UPDATE ON PUBLIC HEALTH PREPAREDNESS MEASURES FOR MPOX CLADE I

As part of a whole-of-government effort, the Ministry of Health (MOH) has coordinated public health preparedness measures to respond to a mpox Clade I epidemic, based on what we know about the virus and disease so far. We are monitoring the situation closely with our international counterparts, and are ready to respond decisively should the situation change. 

Response Measures

Borders

2. While there are no direct flights between Singapore and any mpox outbreak country thus far, MOH, together with the Ministry of Transport and the Immigration and Checkpoints Authority, have put in place temperature and visual screening at Changi and Seletar airports for inbound travellers and crew arriving on flights from places where they may have been exposed to mpox Clade I outbreaks. Similar screening measures have also been implemented at sea checkpoints for crew and passengers arriving on ships from mpox-affected areas.

3. Health advisories have been put in place at air checkpoints, so that travellers can take the necessary personal precautions to avoid being infected. Travellers are strongly advised to adhere to the advisory, especially if they are travelling to and from affected countries.

4. All travellers are required to report mpox-related symptoms (e.g. fever or rash) and travel history through the SG Arrival Card. Travellers who have fever, rash and/or symptoms compatible with mpox will be assessed by doctors at the borders, and subsequently referred to hospitals for further assessment and testing, if necessary.

Detection, Tracing and Isolation

5. MOH has notified all medical practitioners and healthcare institutions to be vigilant in detecting and reporting all mpox cases to MOH immediately, including and especially suspected Clade I infections. Suspect cases will be transferred to hospitals for further assessment and treatment, if necessary.

6. Upon confirmation of a Clade I case, MOH will immediately initiate contact tracing. Close contacts of the case will be quarantined in a designated government quarantine facility. The quarantine period is currently set at 21 days, which is the incubation period observed in Africa.  

Testing and Treatment

7. All suspect Clade I cases identified by primary care providers will be conveyed to designated hospitals for further assessment and testing. Testing for mpox is conducted at the National Public Health Laboratory through polymerase chain reaction tests on swabs of skin lesions. To date, there have yet to be point-of-care rapid test kits that are sufficiently accurate in diagnosing mpox. 

8. Adult cases will be conveyed to the National Centre for Infectious Diseases (NCID) while paediatric cases will be conveyed to KK Women’s and Children’s Hospital. Adult-child family dyads will be conveyed to the National University Hospital. Cases will be isolated while pending test results. All cases who test positive for Clade I will continue to be isolated in healthcare facilities until they are no longer infectious, to prevent further exposure to the community. 

9. The treatment of mpox cases is mainly through supportive care to help manage symptoms and prevent complications. While there are currently no specific therapeutics approved for the treatment of mpox infection, antivirals such as Tecovirimat will be prescribed for treatment of mpox cases with severe disease. This is aligned with the practices of other public health agencies.

10. MOH will continue to monitor new developments and assess the safety, efficacy, and suitability of emerging mpox therapeutics in meeting the needs of our population.

Other Community Measures

11. Based on current evidence that mpox is spread mainly through close physical contact, such as within households, we do not recommend wearing a mask for people who are well. However, should there be evidence of significant respiratory transmission, such as outside of households and in public areas, MOH will consider implementing masking on public transport, and in crowded indoor places. 

12. In preschools and schools (including special education schools), existing measures and protocols for other infectious diseases, such as hand, foot and mouth disease, remain relevant. These include maintaining good hygiene practices, conducting visual screenings for symptoms for students, as well as outbreak management measures such as isolation, contact tracing, decontamination of premises, and temporary closure of specific classes or schools to contain disease spread.

13. Together with the Ministry of Manpower and National Environment Agency, we are conducting wastewater testing at migrant worker dormitories and the Onboard Centre. Temperature screening and visual screening have also been put in place for newly arrived work permit holders at the Onboard Centre. In the event of any mpox cases being detected, there are protocols in place for isolation, transport of suspect cases to hospitals for testing and assessment, and containment measures to support workers in their recovery and prevent any further spread within the dormitories.

Vaccination

14. The mpox Clade I virus appears to be less transmissible compared to respiratory viruses such as Influenza or COVID-19.  Hence, based on current understanding of the disease epidemiology of mpox Clade I, and the fact that contact tracing and quarantine will further suppress transmission, population-wide mpox vaccination is not recommended for now. There is also no vaccination recommendation for travellers to mpox-affected countries. 

15. In addition, there is good evidence indicating that smallpox vaccination renders cross-protection against mpox. Since smallpox vaccination was required in Singapore until early 1981, there will be some mpox immunity among a significant segment of the Singapore population, i.e. those who are 45 years old and above. 

16. JYNNEOS, a live attenuated (non-replicating) vaccine, has been approved for use in Singapore for protection against mpox and smallpox. We will administer this selectively, to two groups. 

17. First, for healthcare workers who are at the highest risk of exposure to mpox.  Personal protective equipment and infection control protocols remain the key mode of prevention. However, to further protect this group, such as those working in the NCID who need to render direct care and will be in very close contact with mpox Clade I cases, JYNNEOS will be offered as a pre-exposure prophylaxis to provide additional protection. 

18. Second, for close contacts of confirmed mpox cases, the Expert Committee on Immunisation has recommended a single dose of the JYNNEOS vaccine to be offered and administered within 14 days of exposure to reduce their risk of the disease. This will be administered while they are in quarantine.  

19. Our current supply of JYNNEOS is projected to be sufficient based on the current vaccination strategy. We will continue to monitor the situation and adjust our vaccination strategy accordingly, as the mpox situation and vaccine supplies evolve globally.

About mpox

20. Mpox, caused by the monkeypox virus, has two subtypes, namely Clade I and Clade II. Clade II has been circulating globally as part of the 2022 multi-country outbreak. Since 2023, there has been an increase in the number of mpox Clade I cases reported by the Democratic Republic of the Congo (DRC). From July 2024, at least five¹ other countries in the region, including those where historically mpox Clade I was not endemic, have also reported mpox cases and outbreaks. Thus far, the outbreak remains generally confined to Africa, with two cases of the more severe mpox Clade I reported in Sweden and Thailand. There are currently no reports of local spread in these two countries.

21. The main symptom of mpox is rash. Other symptoms include fever, muscle aches, swollen lymph nodes and fatigue. The incubation period is typically between six and 16 days, and can be up to 21 days. Individuals are usually infectious from the time symptoms begin until all scabs have fallen off naturally. Mpox Clade I, which has a recorded case fatality rate of about 3% to 4% in the DRC, has been known to cause more severe disease than Clade II, but clinical outcomes may be different in countries outside of Africa.

22. Based on current evidence, mpox can be spread through close contact with respiratory tract secretions, skin lesions and bodily fluids of an infected person or animal, as well as recently contaminated objects or surfaces. In adults, mpox is transmitted primarily through close physical contact, including sexual contact, with infected individuals. In children, it is mainly spread through physical contact in households, playtime and exposure to wild game. More data is needed to determine the risk mpox poses to children, and MOH is monitoring this closely.

23. Compared to COVID-19, mpox is less infectious. Every person infected with mpox spreads the disease to an average of 1.3 other persons. Comparatively, without measures, each case of COVID-19 and its subsequent variants spreads to an average of two to five persons. 

Health Advisory

24. Exercising personal responsibility especially when symptomatic, and practising good personal hygiene, remain effective at reducing the risk of transmission of mpox in the general population. The precautionary measures that members of the public should take against mpox remain relevant for both Clade I and Clade II. Please refer to the MOH website for more information.

25. MOH will continue to monitor the situation closely and ensure that our preparedness and response measures are calibrated based on the prevailing public health risk.

[1] Countries that have reported mpox Clade I cases are Burundi, Cameroon, Central African Republic, Democratic Republic of the Congo, Gabon, Kenya, Republic of the Congo, Rwanda and Uganda

*As of 12 September 2024, paragraph 14 has been amended for factual accuracy.