Monkeypox Returns to Europe

The first cases of monkeypox (mpox) have resurfaced in Western Europe after a two-year hiatus. On 20 August, it was reported that at least one case had been detected in Sweden, believed to have originated from Africa. Prior to this, the disease had been identified in some Asian countries and in Africa, where it is indeed endemic. The World Health Organization (WHO) insists that there is no need for strict quarantine measures, as seen during the COVID-19 pandemic. However, it appears mpox has its own agenda and continues to spread across the globe.

To summarise, scientists have now identified two strains of monkeypox (mpox): the so-called mpox clade II, which caused the 2022 outbreak, and mpox clade I, currently responsible for the outbreak in East-Central Africa. Mpox clade I, more specifically its strain mpox clade Ib, is now causing the most significant impact in African countries.

In 2022, mpox clade II was recorded in 70 countries, according to WHO, with the majority of transmission occurring through sexual contact. It is believed that the mpox clade Ib strain emerged in the eastern part of the Democratic Republic of the Congo in 2023, before spreading to Rwanda and Burundi. This strain is considered significantly more virulent and severe in its consequences than clade II, which was observed in Europe in 2022.

The incubation period for mpox clade Ib ranges from 6 to 21 days, with the first symptoms usually appearing within 7 to 14 days. The most common symptoms include painful blisters or ulcers on the body, fever, headaches, muscle pain, swollen lymph nodes, and digestive issues. Although the transmission routes are not fully understood, it is known to spread through close contact, including sexual contact.

In 2024, mpox clade Ib has primarily spread in Africa. In the Congo, the spread of this strain was first observed in 2023, but by mid-August 2024, the epidemic had reached such significant proportions that WHO declared a global health emergency on 14 August, the second time in two years due to mpox. Since the current outbreak began, approximately 27,000 cases and over 1,100 deaths have been reported in the Congo. The majority of the deceased were children. The virus has spread to neighbouring countries, prompting WHO to recognise the issue as a global concern.

Photo: What You Should Know About Mpox. Source: WHO

On 19 August, WHO Director-General Tedros Adhanom Ghebreyesus issued interim recommendations for countries experiencing mpox outbreaks:

• Emergency coordination
• Joint surveillance and laboratory diagnosis
• Safe and scalable clinical care
• Risk communication
• Vaccination

On 20 August, the U.S. Department of Health and Human Services (DHHS) released detailed information about the 2022 outbreak and the current situation. Unlike WHO, DHHS estimated that the global outbreak of mpox clade II in 2022 resulted in over 95,000 cases across 115 non-endemic countries. The DHHS statement also warned that the new strain, mpox Clade I, generally leads to more severe infections and has a higher mortality rate than its predecessor, mpox Clade II.

As vaccination is considered a critical tool in combating the mpox outbreak, the United States has provided the Democratic Republic of the Congo with 50,000 doses of the JYNNEOS vaccine, which is approved by the Food and Drug Administration (FDA), free of charge.

On 15 August, it was reported that the first case of mpox clade Ib in Europe had been detected in Sweden, in a local resident who had returned from Africa. There is currently no information on further spread in Sweden, with local epidemiologists investigating the patient's prior contacts.

Additionally, four cases of the disease were recorded in Taiwan. On 20 August, the Taiwan Centers for Disease Control (CDC) reported that these cases were identified between 13 and 19 August. The report noted that these cases were not related to the mpox clade Ib strain currently spreading from Africa but were instead linked to the less dangerous mpox clade IIb, which was mentioned in 2022. On the same day, 20 August, a similar case (mpox clade IIb) was reported in Islamabad, Pakistan, involving an airline passenger arriving from the Persian Gulf.

Mpox Is Not the 'New COVID'

Hans Kluge, WHO Regional Director for Europe (Message on X, formerly Twitter, with edits)

As we consider mpox as a public health emergency of international concern for the second time in two years, I would like to convey three key messages on behalf of WHO Europe:

Message 1: Mpox is not the 'new COVID'. Whether it is mpox clade I, which is responsible for the current outbreak in East-Central Africa, or mpox clade II, which caused the 2022 outbreak that initially affected Europe and has since continued to circulate there, we already know a significant amount about clade II. However, we still need to learn more about clade I. Based on what we do know, mpox is primarily transmitted through skin-to-skin contact with lesions, including during sexual activity. 

Message 2: We know how to control mpox, and in the European region, we have implemented the necessary measures to eliminate its transmission entirely. Two years ago, we controlled the spread of the virus in Europe through direct engagement with the most affected communities—men who have sex with men. We established robust epidemic surveillance, thoroughly investigated new contacts with infected individuals, and provided evidence-based health advice. Behavioural changes, non-discriminatory public health measures, and vaccination against mpox helped control the outbreak. However, due to a lack of commitment and resources, we fell short of the final goal. Today, we see around 100 new cases of mpox clade II in the European region each month.

However, the current concern over clade I provides Europe with an opportunity to refocus on clade II by: 

• Strengthening surveillance and diagnosis of mpox;
• Providing health advice, including to travellers, based on science rather than fear, without stigma or discrimination;
• Procuring vaccines and antiviral treatments for those who may need them, based on a strategic risk assessment.
  

In summary, even as we increase vigilance against mpox clade I, we can—and must—aim to eradicate clade II in Europe once and for all. 

Message 3: The need for a coordinated response to mpox is now greatest in the African region. The Africa Centres for Disease Control and Prevention (Africa CDC) recently declared a continental emergency over mpox. Europe must act in solidarity by:

• Standing with individuals and communities affected by mpox, working directly with them to care for their health;
• Standing in solidarity with WHO's Africa office and its affected member states, both at this critical time and in the long term.

In 2022, mpox demonstrated its potential to spread rapidly across the globe. We can and must combat mpox together—across regions and continents. How we respond now and in the coming years will be a crucial test for Europe and the world.

Photo: Hans Kluge, WHO Regional Director for Europe, offers reassurance. Source: X (formerly Twitter) Hans Kluge

What's Next in Europe

Following a meeting on 19 August, European health authorities announced that, for now, they do not see a need for restrictive measures regarding the risk of spreading mpox clade I. They consider the risk to the general population from this infection to be "low" at present. This assessment includes both additional border controls and vaccination campaigns. The European Commission's Health Security Committee made this announcement yesterday after a joint meeting with the European Centre for Disease Prevention and Control (ECDC) and the European Medicines Agency (EMA).

More stringent control measures and quarantines for travellers arriving from African countries could be expected, but as of now, there are no recommendations from the relevant authorities. At the same time, the EU and the US appear to be quickly ramping up various forms of aid to African countries, primarily the Congo. For example, Danish biotech company Bavarian Nordic has announced it is considering increasing production of its mpox vaccine, even without current orders. An active vaccination campaign is set to begin in Congo and Nigeria next week, although, until now, vaccination was considered necessary only for high-risk groups, such as healthcare workers and men who have sex with men.