SINGAPORE - Singapore has detected its first local cases of the new Omicron sub-variants that are driving a fresh increase in Covid-19 numbers all over the world.
On Sunday night (May 15), the Ministry of Health (MOH) said it found two cases of the BA.4 variant and one case of the BA.5 variant through active surveillance.
The cases were first detected via polymerase chain reaction tests and confirmed through whole genome sequencing.
All three were either asymptomatic or had mild symptoms, and did not require hospitalisation. They were fully vaccinated and had received their booster doses.
They self-isolated upon testing positive for Covid-19 and had not been exposed to vulnerable settings, MOH said in a statement.
"We will step up local surveillance efforts and continue monitoring the spread of BA.4 and BA.5 in Singapore," it added.
"While our society is now more resilient against the virus, everyone should to continue to play their part and remain vigilant to mitigate the spread of Covid-19."
It urged people to ensure they are up to date with recommended booster jabs and exercise caution in areas with many people, especially for those who are more likely to develop complications if they are infected.
BA.4 and BA.5 were first detected in South Africa early this year and are now the dominant variants there. This means they have overtaken the BA.1 and BA.2 strains, which drove the original Omicron outbreak - including in Singapore.
The new variants have mutations in the spike protein which make them more effective at evading the immune system and more transmissible, MOH said. They are considered variants of concern by the European Centre for Disease Prevention and Control.
"However, emerging real-world evidence from other countries supports that BA.4 and BA.5 infections will likely give rise to similar clinical outcomes, compared to previous Omicron lineages."
As at last Wednesday, at least 1,000 cases of BA.4 and BA.5 have been reported in at least 16 countries, according to the World Health Organisation.