Mpox

Mpox (formerly monkeypox) or simian orthopoxvirosis (DNA virus) is caused by a virus close to that of human smallpox. It is a zoonosis present in Central and West Africa, and small mammals endemic to these regions are probably the reservoir. It was first identified in 1958 in an infected monkey, which gave it its original name, although the monkey, like humans, is only an accidental host. The first human case was described in 1970 in a child in the Democratic Republic of Congo (DRC). Confirmed cases and epidemics occur regularly in sub-Saharan Africa. Contact with the natural environment is a risk factor.

For the past 5-10 years, the number of cases has been rising steadily in Central and West Africa, with greater momentum since the epidemics in Nigeria in 2017-18 and worldwide since 2022 (clade IIb) and the emergence of a new clade (Clade Ib) in the east of the DRC in 2024, which led the WHO to declare a public health emergency of international concern ( PHEIC), first on 23 July 2022 and then more recently on 14 August 2024.

In 2022, the  PHEIC was declared when a global epidemic of a new clade II, clade IIb, was identified, mainly affecting men who declared having sex with men and/or multiple sexual partners. This epidemic was brought under control by vaccination and public health measures outside endemic areas, but the virus continues to circulate at a low level worldwide.

The USPPI> PHEIC of 14 August is linked to the emergence of the new clade Ib, its rapid spread in the east of the DRC with cases reported in neighbouring countries (Burundi, Rwanda, Uganda and Kenya) and the increase in the number of clinical cases in endemic regions of the DRC (clade Ia).

There are currently 3 major strains of the virus circulating:

• Clade Ia in Central Africa 
• Clade Ib: eastern DRC and neighbouring countries (Uganda, Kenya, Burundi and Rwanda)
• Clade II: West Africa and the 2022 global epidemic outside Africa (clade IIb).

The virus is transmitted by direct contact (e.g. injured skin or mucous membranes) with lesions or secretions of infected people or animals. Transmission occurs mainly by:

• Zoonotic transmission: (in particular Clade Ia)
• Prolonged sexual or non-sexual close contact (mainly Clade Ib and Clade IIb)
• Transmission during pregnancy from mother to child (with a significant risk of foetal death).

Transmission by contact with infected objects (e.g. linen) is possible, as is transmission via droplets of infected saliva in the event of prolonged face-to-face contact or via oropharyngeal lesions. It should be noted that there is currently no epidemiological data to support widespread transmission of the virus via the respiratory route.

As a precaution, the protective measures are AIR and CONTACT PLUS (see vigigerme measures).

See ‘Case definition’ document.

After an incubation period of one to 2 weeks (21 days maximum), the virus usually causes a febrile state, with adenopathy (cervical, inguinal), followed within 1-2 days by a cutaneous and/or mucosal rash, initially macular and then evolving into vesicles/pustules in the mouth, on the face, trunk and then towards the extremities (including the palms of the hands and soles of the feet). See ‘mpox lesion atlas’.

The number of lesions can vary greatly, as can their distribution on the body (sometimes a disseminated eruption, or, in the case of sexual contact, limited to the genitals). Lesions usually heal spontaneously within 2 to 3 weeks.

The main complications are bacterial superinfections (skin, ENT, sepsis, etc.), foetal death in utero or spontaneous abortion in pregnant women, and more rarely, disseminated forms with encephalitis and local complications depending on the location of the lesions.

An infected person is contagious from the appearance of the first symptoms until the end of the rash, i.e. until the last scabs on the skin have fallen off.

If there is any suspicion, the Emerging Viral Infections Reference Centre (CRIVE) has a PCR that can be used to make the diagnosis (smear of skin lesions sent to the laboratory in a viral transport medium). To send us a sample, please follow the instructions HERE. Throat swabs can also be taken from suspected patients before lesions appear.

Suspicions and confirmations should be sent to the CRIVE as category B UN 3373.

Since 1 March 2023, PCR for mpox has been invoiced and covered by compulsory health insurance. The deductible and co-payments apply.

There is no routine serology available.

If you have any suspicions, you can contact the Infectious Diseases consultation on 022 372 98 03 (This number is reserved exclusively for healthcare professionals, Monday to Friday, 8.30am to 6.30pm). The HIV Unit hotline (34 656) is the point of contact for all patients treated in the Unit, whether for HIV infection or for taking PreP. Outside these hours, you can contact the HUG central office.

If the diagnosis is confirmed, the disease must be reported within 24 hours to the cantonal doctor (for Geneva:mc-ge@hin.ch) and to the FOPH, by both the clinician and the laboratory.

Most infections heal spontaneously. There is therefore generally no need for specific treatment. Treatment consists of relieving symptoms and preventing complications (e.g. bacterial superinfection).

Several antivirals have shown an in vitro or in vivo effect in animals infected with the mpox virus (see review here). There are few data available for humans.
The HUG is participating in an international double-blind randomised controlled trial testing an antiviral, tecovirimat, in the treatment of mpox infection (UNITY). Tecovirimat is also available outside this study for patients with severe disease or at risk of severe disease.

In the DRC, the initial results of a clinical trial testing tecovirimat did not show that the treatment reduced the healing time of cutaneous and/or mucosal lesions. However, given the differences between the populations affected by the two clades, with their different clinical forms and care environments, the UNITY study is continuing in Argentina, Brazil and Switzerland, as is a similar study, the STOMP study, in the United States.  

The Swiss Society of Infectiology (SSI), in collaboration with the Federal Commission for Sexual Health, is drawing up management recommendations, which will be regularly updated. By 20.08.2024, treatment should be offered to :

• Patients at high risk of developing severe disease: immunosuppressed patients, pregnant women and children under 8 years of age
• Patients with severe (more than 100 lesions) or very severe (more than 250 lesions) disease or functional disability
• Patients hospitalised with organ dysfunction (encephalitis, myocarditis, sepsis, haemorrhagic lesions, etc.)

See document ‘Criteria for receiving treatment with tecovirimat either in the open-label arm of the UNITY study or as compassionate access outside the study’.

The vaccine available (Jynneos®, manufactured by Bavarian Nordic) is a third-generation non-replicative live vaccine developed from MVA-BN (Modified Vaccinia Ankara - Bavarian Nordic).  It was originally developed to combat human smallpox and offers cross-protection against mpox. Studies show a better tolerance profile and fewer side effects than first- and second-generation smallpox vaccines. It is considered highly effective in preventing severe forms of mpox, but not necessarily symptomatic infection.

The human smallpox virus was eradicated from the planet in the early 1980s. In Switzerland, people born before 1972 were vaccinated against human smallpox with a vaccine from the generation preceding the current Jynneos vaccine.

Vaccination with Jynneos® consists of 2 doses 1 month apart, with a booster after 2 years. The vaccine was approved by Swissmedic in March 2024.

The Swiss Expert Group on Travel Medicine recommends vaccination against mpox in the following situations (status as at 16 August 2024, will be updated regularly):

People travelling to the east of the Democratic Republic of Congo and Burundi in the event of :

• Working in a healthcare or laboratory environment
• Working with animals
• Planned sexual or other close physical contact

People staying or travelling worldwide in the event of :

•  Increased risk (e.g. laboratory workers handling the virus, men who have sex with men or trans people with several sexual partners), see Swiss recommendations.

Vaccination is not recommended for people with no risk factors in Switzerland, or for people travelling to other parts of the world (including sub-Saharan Africa).

Another indication for vaccination is exposure to an infected person in a professional or personal context (post-exposure prophylaxis).

If you come into contact with someone at work at the HUG, contact the “Service de santé au travail”.

Vaccination sites :

For people with a dense sexual network, such as men who have sex with men and transgender people who have male sexual partners and change them regularly, or for people at risk of sexual exposure in endemic or epidemic areas.

• HIV Unit
  Infectious Diseases Department
  Morier Building, 2nd floor
  Geneva University Hospitals
  Rue Gabrielle-Perret-Gentil 6
  1205 Genève

          Tél. : 022 372 96 17
          Mail : infectiologie.ambulatoire@hcuge.ch

• Checkpoint Genève
  Rue du Grand-Pré 9
  1202 Genève

          Tél. : 022 906 40 30
          Mail : vaccination.mkp@dialogai.org  et /ou secretariat.checkpoint@dialogai.org
          Site : Checkpoint Genève

• Geneva Health Group (Groupe santé Genève)
  Rue du Grand-Pré 9
  1202 Genève

          Tel : 022 700 15 00
          Site : https://groupesantegeneve.ch

For people at risk in their professional environment and those travelling to high-risk regions or where sexual promiscuity is a possibility.

• Department of Tropical and Humanitarian Medicine
  Geneva University Hospitals
  Morier Building, 3rd floor
  Rue Gabrielle-Perret-Gentil 6
  1205 Geneva

  Tel: 022 372 96 15
  Mail : info.medint@hug.ch

• Healthy Travel
• OFSP Mpox
• WHO Mpox
• Federal Food SAfety and Veterinrary Office SFVO – Surveillance des zoonoses
• Republic and Canton of Geneva - Mpox
• Infovac