SINGAPORE - The rise in Covid-19 cases here in recent months could have been caused by more contagious variants of the coronavirus first found abroad.
As at May 31, a total of 940 local and imported infections have involved a variant of concern.
There are four such known variants here. The Delta variant, also known as B16172, forms the bulk of cases with variants in Singapore, at 550 patients, according to the Ministry of Health (MOH).
This variant is considered more easily transmitted from human to human, and fuelled the massive spread of the virus in India.
It was first picked up in India last October, but is believed to have made its way to Singapore only recently.
On May 4, MOH said in a press release that there were seven local cases infected with the Delta variant in Singapore.
Experts have said that the increased transmissibility of the variant means there is a possibility of a large outbreak happening whenever infected cases move about in the community.
Recent evidence from Britain has suggested that the Delta variant has a reproductive number of five to eight, which is much higher than that of the wild-type variant, the original virus that the world saw early last year, which had a reproductive number of two to three.
The reproductive number of a virus is the number of new infections generated by each case.
The other Covid-19 variants of concern here are the Alpha variant, or B117, first detected in Britain, with 204 cases here; the Beta variant, or B1351, first found in South Africa, with 177 cases here; and the Gamma variant, or P1, first detected in Brazil, with nine cases here.