SINGAPORE has not detected any cases of the more infectious Clade I variant of the mpox virus so far, the Ministry of Health (MOH) said on Wednesday (Sep 4).
All 14 confirmed cases of mpox detected here are of the “better understood and less severe” Clade II variant, said Dr Marc Ho, from MOH’s communicable diseases policy and preparedness division, at a press conference.
The Clade I variant remains generally confined to Africa for now, he said, and the risk of the virus being imported from outbreak countries is low as there are no direct flights between Singapore and Africa.
Clade I cases are expected to be spotted across the world, he noted. “But as long as these cases do not spread in their respective countries, the risk to Singapore does not change significantly.”
Minister for Health Ong Ye Kung said there is no need to raise the infectious disease alert level to that of a public health threat, which was the level during the Covid-19 pandemic. The level is currently at that of “outbreak management”, one step up from the baseline.
“We have been developing many contingency plans since the Covid-19 pandemic,” said Ong. “It’s time for us to dust off these plans and put some of them into action.”
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Singapore’s response measures may change as more is understood about the virus, he added.
Vaccine measures
Current measures include selective vaccination of two groups: healthcare workers with the highest risk of exposure, and close contacts of confirmed mpox cases. Both groups will be offered the Jynneos vaccine to reduce their risk of the disease.
In a media release, MOH said Singapore’s supply of the vaccine is “projected to be sufficient based on the current vaccine strategy”.
At the press conference, MOH director-general of health Kenneth Mak added that the health ministry is looking at procuring more doses when available. “We will continue to monitor the situation and adjust our vaccination strategy accordingly, as the mpox situation and vaccine supplies evolve globally.”
Yet, there is not an “infinite supply” of the vaccine, said Ong, adding that it would not be effective to offer it to everyone.
“You are somewhat wasting the vaccine, given that (the virus) has an (infectious rate) of 1.3,” he added. This means that every person infected with mpox spreads it to an average of 1.3 other persons. For Covid-19 and its variants, each case spreads it to another two to five people, without preventive measures.
The health ministry currently has no plans to offer the Jynneos vaccine to anyone else, said Prof Mak. It is also not recommending that travellers get vaccinated.
This is due to the current understanding that the disease is spread mainly through contact with the skin of infected cases or contaminated surfaces, he said. Airborne transmission, the predominant way in which Covid-19 spreads, “is a possibility, but as yet, not quantified”.
MOH added that there is “good evidence” that smallpox vaccination gives cross-protection against mpox. As this vaccine was required in Singapore until early 1981, a “significant segment” of the population – aged 45 and above – will have mpox immunity.
Screening measures
Singapore has put in place temperature and visual screening at airports for travellers and crew arriving from places where they may have been exposed to mpox Clade I outbreaks, as well as at sea checkpoints for those arriving on ships from mpox-affected areas.
Travellers are required to report mpox-related symptoms and travel history through the SG Arrival Card.
Medical practitioners and healthcare institutions are required to report any detected cases. Any confirmed Clade I mpox cases will be sent to hospitals, and MOH will start contact-tracing and isolate any close contacts in government quarantine facilities for 21 days.
Based on current evidence that mpox is spread mainly through close physical contact, MOH does not recommend wearing a mask for people who are well. But if there is evidence of significant respiratory transmission, it “will consider implementing masking” on public transport and in crowded indoor places.
