Mpox

What is Mpox?

Mpox is a viral disease that is caused by two distinct clades of the monkeypox virus (MPXV), known as Clade I and II.

Prior to 2022, mpox were primarily reported in parts of Central (Clade I) and West Africa (Clade II) where it is endemic. Almost all mpox cases occurring outside of Africa were linked to international travel to endemic regions or through imported animals.

2022 – 2023 global outbreak of MPXV Clade IIb: In May 2022, cases of mpox caused by MPXV Clade IIb were reported concurrently in multiple countries outside of Africa, which were not historically known to be endemic to mpox, including in Singapore. On 23 July 2022, the World Health Organization (WHO) declared the ongoing outbreak of mpox to be a Public Health Emergency of International Concern (PHEIC) due to its global spread. The PHEIC status was subsequently lifted on 10 May 2023 following a global decline in mpox cases and deaths. Nonetheless, mpox continues to be transmitted at low levels globally.

2023 – 2024 outbreak in Africa: In 2023, the Democratic Republic of the Congo (DRC) reported a significant increase in mpox cases and deaths. Unlike the global outbreak associated with MPXV Clade IIb, the virus circulating in the DRC is of the endemic Clade I, which has thus far only been detected within the African continent. From July 2024, several countries in the region, including those where historically mpox Clade I was not endemic, have also reported mpox cases and outbreaks.

On 14 August 2024, the WHO declared that the mpox outbreak in the DRC and the growing number of countries in Africa constitutes a PHEIC. This follows the Africa Centres for Disease Control and Prevention’s declaration of a Public Health Emergency of Continental Security on 13 August 2024. While there is cross-border spread of mpox Clade I in parts of Central and East Africa, the Clade I outbreak has thus far largely remained within the African continent. Outside of Africa, mpox Clade I has been detected in Sweden, Thailand, India, Germany, United States of America and Canada which have each reported one case in travellers since August 2024, but which have not led to further local spread.

Click here for the latest WHO update on the mpox situation

List of Affected Countries

As of 16 December 2024, 1200H, the areas/countries at risk of transmission of mpox Clade I cases are:

1. Burundi

2. Cameroon

3. Central African Republic

4. Democratic Republic of the Congo

5. Gabon

6. Kenya

7. Republic of Congo

8. Rwanda

9. Uganda

10. United Kingdom (London and Leeds^#)

^#Case had prior travel history to an affected country in Africa.

Areas/Countries previously reporting mpox Clade I cases, that are no longer at risk of mpox Clade I transmission*:

1. Canada (Manitoba)

2. Germany (Cologne)

3. India (Kerala)

4. Sweden

5. Thailand

6. United States of America (California)

7. Zambia

8. Zimbabwe

^* There is no evidence of further transmission from these areas/countries.

Visit the World Health Organization page for more information on regions and countries that have reported mpox Clade I and II cases.

Local Situation Update

Please refer to the MOH Weekly Infectious Diseases Bulletin for the number of confirmed mpox cases in Singapore.

To date, all mpox infections detected in Singapore have been the milder Clade II infections.

What are the symptoms of Mpox?

Clade I infections have historically been characterised by more severe disease than Clade II infections.

Symptoms for both clades are indistinguishable and may include:

• Skin rash often starting from the face before becoming generalized including involvement of palms and soles. However, presentation in the global outbreak of Clade II involves only a few or single localised lesions, especially in the genital and groin areas, which do not spread further.

• Fever

• Headache

• Backache

• Swollen lymph nodes

• Muscle ache

• General feeling of exhaustion or profound weakness

What are the potential complications of Mpox?

Based on currently available data, individuals who are at higher risk of severe illness include young children, pregnant women or immunocompromised individuals.

How does Mpox spread?

Mpox can spread through physical contact with infected individuals, skin lesions and body fluids, contaminated materials and environments, or exposure to respiratory secretions. The virus can also spread from animals to humans, e.g. through bite or scratch from an infected animal, bush meat preparation, or direct contact with the blood, body fluids, or skin or mucosal lesions of infected animals.

In the global outbreak of MPXV Clade IIb, the main mode of transmission is via close physical or prolonged contact, such as face to face and skin to skin contact including sexual contact. Many cases have been identified in individuals who reported intimate contact (including sexual contact) with infected people. Cases have also been reported where infection was attributed to household transmission. Regardless of sexual orientation, persons engaging in high-risk sexual behaviours, such as having multiple or casual sexual partners are most at risk of infection in the context of the current outbreak.

Food (other than bushmeat) has never been identified as being associated with human cases of mpox. Currently, there is also no evidence that food or food packaging is a likely source or route of transmission of the virus. As such, the risk of mpox transmission through food is low. Please refer to SFA's website for more information.

The incubation period is about 5 to 21 days.

How do I prevent Mpox?

Members of the public are strongly advised to maintain vigilance and take the following precautions, where relevant:

• Observe and practise good personal hygiene at all times.

• Wash your hands regularly with soap, especially before handling food or eating, after going to the toilet, or when hands are dirty from coughing or sneezing. If water is not available, use an alcohol-based hand sanitiser that contains at least 60% alcohol.

• Avoid contact with persons who are unwell (e.g., those with rash or other lesions).

• Avoid sharing common items that may be contaminated with bodily fluids.

• Practise safe sex, including avoiding high-risk sexual activities such as having multiple sex partners or engaging in casual sex.

• When travelling, avoid feeding or touching animals, especially stray or wild animals, and the consumption of bush meat.

• Travellers from countries affected by mpox should monitor for symptoms for 21 days upon their return from these countries. Please refer to MOH Health Advisory for Travellers for precautionary measures to be taken when travelling.

• Seek medical attention immediately if you become unwell or develop symptoms such as sudden onset of high fever, swollen lymph nodes and rash, and inform the doctor of your travel or exposure history.

How is Mpox treated?

Treatment is typically symptomatic.

The MVA-BN (JYNNEOS), a third-generation smallpox vaccine, is currently available as Post Exposure Prophylaxis (PEP) for persons who have been identified to be close contacts of confirmed mpox cases. While JYNNEOS is estimated to provide over 80% protection against mpox, current data remains limited in concluding the level and duration of protection conferred by vaccination, and persons are advised to continue adhering to the recommended precautions against the disease.

In line with international recommendations, mass population-wide vaccination is currently not recommended as a preventive strategy for mpox, as the risk to the general public remains low with disease transmission predominantly via close physical or prolonged contact.

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