SINGAPORE - The highly contagious Omicron variant could completely replace the Delta variant in the next two months as the dominant Covid-19 strain in Singapore, infectious diseases expert Dale Fisher said on Tuesday (Jan 4).
Even as the country recorded 438 new Omicron cases on Tuesday, with the weekly infection growth rate going above one for the first time since Nov 12, he said that the number to focus on is that of serious cases rather than overall infection figures.
If too many people come down with severe illness, demand for hospital and intensive care unit beds will shoot up, and the healthcare system will risk being overwhelmed.
"If the predictions are correct, we can expect high numbers with a mild disease, but we can't be sure of this yet," said Professor Fisher, a senior consultant at the National University Hospital's infectious diseases division.
"Singapore needs to retain its balancing act of keeping the country safe while not stifling travel, social activities and economic activity unnecessarily. It is a constant challenge when there are unknowns appearing regularly."
The weekly infection growth rate refers to the ratio of community cases for the past week over the week before. A weekly infection growth rate that is more than one indicates that the number of new Covid-19 cases is increasing.
On Monday, Health Minister Ong Ye Kung said in an update on Singapore's Covid-19 situation that Omicron cases now account for 17 per cent of all infections here, and warned that an Omicron wave is "imminent".
The country saw its first local case almost a month ago, when a staff member at Changi Airport tested positive for the variant.
On Dec 21, it reported its first cluster, which was linked to a gym in Bukit Timah.
This level of transmission is not surprising, given how quickly Omicron has replaced other variants around the world, observed Associate Professor Hsu Li Yang, an infectious diseases expert at the National University of Singapore's Saw Swee Hock School of Public Health.
He added that Singapore is likely to report a sharp rise in cases over the next few weeks, although the relatively low Omicron-linked hospitalisation and death rates in countries with a similar demographic profile have been reassuring.
Early studies have suggested the new variant is more likely to cause reinfections than other strains.
It is also believed to be more transmissible, although it is associated with milder illness.
"The biggest concern for Singapore is that the Omicron variant will introduce another round of infections, even for people who were previously infected with Delta," noted Professor Teo Yik Ying, dean of the Saw Swee Hock School of Public Health.
Even though most of the Omicron infections are likely to be mild, some of those infected will still require hospital care, he said.
But the good news is that Singapore's Covid-19 restrictions - including its mask mandate and rules on social gatherings - will slow the spread of Omicron here, he added.
The country reported 842 new cases as at noon on Tuesday.
Of these, 438 were of the Omicron variant, with 91 local cases and the rest imported.
However, rising Omicron numbers do not mean people should let their guard down over the Delta variant, which will still be a concern in the coming months, said Associate Professor Ashley St John of Duke-NUS Medical School's emerging infectious diseases programme.
"Delta causes severe disease, so we need to not underestimate the potential severity of new cases, particularly in the unvaccinated or immune-compromised, given the high proportion of Delta cases in our community right now," she said.