SINGAPORE — On Monday (Dec 27), co-chair of the national Covid-19 task force, Mr Lawrence Wong, said that Singapore would now deal with Omicron cases the same way it does for the Delta variant given early international evidence showing that Omicron is more transmissible but causes less severe illness than Delta.

This means that those infected with the Omicron strain can isolate at home while border restrictions will be lifted for countries such as Botswana, Ghana and South Africa where the strain has spread widely, said the Ministry of Health in a press release on Sunday.

It was a turnaround from a month ago when the Omicron variant had only just emerged and the authorities imposed stricter border controls and isolated those confirmed or suspected to be infected with the variant at the National Centre for Infectious Diseases to keep Omicron cases under control in Singapore.

TODAY looks at how the Omicron strain differs from Delta, and whether Singapore’s latest approach towards Omicron cases means that the country can stay the course for re-opening.

HOW DIFFERENT IS OMICRON FROM DELTA?

Infectious diseases experts that TODAY approached said that the Omicron variant is significantly more transmissible than Delta.

Dr Ling Li Min, a senior consultant at Rophi Clinic, said that Omicron cases double every two to four days, shorter than the time taken for the Delta variant to double.

She cited a study by the United Kingdom’s Health Security Agency which showed that the Omicron strain is 3.2 times as likely as the Delta variant to transmit within a household.

However, preliminary studies have suggested that the Omicron variant causes less severe infection compared to the Delta strain.

Early research by scientists from the University of Edinburgh, for instance, found that those infected with Omicron were almost 60 per cent less likely to be hospitalised than people infected with Delta.

However, Dr Duane Gubler of the Duke-NUS Medical School said that current infections could appear to be less severe in patients because of the protection afforded by vaccines and prior Covid-19 infections in patients. He added that further studies are needed to assess the severity of Omicron.

Similarly, Dr Ling said that it is still early days as incidence of severe illness usually  occurs only weeks later.

DOES THE VACCINE WORK AGAINST OMICRON?

In a Facebook post on Monday, Mr Wong, who is also the Finance Minister, said that vaccines and boosters remain “a key strategy” against Omicron.

Associate Professor Ashley St John of the Duke-NUS Medical School said that there is a “strong indication” from other countries that vaccination is highly effective in preventing severe diseases caused by all known Covid-19 variants.

To limit vaccine breakthrough cases caused by Omicron, Assoc Prof St John said that booster jabs should be encouraged as they are known to further reduce the likelihood of severe infections and its symptoms.

Dr Francis Collins, the director of the National Institutes of Health, the US’ public health research agency, noted in a Dec 14 blog post that there appears to be a “significant decline” in neutralising antibodies against the Omicron strain in people who have received two doses of an mRNA vaccine as compared to its protection against the original variant.

“However, initial results of studies conducted both in the lab and in the real world show that people who get a booster shot, or third dose of vaccine, may be better protected,” he added.

He cited a study by vaccine manufacturer Pfizer which showed that a booster dose of the Pfizer-BioNTech vaccine raised antibody levels against Omicron to a level comparable to the two-dose regimen against the original strain of the coronavirus.

Backing this view, an analysis by the United Kingdom Health Security Agency showed a “significant drop-off” for two doses of the Pfizer-BioNTech vaccine, according to British broadcaster the BBC earlier this month.

While a booster shot offers 75 per cent protection against Covid-19 symptoms, this is not as high as for previous variants, reported the BBC.

SHOULD WE TREAT OMICRON LIKE DELTA?

Assoc Prof St John said that it is “reasonable” to treat Omicron with the same approach as Delta. This is because the Singapore population is highly vaccinated and it has been established that vaccination is “very effective” in preventing severe diseases caused by Omicron.

She added that the virus can be managed through the simultaneous use of other measures such as wearing a mask, testing and isolation of infectious people.

Dr Paul Tambyah, President of the Asia Pacific Society of Clinical Microbiology and Infection, called the latest approach by the Government “the right decision”.

He said that the authorities had realised quickly that it was not practical to have a zero-Omicron strategy and had switched to the original strategy of living with the virus following quick and reliable data on Omicron’s severity from South Africa and the United Kingdom.

CAN SINGAPORE REOPEN AS PLANNED?

With MOH saying on Sunday that it expects a new wave of local Covid-19 cases in the coming days and weeks given the higher transmissibility of Omicron, can Singapore ease restrictions and reopen as planned?

Infectious diseases experts say that it is possible to move towards living with Covid-19, but added that the authorities should continue to monitor hospitalisation rates.

Dr Dale Fisher, a senior infectious diseases consultant at the National University Hospital, said that with more information, Singapore is now “more confident” that Omicron will not threaten the country and restrictions can be eased.

He noted that Covid-19 cases requiring hospitalisation and treatment in the intensive care units are at their lowest in months and the current low levels of disease in Singapore combined with high vaccination rates supports the potential to accelerate the opening of the country.

“Reopening would see real social and economic benefits and a general morale boost to the whole community,” he added.

Associate Professor Hsu Li Yang from the National University of Singapore (NUS) Saw Swee Hock School of Public Health said that there is enough information on the Omicron strain to know that there is no reason to enact more restrictive measures compared to other variants.

Nevertheless, he warned that large numbers of healthcare or other essential workers might become infected by Omicron over the same period of time by contracting the virus through the community.

This might reduce healthcare capacity as well as impact the delivery of other essential services temporarily. 

He added that the authorities will probably have to wait and see the impact of an Omicron surge in Singapore over the next few weeks to confirm that the population is highly protected against the worst outcomes of the variant.