Currently, the public health risk at the global level is assessed as moderate considering this is the first time that monkeypox cases and clusters are reported concurrently in many countries in widely disparate WHO geographical areas and without known epidemiological links to countries where monkeypox has been reported for many years. Cases have mainly, but not exclusively, been identified amongst men self-identified as part of extended sexual networks. The sudden appearance and wide geographic scale indicate that widespread human-to-human transmission is underway, for the time being still primarily in one demographic and social group, and the virus may have been present and undetected for several weeks or longer. Additionally, there is currently limited epidemiological and laboratory information, and the actual number of cases is likely an underestimate. This may in part be due to the lack of early clinical recognition of an infection previously known to occur mostly in West and Central Africa, limited surveillance and a lack of rapid diagnostics.
At present transmission in newly affected countries is primarily linked to recent sexual contacts. There is a high likelihood that further cases will be found without identified chains of transmission, including potentially in other population groups. Given the number of countries across several WHO regions reporting cases of monkeypox, it is highly likely that other countries will identify cases and there will be further spread of the virus. Human-to-human transmission occurs through close or direct physical contact with infectious lesions or mucocutaneous sores (through face-to-face, skin-to-skin, mouth-to-mouth, mouth-to-skin transmission) including during sexual activity, respiratory droplets (and possibly short-range aerosols), or contact with contaminated materials (e.g., linens, bedding and clothing).
Although the current risk to human health and to the general public remains low, the public health risk would be greater if this virus exploits the opportunity to establish itself as a widespread human pathogen. There is also a risk to health workers if they are not wearing appropriate personal protective equipment (PPE) to prevent contracting an infection; though not reported in this current outbreak, the risk of health care-associated infections has been documented in the past. There is the potential for increased health impact with wider dissemination in vulnerable groups, as the risk of severe disease and mortality is recognized to be higher among children and immunocompromised individuals, including persons with poorly controlled HIV. Infection with monkeypox in pregnancy is poorly understood, although limited data suggests that infection may lead to adverse outcomes for the foetus or newborn infant.
To date, all cases identified in newly affected countries whose samples were confirmed by PCR have been identified as being infected with the West African clade. There are two known clades of monkeypox, one identified in West Africa (WA) and one in the Congo Basin (CB) region. The WA clade has in the past been associated with overall lower mortality fewer than one in a hundred cases while the CB clade appears to cause more severe disease with a case fatality ratio (CFR) previously reported of up to one in ten; both estimates are based on infections among a generally younger population in the African setting.
Vaccination against smallpox was shown in the past to be cross-protective against monkeypox. However, any immunity from smallpox vaccination will only be present in persons over the age of 42 to 50 years or older, depending on the country, since smallpox vaccination programmes ended worldwide in 1980 after the eradication of smallpox. The original (first generation) smallpox vaccines from the eradication programme are no longer available to the general public. In addition, protection for those who were vaccinated may have waned over time.
Smallpox and monkeypox vaccines, where available, are being deployed in a limited number of countries to manage close contacts. While smallpox vaccines have been shown to be protective against monkeypox, one vaccine exists that is approved for prevention of monkeypox. This vaccine is based on a strain of vaccinia virus (known generically as modified vaccinia Ankara Bavarian Nordic strain, or MVA-BN). This vaccine has been approved for prevention of monkeypox in Canada and the United States of America. In the European Union, this vaccine has been approved for prevention of smallpox under exceptional circumstances. An antiviral to treat orthopoxviruses, tecovirimat, has been approved by the European Medicines Agency, the United States Food and Drug Administration and Health Canada. WHO has convened experts to review the latest data on smallpox and monkeypox vaccines, and to provide guidance on how and in what circumstances they should be used.
The advice provided hereafter by the WHO on actions required to respond to the multi-country monkeypox outbreak, is based on its technical work, and informed by frequent consultations with the following existing WHO advisory bodies: the Strategic and Technical Advisory Group on Infectious Hazards (STAG-IH); the ad-hoc Strategic Advisory Group of Experts on Immunization (SAGE) working group on smallpox and monkeypox vaccines; the Emergencies Social Science Technical Working Group; the Advisory Committee on Variola Virus Research; WHO Research & Development (R&D) Blueprint consultation: monkeypox research; the Scientific Advisory Group for the Origins of Novel Pathogens (SAGO); as well as by the outcome of ad-hoc meetings of experts.
All countries should be on the alert for signals related to patients presenting with a rash that progresses in sequential stages – macules, papules, vesicles, pustules, scabs, at the same stage of development or over all affected areas of the body – that may be associated with fever, enlarged lymph nodes, back pain, and muscle aches. During this current outbreak, many individuals are presenting with localized rash that may be in different stages of development (which is atypical for monkeypox) with peri-genital and/or peri-anal distribution associated with local, painful swollen lymph nodes. Some cases may have secondary bacterial infections, including sexually transmitted infections. These individuals may present to various community and health care settings including but not limited to primary and secondary care, fever clinics, sexual health services, infectious disease units, obstetrics and gynaecology, emergency departments, and dermatology clinics.
Increasing awareness among potentially affected communities, as well as health care providers and laboratory workers, is essential for identifying and preventing further cases and effective management of the current outbreak.
Any individual meeting the definition for a suspected case should be offered testing. The decision to test should be based on both clinical and epidemiological factors, linked to an assessment of the likelihood of infection. Due to the range of conditions that cause skin rashes and because clinical presentation may more often be atypical in this outbreak, it can be challenging to differentiate monkeypox solely based on the clinical presentation.
Caring for patients with suspected or confirmed monkeypox requires early recognition through screening protocols adapted to local settings, prompt, isolation and rapid implementation of appropriate infection, prevention and control (IPC) measures (standard and transmission-based precautions), physical examination of the patient, testing to confirm diagnosis, symptomatic management of patients with mild or uncomplicated monkeypox and monitoring for and treatment of complications and life-threatening conditions such as progression of skin lesions, secondary infection of skin lesions, and rarely, severe dehydration, severe pneumonia or sepsis.
Precautions (isolation) should remain in place until lesions have crusted, scabs have fallen off and a fresh layer of skin has formed underneath.
Information should reach those who need it most during upcoming small and large gatherings, particularly among social and sexual networks where there may be close, frequent or prolonged physical or sexual contact, particularly if this involves more than one partner. All efforts should be made to avoid the unnecessary stigmatization of individuals and communities potentially affected by monkeypox.
WHO is closely monitoring the situation and supporting international coordination working with Member States and partners.
For related WHO documents, please see the Public Health Response section above. Key updates from these documents and highlights from guidance under development are provided below for ease of reference.
Surveillance and reporting
A separate Case Investigation and Contact Tracing form for Member States’ own use is currently being finalized and will be shared as soon as available.
Laboratory testing and sample management
Risk communication and community engagement
Communicating monkeypox-related risks and engaging at-risk and affected communities, community leaders, civil society organizations, and health care providers, including those at sexual health clinics, on prevention, detection and care, is essential for preventing further secondary cases and effective management of the current outbreak. Providing public health advice on how the disease transmits, its symptoms and preventive measures and targeting community engagement to the population groups who are most at risk, is critical to minimize spread. Communication must be direct, explicit and engaging for the intended audience.
Anyone who has direct contact (e.g., face-to-face, skin-to-skin, mouth-to-mouth, mouth-to-skin) including but not limited to sexual contact, with an infected person can get monkeypox. Steps for self-protection include avoiding sexual contact with someone with a localized anogenital rash or skin lesions and limiting the number of sex partners; avoiding close contact with someone who has symptoms consistent with possible monkeypox infection; keeping hands clean with water and soap or alcohol-based gels; and maintaining respiratory etiquette.
As the summer festival, concert and other events season is beginning in the northern hemisphere, it is important to work with event planners to ensure safe gatherings. Some settings which entail close, prolonged and frequent interactions between people may pose a higher risk of disease transmission. However, such events can be used as opportunities to conduct outreach for specific population groups with public health messaging. It is important to communicate early, often, and consistently through known and trusted communication channels and in language and terminology used by the affected populations. Public health authorities and event managers should work together to ensure targeted information reaches event-goers before, during and after the event. Working closely with community-based and civil society organizations that have direct and trusted relationships with affected populations is highly recommended.
If a person develops symptoms such as a rash with blisters on the face, hands, feet, eyes, mouth, and/or genitals and peri-anal areas; fever; swollen lymph nodes; headaches; muscle aches; and fatigue they should contact their health care provider and get tested for monkeypox. If someone is suspected or confirmed as having monkeypox, they should self-isolate, be tested, undergo clinical evaluation to assess for complications, avoid skin-to-skin and face-to-face contact with others and abstain from sex, including insertive/receptive oral, anal, vaginal sexual intercourse, until all lesions have crusted, the scabs have fallen off and a fresh layer of skin has formed underneath. (See Clinical management and infection prevention and control for monkeypox). During this period, cases can get supportive treatment to ease monkeypox symptoms. Anyone caring for a person sick with monkeypox should use appropriate personal protective measures as mentioned above. Based on the precautionary principle, WHO suggests the use of condoms consistently during sexual activity (receptive and insertive oral/anal/vaginal) for 12 weeks after recovery to prevent the potential transmission of monkeypox.
Residents and travellers to countries that have long experienced monkeypox should avoid contact with sick mammals such as rodents, marsupials, non-human primates (dead or alive) that could harbour monkeypox virus and should refrain from eating or handling wild game (bush meat).
WHO is continually updating its content through the monkeypox Q&A, public communication platforms, and other materials. Please see links in Public Health Response section above.
Infection, prevention and control in healthcare settings
Implementation of appropriate IPC measures is essential to mitigate and control transmission of monkeypox, in health care and community settings; this includes application of a hierarchy of controls (administrative, environmental and engineering controls) and the use of PPE in reducing the risk of exposure to monkeypox within health care settings.
Health workers should apply standard precautions regularly, this includes conducting a risk assessment for every patient interaction, respiratory hygiene and cough etiquette, patient placement, PPE, aseptic technique, safe injections and sharps injury prevention, environmental cleaning and disinfection, proper handling of laundry and linen, decontamination and reprocessing or reusable patient care items and equipment, and waste management.
WHO advises that transmission-based precautions be implemented for any suspected or confirmed case of monkeypox.
Clinical management and treatment
Patients with monkeypox should be given symptomatic treatment for mild symptoms such as antipyretics for fever and analgesics for pain. Skin lesions should be kept clean and adequate nutrition and rehydration is important. Patients should be counselled about signs and symptoms of complications that require urgent care.
Though uncommon, patients with monkeypox may develop severe and life-threatening complications. For example, the confluence of skin lesions is susceptible to bacterial skin and soft tissue infections such as cellulitis, abscesses, and necrotizing soft tissue infections requiring meticulous local wound care and, in some cases, antimicrobial therapy. Subcutaneous accumulation of fluid in the crusting phase may lead to intravascular depletion and shock as well as exfoliation resulting in areas of skin that may require surgical debridement and grafting. Other complications which are rare, include severe pneumonia and respiratory distress; corneal infection which may lead leading to vision loss; loss of appetite; vomiting and diarrhoea leading to severe dehydration, electrolyte abnormalities and shock; cervical lymphadenopathy leading to retropharyngeal abscess or respiratory compromise; sepsis or septic shock; and in rare cases encephalitis and death. It therefore follows that clinical care should focus on management of clinical syndrome, maintenance of nutritional and hydration status and prevention of complications and sequelae, as and when needed.
In patients with monkeypox, antivirals should be used under randomized clinical trials with collection of standardized clinical and patient outcome data to rapidly increase evidence generation on efficacy and safety. If this is not possible, antivirals may be used under expanded access protocols, such as Monitored Emergency Use of Unregistered and Investigational Interventions (MEURI). See reference for WHO R&D blueprint for additional information.
The goal of the global outbreak response for monkeypox is to control the outbreak, and to effectively use public health measures to prevent onward spread of the disease. Judicious use of vaccines can support this response.
One vaccine was recently approved for monkeypox. Some countries may hold smallpox vaccine products which could be considered for use according to national guidance. Vaccines may potentially be available in limited quantities through national authorities, depending on the country.
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Control of monkeypox outbreaks primarily relies on public health measures including surveillance, contact-tracing, isolation and care of patients. While smallpox vaccines are expected to provide some protection against monkeypox, clinical data are limited.
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Most interim vaccination recommendations provided here concern off-label use.
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Some countries have maintained strategic supplies of older smallpox vaccines from the Smallpox Eradication Programme (SEP) which concluded in 1980. These first-generation vaccines held in national reserves are not recommended for monkeypox at this time, as they do not meet current safety and manufacturing standards.
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Many years of research have led to the development of new and safer (second- and third-generation) vaccines for smallpox, some of which may be useful for monkeypox and one of which (MVA-BN) has been approved for the prevention of monkeypox.
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The supply of newer vaccines is limited and access strategies are under discussion.
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Based on currently assessed risks and benefits and regardless of vaccine supply, mass vaccination is not required nor recommended for monkeypox at this time.
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Human-to-human spread of monkeypox can be controlled by public health measures including early case-finding, diagnosis and care, isolation and contact-tracing.
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All decisions around immunization with smallpox or monkeypox vaccines should be by shared clinical decision-making, based on a joint assessment of risks and benefits, between a health care provider and prospective vaccinee, on a case-by-case basis.
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Post-exposure prophylaxis (PEP): For contacts of cases, PEP is recommended with an appropriate second- or third-generation vaccine, ideally within four days of first exposure (and up to 14 days in the absence of symptoms), to prevent the onset of disease.
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Pre-exposure prophylaxis is recommended for health workers at high risk of exposure, laboratory personnel working with orthopoxviruses, clinical laboratory personnel performing diagnostic testing for monkeypox, and outbreak response team members as may be designated by national public health authorities.
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Vaccination programmes should be accompanied by a strong information campaign, robust pharmacovigilance, and conduct of vaccine effectiveness studies under rigorous clinical trial protocols with standardized collection of clinical and outcome data.
One Health
Various wild mammals have been identified as susceptible to monkeypox virus in areas that have long experienced monkeypox. These include rope squirrels, tree squirrels, Gambian pouched rats, dormice, non-human primates, among others. Some species are asymptomatic, especially those suspected of being reservoirs (rodents). Other species, such as monkeys and great apes, show skin rashes typical of those found in humans. Thus far, there is no documented evidence of domestic animals or livestock being affected by monkeypox virus. There is also no documented evidence of human-to-animal transmission of monkeypox. However, there remains a hypothetical risk of human-to-animal transmission, as such appropriate measures such as physical distancing from persons with monkeypox to domestic pets, proper waste management to prevent the disease from being transmitted from infected humans to susceptible animals at home (including pets), in zoos and wildlife reserves, and also to peri-domestic animals, especially rodents.
Gatherings may represent a conducive environment for the transmission of monkeypox virus if they entail close, prolonged and frequent interactions among people, which in turn could expose attendees to contact with lesions, body fluids, respiratory droplets and contaminated materials. Postponing or cancelling gatherings in areas where monkeypox cases have been detected is currently not required as a default measure. The following precautionary measure can be considered to decrease risk of monkeypox transmission associated with such events:
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Event organizers should be aware of the epidemiology of monkeypox in the host area, its modes of transmission and prevention, and what action should be taken if a person develops signs and symptoms compatible with monkeypox, including where appropriate care can be sought. This information should be shared with prospective attendees and all those involved in the event planning and delivery.
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Gatherings should be used as opportunities for information outreach and community engagement; attention should also be dedicated to the social context in which the event takes place, with a focus on individual risk behaviours associated with side gatherings, unplanned congregation, and unstructured socialization in public or private spaces.
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People with signs and symptoms consistent with monkeypox should refrain from close contact with any other individual and should avoid attending gatherings. They should follow advice issued by relevant health authorities.
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Although monkeypox and COVID-19 spread between people differently, some of the COVID-19 measures applied during social gatherings, such as keeping a physical distance and practicing regular handwashing, are also effective against the transmission of monkeypox virus.
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As skin-to-skin, mouth-to-mouth and mouth-to-skin transmission during sexual activity has been frequently reported as a likely source of infection during the current monkeypox outbreak, close contact with someone who has signs and symptoms consistent with monkeypox should be avoided, including sexual contact; overall risk can be lowered by engaging in safe sexual practices, limiting the number of sexual partners, and practicing good personal hygiene. Attendance lists for participants in gatherings can be introduced, if applicable, to facilitate contact tracing if a monkeypox case is identified.
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Staff responsible for dealing with attendees who fall ill at the event should be provided with information on how to identify and manage people with signs and symptoms consistent with monkeypox.
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Risk communication and community engagement activities, as well as measures for early detection of international travelers with signs and symptoms consistent with monkeypox at points of entry should be considered in host countries where monkeypox cases have been reported.
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Attendees should always be reminded to apply individual-level responsibility to their decisions and actions, with the aim of preserving their health, that of the people they interact with, and ultimately that of their community. This is especially important for spontaneous or unplanned gatherings.
As it is standard practice for gatherings, and even more so during the COVID-19 pandemic, authorities and event organizers are invited to apply the WHO-recommended risk-based approach to decision-making, and tailor it to the large or small social events under consideration. In the context of the current outbreak, monkeypox-associated risks should be considered and factored in.
International travel and points of entry
Based on available information at this time, WHO does not recommend that States Parties adopt any international travel-related measures for either incoming or outgoing travellers.
Any individual feeling unwell, including fever with rash-like illness, or being considered a suspected or confirmed case of monkeypox by jurisdictional health authorities, should avoid undertaking any travel, including international, until declared as no longer constituting a public health risk. Any individual who has developed a rash-like illness during travel or upon return should immediately report to a health professional, providing information about all recent travel, smallpox immunization history, and information on close contacts as per WHO interim guidance on surveillance, case investigation and contact tracing for monkeypox. Individuals who have been identified as contacts of monkeypox cases and, therefore, are subject to health monitoring, should avoid undertaking any travel, including international, until completion of their health monitoring period.
Public health officials should work with travel operators and public health counterparts in other locations to contact passengers and others who may have had contact with an infectious person while travelling. Health promotion and risk communication materials should be available at points of entry, including information on how to identify signs and symptoms consistent with monkeypox; on the precautionary measures recommended to prevent its spread; and on how to seek medical care at the place of destination when needed.
WHO urges all Member States, health authorities at all levels, clinicians, health and social sector partners, and academic, research and commercial partners to respond quickly to contain local spread and, by extension, the multi-country outbreak of monkeypox. Rapid action must be taken before the virus can be allowed to establish itself as a human pathogen with efficient person-to-person transmission in areas that have long experienced monkeypox, as well as in newly affected areas.
