Everything About the New XBB Omicron Subvariant That is Causing a Spike in COVID-19 Cases in S’pore


If you have been receiving WhatsApp messages about how the XBB strain of the coronavirus has been causing a rapid and large increase in cases of severe illness and deaths, the Ministry of Health (MOH) has a message for you:

Those rumours are (partially) false.

To combat this misinformation, the Ministry will be initiating the Protection from Online Falsehoods and Manipulation Act (POFMA).

Singapore’s Current COVID-19 Situation

As of Tuesday (11 Oct), there are 11 intensive care unit (ICU) cases and 50 patients that require oxygen supplementation, which is higher than the level of what was observed the past few months, said MOH.

At the peak of the Delta wave, there were 171 ICU cases and 308 cases that needed oxygen supplementation, while there were 54 ICU cases and 242 patients that required oxygen supplementation at the peak of the Omicron wave.

However, the current increase in hospitalised cases is normal for Singapore when you consider the overall increase in cases.

Secondly, it is true that there has been a large increase in cases due to the XBB strain.

Singapore reported 11,732 new COVID-19 cases on Tuesday, more than doubling the 4,719 recorded cases from Monday (10 Oct).

This is also the first time in more than two months that the daily caseload has exceeded 10,000.

Having said that, the XBB strain is not causing more severe illnesses.

Most of the infected are reported to experience mild symptoms, such as sore throat or slight fever.

What is the XBB Strain?

According to recent studies and variant tracks alike, the XBB strain, otherwise known as BA.2.10, is proving to be the most immune-evasive yet.

What this means is that it has a higher chance of infecting people, even if they have been vaccinated.

The XBB strain is a combination of mutations from two Omicron strains, which explains its enhanced transmissibility, ability to evade antibody protections, and the consistent mild symptoms experienced by patients.

Hence, experts are concerned that monoclonal antibody treatments may be less effective against the newer variants.

Most scientists concur that Strain XBB and Omicron BA.2.75.2 are the important variants to watch right now.


For Singapore, the XBB strain is quickly dominating the other subvariants—within three weeks, it has gone from zero infected cases to becoming over half of all the daily cases.

In the breakdown of COVID-19 cases by strain on Monday, the MOH stated that 55% of infections were from the XBB strain, while BA.5 took up 21% of the cases, and BA.2.75 accounted for 24%.

The new strain has also been detected in Bangladesh and Hong Kong.  

Generally speaking though, SARS-CoV-2 is mutating into a less deadly virus, but what is so worrisome about the virus is that it is mutating so quickly.

“It’s a bit like what we would expect to see over a couple years of flu, but crammed into about three months with SARS-CoV-2,” said Tom Peacock, a virologist at Imperial College.


At this point, there are so many variants and subvariants that even the researchers are having problems keeping up with the names.

Introduction of Bivalent Boosters

In order to cope with spikes in the daily caseload due to the new Omicron subvariants, the MOH will be rolling out the Moderna/Spikevax bivalent vaccine on 14 October.

The difference between ordinary booster shots and the bivalent vaccine is that it will target both the original COVID-19 virus and the Omicron variant.

“It therefore will provide better protection against the newer COVID-19 variants. It is proven to be safe and effective,” said the ministry.

The new bivalent vaccine will be available to those who have yet to achieve maximum protection, as well as those aged 50 years and above who have received their last dosage more than five months ago.


Those eligible can walk into any of the nine Joint Testing and Vaccination Centres to get their booster shots.

The centres are at Ang Mo Kio, Bukit Merah, Commonwealth, Jurong East, Kaki Bukit, Pasir Ris, Sengkang, Woodlands, and Yishun.

The current mRNA vaccines will also be replaced by these bivalent vaccines.

In the days that follow, the Health Ministry will be watching the XBB strain “very closely”. 

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