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This study tracked the postadjustment infection rates and symptom trends within community settings. Conducted from May 2023 to May 2024 across four districts in Shenzhen, involving 3246 participants, over 80% had received at least one vaccine dose. Postpolicy adjustment witnessed three significant infection surges. Among the cohort, 63.7% reported only one Coronavirus disease 2019 (COVID-19) infection, 30.3% two infections, and 1.7% three infections, with 4.3% remaining uninfected throughout the follow-up. Older adults and those with lower IgG levels had increased reinfection risk. Notably, 3.8% (95% CI: 3.1-4.6) reported long COVID, with higher susceptibility in those with underlying conditions (adjusted odds ratio [AOR] = 3.73, 95% CI: 2.20-6.34) and reduced incidence among fully vaccinated individuals (AOR = 0.57, 95% CI: 0.36-0.90). The policy change led to widespread exposure, shifting from first infections to reinfections. These insights underscore the need for ongoing research to inform future pandemic responses.