[2] With its relative success in curbing the early spread of the virus in Singapore, the term "circuit breaker" and its measures was subsequently adopted by other countries, particularly in Canada and the United Kingdom.

[5] On 24 March, the Multi-Ministry Task Force announced stricter measures to combat the spread of COVID-19, after a huge spike in cases originating from returning Singaporeans in the community.

[6] On 3 April 2020, Prime Minister Lee Hsien Loong announced a nationwide partial lockdown, known as a circuit breaker, to contain the spread of COVID-19 in Singapore.

[9] On 14 April, then-Minister for National Development Lawrence Wong announced that the wearing of masks became compulsory when not at home with immediate effect, with fines and prosecution for offenders who refuse to do so.

[10] After discovering that the unknown number of cases was greater than expected, Prime Minister Lee Hsien Loong announced on 21 April an extension of the circuit breaker to 1 June.

[12] On 21 April, the Ministry of Education brought forward the 4-week school holidays for all MOE Kindergartens, primary, secondary and Pre-University students, which are usually held in June, to May.

Scanning in/out using the TraceTogether-only SafeEntry (TT-only SE) either through the TraceTogether app or token was made mandatory for all Singaporeans and at all places such as cinemas, restaurants, workplaces, schools and shopping malls for contact tracing purposes.

Restrictions due to new Variants of Concern (Delta and Omicron) started on 8 May 2021 and ended on 29 March 2022, during which gatherings of more than five people were prohibited.