Possible scenarios	Applicable response phases	Border control	Public health measures
			Temperature screening in institutions	Social distancing	School closures	Contact tracing	Phone surveillance or quarantine	Antivirals	Vaccination
Green (negligible to low public health impact)
High virulence No or limited human‐to‐human transmission Disease mainly overseas	Alert with containment of imported cases	HAN	No	No	No	Yes, if imported cases	To implement depending on risk	Treatment of cases where necessary	No
Similar or lower virulence and transmissibility as seasonal influenza	Mitigation	No	Consider for implementation	No	No	No	No	Treatment of cases where necessary	Vaccination for high risk groups if available
Yellow (low to moderate public health impact)
High virulence but low transmissibility Disease mainly overseas	Alert with containment of imported cases	HAN HDC Temperature screening of inbound passengers	No	No	No	Yes, if imported cases	To implement depending on risk	Treatment of cases where necessary	Procure and offer vaccines when available
Local epidemic with low virulence but high transmissibility	Mitigation	HAN	Consider for implementation	No	No	No	No	Treatment of cases where necessary	Procure and offer vaccines when available
High virulence and transmissibility but vaccine available	Mitigation	HAN	No	No	No	No	No	Treatment of cases where necessary	Distribute vaccine to mitigate impact
Orange (moderate to high public health impact)
High virulence and transmissibility Disease mainly overseas	Alert	HAN HDC Temperature screening of inbound passengers	No	No	No	Yes, if imported cases	Quarantine	Treatment of cases, consider limited prophylaxis of personnel providing essential services	Procure and offer vaccines when available
High virulence and transmissibility Disease in Singapore	Containment	HAN HDC Temperature screening of inbound passengers	Yes, depending on risk	Yes, depending on risk	Yes, selective closure if cases or clusters detected in schools	Yes, as far as operationally feasible	Quarantine, as far as operationally feasible	Treatment of cases, consider limited prophylaxis of personnel providing essential services	Procure and offer vaccines when available
High virulence and transmissibility More cases in Singapore	Limited mitigation	HAN HDC Temperature screening of all passengers	Yes, depending on risk	Yes, depending on risk	Yes, selective closure if cases or clusters detected in schools	No	No	Treatment of cases, consider limited prophylaxis of personnel providing essential services	Procure and offer vaccines when available
Red (high public health impact, widespread local transmission)
High virulence and transmissibility Widespread transmission	Mitigation	Temperature screening of all passengers	Yes	Yes	Yes	No	No	Treatment of cases and prophylaxis of personnel providing essential services	Procure and offer vaccines when available

HAN = Health Advisory Notice; HDC = health declaration card.

Adapted from Singapore Ministry of Health pandemic readiness and response plan.3