Fig. 2: Serosurvey scheme and vaccination profile of the surveyed population.

a The scheme of serosurvey was conducted before and after each epidemic wave, with the corresponding timing marked by dashed vertical lines. The SARS-CoV-2 viral loads detected in Guangzhou’s sewage (marked by purple line) and nationally reported SARS-CoV-2 positive percentage in influenza-like illnesses (ILIs) (sourced from https://www.chinacdc.cn/jkzt/crb/zl/szkb_11803/jszl_13141/202401/t20240110_271902.html, in Chinese) (marked by orange line) were plotted to show the epidemiological dynamics. b The cumulative percentage of 2nd and 3rd serosurvey population that had been vaccinated. A total of 1446 individuals with immunological backgrounds were included in the count. The vaccinated population is color-coded as follows: the first dose in orange, the second dose in green, the third dose in red, and the fourth dose in purple. c The overview of vaccination status among the surveyed subpopulations (n = 1408). Inactivated-virus vaccination (individuals received one to four doses of vaccination with the primary does being an inactivated-virus vaccine); unvaccinated (individuals who had not received any vaccination); others (those who had primarily received recombinant protein vaccine or adenovirus vaccine). A stacked column format on the right side of the panel showed the percentage of individuals with various vaccination statuses within each age group as of December 2023.