SINGAPORE - Four Covid-19 cases infected with the BQ.1 and BQ.1.1 variants have been detected in Singapore as at Oct 23.

All four were imported cases and none was hospitalised, said the Ministry of Health (MOH) on Tuesday, without specifying where the cases came from.

Observations from countries with these cases suggest that the BQ.1 and BQ.1.1 variants are possibly more transmissible than previous Omicron sub-lineages, but there is currently no evidence that they cause more severe illness, said MOH.

The Omicron subvariants BQ.1 and BQ.1.1 were first detected in July 2022 in Nigeria and have since been detected in more than 50 countries. They are sub-lineages of the Omicron variant BA.5.

While both currently comprise a small proportion of Covid-19 cases globally, the number of BQ.1 and BQ.1.1 cases has recently been rising in parts of Europe and North America.

The US Centres for Disease Control and Prevention on Oct 21 estimated that the two variants make up for 16.6 per cent of the total circulating coronavirus variants in the United States.

On the same day, the European Centre for Disease Prevention and Control also warned that the two variants may account for more than half the infections in Europe between mid-November and early December.

MOH said it is closely monitoring information about new strains and the prevalence of circulating variants in the local community. Updates will be provided should there be significant developments, said the ministry.