SINGAPORE - All local and imported cases of Covid-19 last month which underwent genome-wide sequencing were found to have been infected with the Omicron variant.
The Ministry of Health (MOH) said on Thursday (May 19) that of the local cases, 99 per cent were the sub-variant BA.2 strain and its lineages, which include BA.2.12.1.
The remaining 1 per cent was the BA.1 sub-variant.
Of the imported cases, 98 per cent were the BA.2 sub-variant and its lineages, 1 per cent was the BA.1 sub-variant and its lineages, and 1 per cent from recombinant lineages which include XJ and XE.
The XJ and XE strains are hybrids of the original Omicron strain BA.1 and the BA.2 sub-variant.
Two imported cases last month were infected with the BA.4 strain.
On Sunday (May 15), MOH said that it had detected two local cases of the BA.4 sub-variant and one local case of the BA.5 sub-variant.
All three are the first community cases confirmed to have been infected with the BA.4 and BA.5 variants, which the European Centre for Disease Prevention and Control had recently described as variants of concern.
On Thursday, MOH reported 4,578 new cases of Covid-19, down from 6,442 the day before.
The number of hospitalisations stood at 302, with eight patients in intensive care and 49 requiring oxygen supplementation.
There were two deaths recorded.
The week-on-week infection ratio rose to 1.14, from 1.05 the day before.
The rate refers to the ratio of community cases for the past week over those of the week before. A rate of more than 1 shows the number of new weekly Covid-19 cases is increasing.