Implementation and Cancellation of the Dynamic Zero-COVID Policy Led to a Steep Transient Peak in the First COVID-19 Surge in Beijing Dominated by a Nonprevalent SARS-CoV-2 Variant

This study tried to reveal how the implementation and cancellation of the dynamic zero-COVID policy could affect the development of the epidemic through wastewater surveillance of SARS-CoV-2 in Beijing during its first COVID-19 surge. A total of 443 24 h composite wastewater samples were taken from seven manholes and 10 wastewater treatment plants immediately on December 7, 2022, when the new COVID-19 policy was implemented, for the detection of SARS-CoV-2. The results showed that the first COVID-19 surge in Beijing was characterized by a rapid outbreak, short duration (one month), and extremely high infection rate (92.8%). Wastewater tiling amplicon sequencing showed that the main subvariant for this surge was BF.7.14 (65%), which has never caused an outbreak in other countries in the world. The variant BF.7.14 appeared in Beijing on August 15, 2022, as an imported case and then managed to retain and become a dominant variant as the strict dynamic zero policy had blocked the entry of other more infectious SARS-CoV-2 variants. This is the first study to capture the unique picture of the epidemic development in Beijing during its first COVID-19 surge, demonstrating that the strict dynamic zero-COVID strategy could shape the infection patterns greatly.