Explainer: Why is monkeypox spreading around the world and should Singapore be concerned?

SINGAPORE — Cases of monkeypox have been on the rise across the world, with a handful appearing in the United Kingdom over the last month, and new cases being reported in Australia, France, Italy and Sweden.

The United States also confirmed its first case on Wednesday (May 18) and there are 13 suspected cases in Canada.

This has caused alarm worldwide because the disease, which causes a distinctive bumpy rash among other symptoms, mainly occurs in west and central Africa and does not usually spread elsewhere in the world. 

However, infectious disease experts in Singapore told TODAY that the virus causing monkeypox is not a cause of concern here for now, and that the chances of widespread transmission is far lower than that of the Sars-CoV-2 coronavirus behind Covid-19. 

News agency BBC reported that since the first case of monkeypox was detected in the UK on May 7 from a patient who had travelled to Nigeria, there have been a total of 20 confirmed cases in the UK this month. 

There was one confirmed case in Sweden and one in Italy on Thursday, and on Friday, Australia reported its first case from a patient who had returned from Europe. 

Just what is this illness, why is it spreading farther now, and with the resumption of international travel during the Covid-19 pandemic, what should Singapore do to prevent an outbreak? TODAY speaks to several experts to find out more. 

WHAT IS MONKEYPOX? 

The World Health Organization (WHO) said that the monkeypox virus is typically transmitted from animals to humans, from animal hosts such as rodents and monkeys.

It was first identified in the late 1950s in monkeys, then found in humans in the 1970s in the Democratic Republic of Congo, WHO’s website stated.

An infected person may have symptoms that include fever, headaches, swellings, back pain, aching muscles and a general fatigue.

Once the fever stops, a bumpy rash may develop, often beginning on the face, then spreading to other parts of the body, most commonly the palms of the hands and soles of the feet.

The rash can be extremely itchy and it goes through different stages before finally forming a scab, which later falls off, but can cause scarring.

The infection usually clears up on its own with symptoms lasting between two and four weeks. 

Animal-to-human transmission of the virus can occur from direct contact such as through blood, bodily fluids or lesions of infected animals. 

Human-to-human transmission can happen from close contact with respiratory secretions such as mucus, skin lesions of an infected person or recently contaminated objects, WHO said. 

For transmissions via droplets from respiratory particles, there usually has to be prolonged face-to-face contact, and this puts health workers, household members and other close contacts of active cases at greater risk.

Outbreaks of human cases of monkeypox have been reported in 11 African countries since 1970. However, outbreaks have also occurred in various other countries, be they among animals or humans.

In 2003, there was a monkeypox outbreak in the US involving infected pet dogs.

In the late 2010s, the virus has also been detected in travellers who went from Nigeria to other countries — including Singapore in May 2019. 

The death rate for infected persons used to be 0 to 11 per cent, but in recent times, it has been around 3 to 6 per cent. 

Associate Professor Alex Cook said that this is higher than the death rate of Covid-19, but more developed countries such as Singapore should not be too concerned. 

The vice-dean of research at Saw Swee Hock School of Public Health added: "We would hope it should be lower in high-income countries with more healthcare resources."

WHY IS MONKEYPOX SPREADING TO MORE PLACES NOW?

Experts told TODAY that the spread of the virus has caught the world by surprise because it is not commonly spread among people.

However, new evidence does suggest that the virus is transmitted sexually between men who have consensual sex and this may explain why cases are spreading. 

Professor Dale Fisher, senior consultant at National University Hospital's division of infectious diseases, said that transmission of the virus is traditionally through animal-to-human contact, and that "human-to-human transmission is known to occur but is not common".

However, Dr Paul Tambyah, president of the Asia Pacific Society of Clinical Microbiology and Infection, said there is evidence that the disease is "no longer confined to animal-to-human transmission or to travellers", although the sample size has been small in these studies.

Based on the evidence so far, "there is a significant amount of human-to-human transmission in Europe also apparently among men who have sex with men", Dr Tambyah added.

This is the first time that the monkeypox virus has been associated with possible sexual transmission. 

Prof Fisher said that even though several monkeypox cases are being identified in this "male demographic", there could be a bias since sexual health clinics may be on higher alert than other settings based on the initial real-life counts.

"You are more likely to get diagnosed because doctors are really on the lookout for it," he said. "It’s a bias to consider when analysing figures." 

WHO stated on its website that close physical contact is a well-known risk factor for disease spread, but it is unclear at this time if the monkeypox virus can be passed specifically through sexual contact and that more studies are needed to better understand this risk.

Prof Fisher pointed out that there is also another aspect of the disease spread that is not understood yet: Infected persons who may not have severe symptoms and are still able to go about their lives, interacting with others and potentially spreading the virus further. 

Assoc Prof Cook said that measures to prevent disease spread will hinge closely on what is understood about how the virus is transmitted. 

"It is as yet unclear what the implications of that will be for infection control, though as more information is gathered, we get a better idea of what measures to take to prevent spread," he added. 

The experts also noted that the spread of monkeypox could have coincided with the reopening of travel worldwide as Covid-19 border controls eased. 

"It is almost certain that we will get one or more cases of monkeypox in Singapore given the rebound in international travel," Dr Tambyah said. 

WHAT DID SINGAPORE DO TO TACKLE PAST CASES? 

MOH said on its website that Singapore had one imported case of monkeypox infection in May 2019: A 38-year-old Nigerian who had arrived here and later tested positive for the virus. 

He had attended a wedding in Nigeria, where he may have consumed bush meat, which could be a source of transmission of monkeypox virus, MOH said. 

Based on the ministry’s investigations and contact tracing, 22 people were identified as close contacts of the patient and they were quarantined and monitored for 21 days from their date of exposure to the man. 

MOH said that the close contacts were also offered vaccinations, which can prevent the disease or reduce the severity of its symptoms, and those who develop symptoms would be treated at the National Centre for Infectious Diseases (NCID).

Eventually, none of these contacts were found to be infectious.

Responding to queries from TODAY on Saturday, an NCID spokesperson said that at that time, the infected patient was immediately admitted to its isolation facility. Despite the virus being a rarely found here, NCID had diagnosed the patient within the same day of his admission, by using a polymerase chain reaction test and studying the sample under an electron microscope. 

"For NCID, a crucial aspect of the efficient outbreak management is high level of preparedness and awareness, having the knowledge and technological capabilities, and expertise to detect and confirm previously unknown or rare pathogens," the spokesperson said. 

WHAT DOES THIS MEAN FOR SINGAPORE NOW? 

Responding to queries from TODAY on Saturday, MOH said that as of May 20, there had been no monkeypox cases detected in Singapore since the case in 2019.

"In view of the cases in Europe and North America, the Ministry of Health has alerted all medical practitioners to remain vigilant in detecting and reporting monkeypox cases," an MOH spokesman said. 

"We will continue to monitor the situation closely."

However, the experts and authorities said that should a monkeypox outbreak occur here, it would affect far fewer people than the Covid-19.

In 2019, when the imported monkeypox case was detected, the executive director of NCID said that the risk of community spread within Singapore is low because there had been "no evidence to date that human-to-human transmission alone can sustain monkeypox infections in the human population". 

At that time, each infected person transmits the infection to fewer than one other person on average, which means that the virus is much less infectious than the one causing the common flu.

Assoc Prof Cook said that should more research conclude that sexual transmission is the main mode of spread between humans, it would not be so worrying.

"If sexual transmission is the main route of spread, it should act as a 'brake' on the growth of any outbreak, because the number of contacts is much higher for respiratory pathogens than sexually transmitted ones, making contact tracing relatively easier.

"At the early stage of any outbreak, there is uncertainty on the nature of the epidemic, but so far, there is no cause for alarm," he added.

Detecting the illness at the borders would be the first line of defence. 

"We advise travellers to take necessary precautions including maintaining a high standard of personal hygiene, avoiding direct contact with skin lesions of infected living or dead persons or animals, and avoiding contact with wild animals and consumption of bush meat," said the MOH spokesman. 

"Returning travellers, especially from areas affected by monkeypox, should seek immediate medical attention if they develop any disease symptoms within three weeks of their return. They should also inform their doctor of their recent travel history."

Agreeing, Dr Fisher said: "For Singapore, I think we should be on the alert for cases at this stage, particularly in travellers with consistent features." Consistent features refer to typical symptoms that infected people may have, such as bumpy rashes on their face and hands for the monkeypox virus. 

And should the virus enter Singapore, the experts agreed that the Covid-19 prevention playbook would still be applicable.

"The approach will be to isolate them, trace their contacts and quarantine them," Assoc Prof Cook said. 

Agreeing, Dr Tambyah said: "Good surveillance and targeted ring vaccination like (Singapore) did in 2019 should work to contain the virus should it begin spreading in the community."

The NCID spokesman added that "several lessons" were learned over Covid-19 which can be applied to monkeypox and most infectious diseases.

This includes seeking treatment or staying at home if feeling unwell and reducing social contact, as well as putting on a mask and practising good hand hygiene. 

Dr Tambyah added that although there is no specific vaccine for monkeypox, a smallpox vaccine does offer some protection since the two viruses are related. 

In data presented by WHO, ​​​​​​vaccines that were used to eradicate smallpox are up to 85 per cent effective against monkeypox. 

BBC reported that the UK has been stocking up on smallpox vaccines to help guard against monkeypox. 

Smallpox was a contagious and deadly virus that was eradicated with the help of vaccinations, with no naturally occurring cases since 1977. 

Dr Tambyah said: "Older people have all been vaccinated against smallpox when they were children, so they are less likely to be infected by monkeypox should it start spreading widely."