Mpox (Monkeypox)

The mpox (formerly known as the monkeypox)virus is largely spread through close and primarily sexual contact. Cases of the disease are generally mild. A vaccination is available.

Virus and transmission

The mpox virus is a member of the orthopoxvirus family. Two mpox clades have been identified to date:

  • Clade I (so far spread in Africa)
  • Clade II (known variant in Switzerland and Europe)

Several African countries have reported increases in their numbers of cases of Clade I mpox. In view of this, the World Health Organization (WHO) has now declared a public health emergency of international concern (PHEIC).

The mpox virus is primarily transmitted amoung humans through direct contact of the skin or mucous membranes, or via contact with infected secretions from one or more blisters or lesions on the skin or the mucous membranes of a person already infected, and especially via sexual contact.

The mpox virus can also spread via scabs, respiratory secretions and/or bodily fluids; and pregnant women who are infected can transmit the virus to the foetus via the placenta. Whether the virus can also be transmitted via semen, vaginal secretions, urine or faeces has not yet been established.

Pathology

Mpox can occur between 5 and 21 days after close contact with an infected person. The severity of the symptoms of the resulting disease varies from case to case.

Some infected persons develop only isolated and mild symptoms. The skin rash is often unremarkable, with few or only isolated blisters or lesions. These blisters and lesions may be painful or itchy, and can develop at any stage in the course of the disease. The infection may also cause flu-like symptoms (such as fever, chills, headache, muscle ache, backache, a sore throat and similar) and/or symptoms in the genital and anal area (pain, bleeding, inflammation).

A person with mpox may be infectious themselves from the time the first symptoms appear until the skin rash has disappeared, i.e. until the last scabs have fallen off.

No long-term effects of an mpox infection have yet been detected. Immunocompromised persons, infants, children and pregnant women seem to be at a higher risk of developing a more severe case of the disease.

The treatment of mpox consists primarily in treating its symptoms. In particularly severe cases, an antiviral therapy may also be conducted. The appropriate medicine is available in Switzerland.

Spread and incidence

The mpox virus is likely to have originated among rodents in West and Central Africa, which may have then passed it on to humans. A few occasional cases or minor outbreaks of the disease had been reported from these West and Central African regions up to May 2022. Elsewhere, apart from one outbreak in the USA in 2003, only isolated cases had been reported, among persons who had recently travelled to the African regions concerned.

Exceptionally large numbers of Clade II mpox infections were first seen worldwide – and in Switzerland, too – in summer 2022. Only sporadic cases have been reported since autumn 2022. What has been observed – both in Switzerland and worldwide – is that the cases reported have particularly (but not exclusively) involved men who have sex with men (MSM) and trans people with multiple and changing male sexual partners. The risk of infection for the broader population is considered low.

Clade I mpox continues to circulate endemically in Central Africa. Since September 2023, the WHO has observed an increase in the number of infections – especially of a new mpox variant designated Clade Ib – in the Democratic Republic of the Congo, with a recent spread to several neighbouring countries. On 14 August 2024, the WHO declared this epidemic spread of mpox a public health emergency of international concern (PHEIC).

A first confirmed case of Clade Ib mpox was reported in Sweden on 15 August 2024. The person concerned had recently returned from a country affected by the epidemic.

Given the international mobility of travellers today, further cases of mpox outside Africa are likely to be reported in the next few weeks.

In Switzerland, the epidemiological situation remains stable, with only a few sporadic cases of Clade II mpox being reported and no cases of clade I.

Prevention

Persons at risk can basically protect themselves from mpox infection by adapting their behaviour - particulary by avoiding contact with infected individuals.

A preventive vaccination (Jynneos® from Bavarian Nordic) may also be administered. The available vaccine (Jynneos®) is also assumed to be effective against Clade I infection. The vaccine is considered both safe and highly effective in preventing severe mpox infections.

Mpox vaccination is advised for anyone who may be exposed to the virus in the course of their work (such as persons working on the virus in laboratories), for men who have sex with men and for trans persons who frequently change their sexual partners.

Vaccination is also possible and recommended for anyone who suspects that they may have been in risk-bearing contact with a person with a confirmed or probable case of mpox. Such precautionary post-exposure vaccination should be administered within four to 14 days after such contact with the person concerned.

It is assumed that any person who has already experienced Clade II mpox infection or who is fully mpox-vaccinated will also be protected against severe Clade I mpox development.

A booster mpox vaccination is recommended in the event of continued risk of mpox infection. Any such booster should be administered no less than two years after the second dose of the original mpox vaccination.

Anyone seeking an mpox vaccination will need to discuss this in advance with a specialist health professional.

Responsibility for providing such vaccinations and (in particular) specifying the vaccination centres rests with the Swiss cantonal authorities. Information on the availability of such vaccinations and the relevant health specialists is available from the cantonal healthcare authorities.

Your health insurance will cover the costs of the vaccination (i.e. of the vaccine and its administration). For further details, please see the Mpox vaccination factsheet (available in German and French).

And for persons with sexual relations:
do the safer sex check at www.lovelife.ch

Recommendations when travelling to Africa

Mpox can be contracted through contact with animals carrying the virus (and from rodents in particular) or through contact with infected persons.

For persons travelling to regions known to be affected by the present mpox epidemic who adhere to the recommended preventive measures (e.g. avoiding contact with wild animals and potentially infected individuals), the risk of mpox infection remains very low. But close physical (and above all sexual) contact will substantially increase the risk of such infection. So all travellers to these regions are advised to avoid such situations as much as possible.

Further information and specific instructions and advice have also been compiled by the Swiss Expert Committee for Travel Medicine (ECTM) and are available at www.healthytravel.ch (keyword “mpox”).

Vaccination against mpox in line with the present recommendations is advised in particular for members of aid and relief organisations who may be at risk of exposure to the mpox virus through their humanitarian work in risk areas.

The costs of travel vaccinations are generally not reimbursed by Swiss compulsory health insurance. This service must therefore be paid for by the immunized persons themselves. If such vaccination is required or advised for work purposes, the costs will be covered by the employer.

Last modification 20.12.2024

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