capabilities to the outbreak. 85
Preexposure prophylaxis
Preexposure prophylaxis (PrEP) and its long-term impact on immune responses, particularly in the context of mpox vaccine development, involve a complex interplay of immunological factors. The MVA-BN vaccine, widely used for mpox, has demonstrated both safety and immunogenicity, with a two-dose regimen recommended to optimize neutralizing antibody responses, particularly in individuals living with HIV. 86 This includes gay, bisexual, and MSM individuals, as well as transgender and nonbinary persons who, in the last six months, have the history of a sexually acquired infection, had multiple sexual partners, attended commercial venues or large gatherings in areas with active mpox transmission, or are partners of those meeting these criteria. The guidance also extends to those who anticipate these behaviors. 87 The immunogenicity of MVA-BN is not significantly influenced by prior smallpox vaccination history, although a two-dose regimen remains recommended to achieve an optimal immune response. 86 However, for those at occupational risk, such as laboratory workers, MVA-BN and ACAM2000 are recommended for preexposure vaccination. Occupationally exposed individuals should receive an MVA-BN booster every 2 years or an ACAM2000 booster every 3 years. Routine vaccination is not advised for healthcare providers treating mpox patients, provided they have access to appropriate PPE. 82 Although vaccination with MVA-BN is not completely protective against mpox, emerging evidence suggests that breakthrough infections are typically less severe, with reduced risks of hospitalization or death.88–90 The two-dose MVA-BN vaccine shows an efficacy rate between 66% and 86%.91,92 However, the long-term effect of this immunity conferred by MVA-BN against mpox remains an area of ongoing research. 6
Emerging challenges in mpox treatment
The emergence of drug resistance in mpox presents a significant challenge to current treatment protocols and public health strategies, highlighting the need for alternative therapeutic approaches and enhanced surveillance systems. Although the mpox virus is a member of the DNA virus family, it demonstrates notable genomic variability, driven by a higher rate of nucleotide polymorphism. Factors such as increased global mobility and international travel have facilitated the spread of the virus across populations, enhancing opportunities for mutation.93–95 These dynamics contribute to the emergence of genetic variability, drug resistance, and multidrug-resistant strains of the mpox virus. 96 The molecular mechanisms underlying Mpox drug resistance primarily involve mutations in viral proteins that interfere with drug action. Tecovirimat, a widely used antiviral, targets the viral phospholipase F13, but resistance arises through mutations at the dimer interface of the F13L gene encoding the viral envelope protein targeted by the drug, thus preventing drug-induced dimerization.51,97,98 For instance, Cidofovir exhibits poor bioavailability and carries a risk of nephrotoxicity, while both cidofovir and brincidofovir are associated with adverse effects on hematopoietic and hepatic functions. These challenges underscore the urgent need for the development of innovative therapeutics targeting the mpox virus, aiming to address resistance issues and improve the safety and efficacy profiles of treatments. 99 Moreover, coinfections like HIV and syphilis can further complicate diagnosis due to similar dermatological manifestations. 100 Laboratory diagnosis of mpox primarily relies on nucleic acid amplification tests, especially real-time or conventional PCR targeting Orthopoxvirus and specifically monkeypox virus DNA. Samples are collected by vigorously swabbing lesion exudates, vesicular fluids, or crusts from multiple skin lesions to ensure sufficient viral DNA. Specimens must be transported separately in viral transport medium or dry tubes, avoiding mixing different sample types to prevent contamination. 101
Additionally, targeting other viral proteins such as thymidylate kinase (TMPK) and exploring drug repurposing strategies offer promising avenues for effective mpox treatment. 102 Although resistant strains are rare, with an estimated frequency of less than 1%, such cases have been linked to treatment failures and prolonged infections, particularly in vulnerable populations. This underscores the urgency of developing novel antiviral agents and adjunctive therapies to effectively manage severe cases. 18 To address the impact of drug resistance, public health strategies must focus on the development of new therapeutics, enhanced surveillance systems to monitor resistance patterns, and comprehensive prevention measures. Robust surveillance mechanisms are critical for detecting and responding to resistant strains, allowing for timely interventions and adjustments in treatment guidelines. Prevention strategies, including vaccination and targeted public health interventions, remain vital for reducing transmission and protecting high-risk groups.18,51,97 few other drugs have shown significant potential in the treatment of mpox infection. Ribavirin, for instance, has demonstrated therapeutic effectiveness, while gefitinib, an epidermal growth factor receptor (EGFR) inhibitor primarily used for late-stage non-small cell lung cancer, has exhibited promising antiviral activity against the mpox virus. Despite these advancements, drug repurposing efforts often remain reliant on serendipitous discoveries and traditional laboratory-based approaches. However, the advent of computational sciences has revolutionized drug development, significantly accelerating drug repurposing progress103–105 computer-aided drug discovery (CADD) has emerged as a pivotal tool in this domain, employing three primary strategies: high-throughput screening of small molecule libraries, as demonstrated by the identification of tecovirimat targeting the VP37 protein; structural optimization of existing drugs, such as the development of NPP669 through modifications of Cidofovir to enhance pharmacological properties; and novel drug design targeting specific viral functional sites, like DNA-dependent RNA polymerase (DdRp), a critical target for antiviral therapies. These computational advancements provide a systematic and efficient framework for identifying and optimizing therapeutic agents to combat mpox effectively. 18 Furthermore, network-based approaches have identified 268 candidate drugs for mpox treatment, with 23 demonstrating favorable safety profiles and significant interaction with viral targets. 106 Drug repurposing initiatives have primarily focused on targeting critical viral proteins, such as DNA polymerase, decapping enzymes, and envelope proteins, which play pivotal roles in viral replication and pathogenesis. 107 These findings provide a foundation for therapeutic innovation and the development of targeted interventions.
The advancement of multi-omics technologies and high-throughput screening (HTS) techniques has significantly enhanced the identification and characterization of molecular targets associated with the mpox virus. These advancements are pivotal for the development of novel therapeutics targeting unique viral mechanisms. Multi-omics approaches have elucidated gene expression patterns during mpox infection, identifying specific receptors and pathways that play critical roles in viral progression. By modulating these molecular targets, researchers can design drugs that are more precise in their therapeutic effects, optimize chemical structures for enhanced efficacy, and reduce adverse side effects through improved delivery and targeting methods. 18
In recent years, artificial intelligence (AI), notably machine learning and deep learning methodologies, has redefined the drug discovery practice, challenging conventional paradigms of drug design and development. 108 AI leverages extensive data from compound libraries to facilitate the efficient design and optimization of molecules targeting homologous proteins of the mpox virus. This approach has proven instrumental in screening for optimal antiviral drugs or identifying promising candidate compounds, significantly reducing the time and costs traditionally associated with drug development.109,110 However, no commercially available drugs have yet emerged from these AI-driven approaches, highlighting the need for further advancements and breakthroughs to realize their full potential. 111 These efforts represent a crucial step toward overcoming current challenges in mpox treatment and advancing the field of antiviral drug development.
Current efforts are centered on overcoming resistance through alternative therapeutic strategies, including targeting nontraditional viral proteins and utilizing repurposed drugs. However, the broader implications of viral evolution and resistance must be considered in these strategies. Continuous surveillance of viral mutations and the incorporation of adaptive approaches will be vital to maintaining the efficacy of mpox treatments over time. Moreover, at the individual level, education about mpox, adherence to proper personal hygiene practices, and the use of protective measures are essential for minimizing the risk of infection. Avoidance of potential sources of exposure, such as direct contact with infected individuals or contaminated materials, is critical. Consequently, the most cost-effective strategy for reducing the incidence and spread of mpox lies in the implementation of comprehensive preventive measures. These include public awareness campaigns, behavioral interventions, and infection control practices, rather than relying solely on the development and deployment of novel antiviral drugs. Prevention-focused approaches not only mitigate the immediate spread of the virus but also complement therapeutic strategies in managing outbreaks effectively. 18 This proactive approach ensures that therapeutic advancements remain resilient against emerging challenges in viral resistance and evolution (Figure 3).
Challenges and future direction in mpox treatment.
Current discourse in global health often emphasizes high-tech innovations such as gene editing, AI, and CRISPR, yet these remain largely experimental and inaccessible in many LMICs. 112 In contrast, low-cost, context-specific interventions—such as frugal innovations and health literacy programs—have demonstrated significant impact on improving health outcomes and access in these settings. For example, health literacy interventions tailored to LMIC populations have been shown to effectively increase knowledge and awareness, though their long-term sustainability and scalability require further study. Frugal innovations, which focus on creating affordable, adaptable, and culturally acceptable solutions, are crucial for overcoming systemic barriers and ensuring equitable healthcare delivery.113–115 A more balanced approach that integrates both high-tech advancements and proven, low-cost strategies is essential for meaningful progress in public health, particularly in resource-constrained environments.116,117
Conclusion
The challenges posed by mpox require a multifaceted strategy, integrating robust clinical trials, enhanced epidemiological surveillance, and the development of novel therapeutic approaches. Mpox is primarily transmitted through close skin contact, and while most cases result in self-limiting illness, severe disease and fatalities have been observed, particularly among immunocompromised individuals. Current first-line therapy is focused on supportive care, with antiviral therapy reserved for severe cases. Vaccination remains a cornerstone of prevention, particularly for individuals at high risk of exposure, and should be prioritized accordingly. Despite promising advances in mpox drug development, the emergence of drug-resistant strains and the potential for prolonged outbreaks emphasize the need for continued research and innovation. Clinicians must be aware of the importance of optimizing current treatments, exploring emerging antivirals, and strengthening preventive strategies to mitigate the impact of mpox and safeguard public health against future outbreaks.
