Multi-country monkeypox outbreak: situation update

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, balanced against the fact that mortality has remained low in the current outbreak.

In apparently newly affected countries, cases have mainly, but not exclusively, been confirmed amongst men who self-identify as men who have sex with men, participating in extended sexual networks. Person to person transmission is ongoing, still primarily occurring in one demographic and social group. It is likely that the actual number of cases remains an underestimate. This may in part be due to the lack of early clinical recognition of an infectious disease previously thought to occur mostly in West and Central Africa, a non-severe clinical presentation for most cases, limited surveillance, and a lack of widely available diagnostics. While efforts are underway to address these gaps, it is important to remain vigilant for monkeypox in all population groups to prevent onward transmission.

At present, transmission in apparently newly affected countries is primarily linked to recent sexual contacts. There is the 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 (face-to-face, skin-to-skin, mouth-to-mouth, mouth-to-skin) with infectious lesions or mucocutaneous ulcers including during sexual activity, respiratory droplets (and possibly short-range aerosols), or contact with contaminated materials (e.g., linens, bedding, electronics, clothing, sex toys).

The current risk for the general public remains low. There is a risk to health workers if they are in contact with a case while not wearing appropriate personal protective equipment (PPE) to prevent transmission; though not yet reported in this current outbreak, the risk of health care-associated infections has been documented in the past. Should monkeypox begin to spread more widely to and within more vulnerable groups, there is the potential for greater health ­­­impact as the risk of severe disease and mortality is recognized to be higher in immunocompromised individuals, including persons with poorly controlled HIV infection. While infection with monkeypox during pregnancy is not fully understood, limited data suggest that infection may lead to adverse outcomes for the foetus or newborn infant and for the mother.

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 virus, one first identified in West Africa (WA) and one in the Congo Basin (CB) region. The WA clade has in the past been associated with an overall lower case fatality ratio (CFR) of <1% while the CB clade appears to more frequently cause severe disease with a CFR previously reported of up to about 10%; both estimates are based on infections among a generally younger population in the African setting. In the period following the eradication of smallpox, more people were immune to orthopoxviruses through exposure to smallpox or receipt of smallpox vaccine. Therefore, initially most early cases of human monkeypox were among children who were vulnerable and therefore at risk of more severe disease.

Vaccination against smallpox was shown in the past to be cross-protective against monkeypox. Today, any continuing immunity from prior smallpox vaccination would in most cases 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. Protection for those who were vaccinated may have waned over time. The original (first generation) smallpox vaccines from the eradication programme are no longer available to the general public.

Smallpox and monkeypox vaccines, where available, are being deployed in a few countries to manage close contacts. Second- and third-generation smallpox vaccines have been developed to have an improved safety profile and one has been 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 agent, tecovirimat, has been approved by the European Medicines Agency, Health Canada, and the United States Food and Drug Administration for the treatment of smallpox. It is also approved in the European Union for treatment of monkeypox. 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 can 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 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 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 atypical symptoms, which includes a localized rash that may present as little as one lesion.  The appearance of lesions may be asynchronous and persons may have primarily or exclusively peri-genital and/or peri-anal distribution associated with local, painful swollen lymph nodes. Some patients may also present with sexually transmitted infections and should be tested and treated appropriately. 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 adapted to local settings, prompt isolation and rapid implementation of appropriate IPC measures (standard and transmission-based precautions, including the addition of respirator use for health workers caring for patients with suspected/confirmed monkeypox, and an emphasis on safe handling of linen and management of the environment), physical examination of 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 bacterial infection of skin lesions, ocular lesions, and rarely, severe dehydration, severe pneumonia or sepsis. Patients with less severe monkeypox who isolate at home require careful assessment of the ability to safely isolate and maintain required IPC precautions in their home to prevent transmission to other household and community members.

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 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 Information section below. Key updates from these documents as well as highlights from documents under development are provided below for ease of reference.

Surveillance and reporting 

As per IHR (2005) Article 6, a minimum data set (formatted as a case report form) for reporting under IHR has been developed and shared with Member States. The data will be compiled and shared publicly in aggregate form on a regular basis through WHO information products. A separate in-depth Case Investigation and Contact Tracing Form (CIF) for Member States has been also shared with Member States. This form can be used for investigation of exposure risks and transmission dynamics of cases and secondary infection risk in contacts. WHO is working to identify Member States who may be interested in sharing these detailed data, or analyses, to inform the global understanding of the current outbreak. A protocol to support implementation of the CIF is being also finalized.

WHO has also implemented the Case Reporting Form (CRF) and CIF in the Go.Data platform to facilitate local capture, analysis, and/or sharing of the relevant data. Analysis of transmission chains and network visualization have been used in past outbreaks to identify clusters, understand patterns of exposure, and quantify viral transmission across different settings. In the context of the current monkeypox outbreak, understanding these patterns of transmission will be critical not only in finding which control measures are effective, but will allow for the characterization of the extent of respiratory transmission and determining if multiple introductions (human or zoonotic) have occurred. To date, limited tools are available for countries to be able to graph these chains of transmission and identify clusters or contexts of transmission in real time. This presents an opportunity for Go.Data to be used by Member States, partners, and institutions to enhance outbreak response activities, mainly in the generation, visualization, and analysis of their chains of transmission. Through its “visualization” feature, Go. Data will allow countries to visualize, in real-time, chains of transmission which will facilitate the monitoring of disease progression as well as the identification of potential new cases that are missed through undetected circulation of the virus or new circulating clades. The Go.Data monkeypox outbreak template and associated metadata description can be obtained upon request by emailing [email protected], and technical support for implementation is available from WHO.

Laboratory testing and sample management

Details can be found in Laboratory testing for the monkeypox virus: Interim guidance (23 May 2022)

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 and avoid sharing of personal items (e.g. eating utensils, clothing, electronic devices, bedding); keeping hands clean with water and soap or alcohol-based gels; and maintaining respiratory etiquette.

If a person develops symptoms such as a rash with blisters on 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 isolate, be tested, undergo clinical evaluation to assess for complications, avoid skin-to-skin and face-to-face contact with others and avoid sex, including receptive and insertive oral, anal, or vaginal sexual intercourse, until all lesions have crusted, the scabs have fallen off and a fresh layer of skin has formed underneath. 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. As a precaution, WHO suggests the use of condoms consistently during sexual activity (receptive and insertive oral/anal/vaginal) for 12 weeks post recovery to reduce the potential transmission of monkeypox for which the risk is as yet not known.

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). In a previous outbreak in 2003 in the United States of America, owners of pet prairie dogs were infected through contact with their infected pets. Therefore, persons with monkeypox in any setting should be mindful of the theoretical risk of exposing animals, for example those who may be kept as pets in the household.

WHO is continually updating its content through Monkeypox Q&A, public communication platforms and other materials. Please refer to the WHO Guidance and Public Health Recommendations section below.

Gatherings

Gatherings and events where physical contact, including sex, may be involved may represent a conducive environment for the transmission of monkeypox virus if they entail close, prolonged or frequent interactions among people, which in turn could expose attendees to contact with lesions, body fluids, respiratory droplets and contaminated materials.

Planned gatherings in areas where monkeypox cases have been detected can be safely maintained with a few precautions and sharing of information as required. Furthermore, such events can be used as opportunities to conduct outreach with public health information for specific population groups. It is important to communicate early, often, 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 organisations that have direct and trusted relationship with affected populations is highly recommended.

The following precautionary measures can be considered to reduce risk of monkeypox transmission associated with such events:

• 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.
• 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 events and unplanned congregations (i.e.. gatherings in bars and pubs, house parties, private spaces, etc.).
• 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.
• 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; as such, they should be continued; skin-to-skin and face-to-face contact should be discouraged.
• Close contact with someone who has signs or symptoms consistent with monkeypox should be avoided, including not having intimate or sexual contact.
• Attendance lists for participants in gatherings can be introduced, if applicable, to facilitate contact tracing in the event that a monkeypox case is identified.
• Staff responsible for dealing with attendees who fall ill at the event should be provided with information on how to manage people with signs and symptoms consistent with monkeypox.
• 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 mass 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.

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 may have asymptomatic infection. 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 of persons with monkeypox from 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 to peri-domestic animals, especially rodents.

International travel and points of entry

Based on available information at this time, WHO does not recommend that Member States adopt any  measures that interfere with international traffic 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 or local travel, until  no longer considered a public health risk by a health care provider or public health unit. 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, immunization history including whether they have received smallpox vaccine or other vaccines (e.g. measles-mumps-rubella, varicella zoster vaccine, to support making a diagnosis), and information on close contacts as per WHO interim guidance on surveillance, case investigation and contact tracing for monkeypox (please refer to the WHO Guidance and Public Health Recommendations section below). 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 close 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 in any previously affected or newly affected areas.