Although there are no direct flights from the affected countries, that is not to say that there will not be any cases of mpox here – so Singapore, doctors and travellers from Africa need to be on the alert. 

Mpox is currently rampant in the Democratic Republic of Congo (DRC), where it has infected 16,700 people and killed 570 in 2024. It has also spread to neighbouring countries. While Singapore will see cases – there were 19 cases reported in 2022 from end-June, when reporting became mandatory; 32 in 2023, including 20 locally transmitted cases; and 12 so far in 2024 – experts The Straits Times spoke to do not foresee mpox becoming a major issue here. 

Mpox is very different from Covid-19, which caused substantial disruptions for more than two years. While both can be transmitted through close contact, the similarities end there. 

The virus that causes Covid-19 spreads far more easily because it can remain suspended in the air.

“There is a less explosive spread with mpox and it’s potentially containable, unlike Covid-19,” said Professor Hsu Li Yang, an infectious diseases expert at the NUS Saw Swee Hock School of Public Health (SSHSPH). 

But he did say that the mpox virus can remain active on surfaces for at least two weeks.

While the WHO says mpox can be spread by talking face to face with an infected person or even breathing near the person, the vast majority of transmission is through sexual or close household contact.

That makes mpox similar to the sexually transmitted human immunodeficiency virus (HIV), which causes the acquired immunodeficiency syndrome (Aids). 

HIV also emerged from Africa. Because it was left unchecked in the early years, today there are more than 40 million people around the world with this disease.

But there is a key difference between HIV and mpox. 

“HIV/Aids is a chronic infection with a long incubation period. Before treatments were available, it was almost universally lethal,” said Professor Dale Fisher, a senior infectious diseases expert at the National University Hospital.

“Mpox is a self-limiting condition, where the vast majority of patients recover fully.” 

With Singapore’s limited connections to Africa, the immediate risk here is low, Prof Fisher added. 

So, if it’s a disease that doesn’t spread explosively, is self-limiting with a fairly low mortality rate, and is generally still largely confined to the African continent, why has the WHO declared it a PHEIC?

PHEIC is WHO’s highest level of warning, introduced in 2005 following the severe acute respiratory syndrome (Sars) pandemic. This is the eighth time WHO has issued a PHEIC. 

And it is the second time mpox has been declared a PHEIC. The first time was in July 2022, and the emergency was lifted in May 2023 when cases started to decline globally. 

The surge in 2024 is caused by a new clade – or group of related viruses – called Ib, which has spread rapidly from the DRC to its neighbouring countries.

This new clade is more infectious and has a higher mortality rate than clade II, which caused the outbreak in 2022, said Professor Roy Chan, a National Skin Centre senior consultant specialising in sexually transmitted infections. 

“Whilst we may think that the current epidemic is far away, we should remember the 2022 epidemic spread rapidly to Western Europe and the United States, and then to the rest of the world,” he noted.

Prof Hsu said: “While whether and when to declare a PHEIC is almost always contentious, it is clear that this earlier declaration might secure resources and support that could help prevent a pandemic on the same scale as (the mpox pandemic in) 2022-2023.”

Prof Fisher said that when there is a new clade that appears to be both more infectious and more virulent, it is natural for the WHO to be more conservative, such as by declaring the PHEIC. “Global spread is inevitable, so the current effort is to slow spread while we learn more and, as needed, ramp up our abilities to test, vaccinate and treat.”

Dr Borame Dickens of the SSHSPH, whose area of research includes infectious disease epidemiology, said that as there is still “large uncertainty in the nature of this clade” and there remains the risk of further geographical spread, it warrants close monitoring.

Her colleague, Dr Akira Endo, pointed out that the new clade has infected a larger proportion of young children in the DRC. He said: “This suggests a potentially larger role of non-sexual transmission than the previously globally circulating virus (clade IIb) – through household contact, for example.”

Unicef said on Aug 16 that children account for more than half the cases in the DRC in 2024, as well as the vast majority of deaths. “The evidence indicates that children, especially those malnourished or affected by other illnesses, are the most vulnerable to catching and dying from this strain of mpox.”

Children here do not face the same risk, since they are generally not malnourished.

Professor Paul Tambyah, president of the International Society for Infectious Diseases, said many experts in the society argued that the WHO stepped down too early when it ended the mpox PHEIC in 2023.

“The whole idea of a global pandemic response is that we take action whenever there is an emerging disease which threatens human health, and ensure that everyone is protected by available vaccines. We do not stop when things are under control in the rich world.”

He added: “Singapore has a very good public health response, which has contained the virus so far. The key elements include access to vaccination, which works post-exposure.”

Prof Chan said it is important to have easily available and fast laboratory testing and confirmation. Should a case be confirmed, there needs to be epidemiological investigation and contact tracing. Even before results are back, suspected cases should be rapidly isolated until proven negative.

Prof Hsu expressed confidence that “we should be well able to manage an outbreak within Singapore”.

The Straits Times