| Popis: |
In late 2022, China transitioned from a strict ‘zero-COVID’ policy to rapidly abandoning nearly all interventions and data reporting. This raised great concern about the presumably-rapid but undisclosed spread of the SARS-CoV-2 Omicron variant in a very large population of very low pre-existing immunity. A quantitative understanding of the epidemic dynamics of COVID-19 during this period is urgently needed. Here, by modeling a combination of case count and survey data, we show that Omicron spread extremely fast, at a rate of 0.42/day (95% CrI: [0.35, 0.51]/day) after the full exit from zero-COVID policies on Dec. 7, 2022. Consequently, we estimate that the vast majority of the population (97%, 95% CrI [95%, 99%]) was infected during December, with the nation-wide epidemic peaking on Dec. 23. Overall, our results highlight the extremely high transmissibility of the variant and the importance of proper design of intervention exit strategies to avoid large infection waves. |
