Timeline

Dec 27, 2019: Chinese mainland reports first local COVID-19 infections in Wuhan, Hubei province.

Jan 15, 2020: First version of COVID-19 prevention and control protocol released. (Six later editions, mainly targeting the original novel coronavirus strain and early mutations such as Alpha, published during this period)

May 11, 2021: Eighth version of protocol, targeting the Delta strain, released, highlighting the prevention of COVID-19 risk posed by cold chain imports, and stricter testing for quarantined groups.

Nov 11, 2021: World's first Omicron cases detected in specimens collected in South Africa.

Jan 8, 2022: First domestic Omicron infection reported in Tianjin.

March to early May 2022: Ninth version of protocol takes shape and is piloted in seven cities across China for a month. Dominant strains are Omicron BA.1 and BA.2.

June 28, 2022: Ninth version of protocol, targeting Omicron, released, shortening quarantine period for inbound travelers and close contacts from 14 to seven days, and giving uniform categorizations for areas at risk.

July and August 2022: Health authorities assess results of implementing ninth version nationwide as dominant strains shift to Omicron BA.5, BA.5.2 and BA.2.76.

Nov 10, 2022: Central leadership reiterates unswerving adherence to dynamic zero-COVID policy and discusses 20 measures aimed at making COVID-19 response more scientific, targeted and efficient.

Nov 11, 2022: Details of the 20 measures announced, including further cutting isolation period, no longer tracing secondary close contacts, and abolishing circuit breaker mechanism for inbound international flights.

Sources: National Health Commission, National Administration of Disease Prevention and Control