What was a marginal contributor to Singapore's COVID-19 situation has quickly become the source of the majority of infections: Of the 4,427 cases here, more than 2,600 can be traced to migrant worker dormitories.

A record 728 new cases were reported on Thursday (Apr 16), with 654 of those infected living at worker dormitories. The number of dormitories with infections has grown to more than 25.

The Health Ministry's charts show that the cases among work permit holders and dormitory residents began climbing from Apr 1 even as the number infected in the community flattened and imported cases fell to zero - there have been no imported cases in Singapore for a week. ​​​​​​​​​​​​​​

Before Apr 3, there were just 38 cases in worker dormitories. The number is now 2,689 - a 70-fold increase - and among work permit holders not living at dorms, 218 have been infected, according to the Ministry of Health's situation report on Thursday.

It took only 10 days for that figure to double to 2,000, and three days for it to top 3,000 as the number infected at the dormitories shot up. and another 3 days before passing 5000 mark.