The Associated Factors of SARS-CoV-2 Reinfection by Omicron Variant — Guangdong Province, China, December 2022 to January 2023
C.S. Cai, Guangdong Field Epidemiology Training Program, Guangzhou City, Guangdong Province, China, Yihong Li, Ting Hu, Rongwei Liang, Kaibin Wang, Congrui Guo, Yan Li, Meng Zhang, Min Kang
Abstract
What is already known about this topic?: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection by variants is being reported commonly and has caused waves of epidemic in many countries. Because of dynamic zero policy, the SARS-CoV-2 reinfection was less reported in China. What is added by this report?: SARS-CoV-2 reinfections were observed in Guangdong Province between December 2022 and January 2023. This study estimated that the reinfection incidence was 50.0% for the original strain primary infections, 35.2% for the Alpha or Delta variants, and 18.4% for the Omicron variant; The reinfection incidence within 3-6 months after primary infection by Omicron variant was 4.0%. Besides, 96.2% reinfection cases were symptomatic while only 7.7% sought medical attention. What are the implications for public health practice?: These findings suggest a reduced likelihood of an Omicron-driven epidemic resurgence in the short term but emphasize the importance of maintaining vigilant surveillance of emerging SARS-CoV-2 variants and conducting population-based antibody level surveys to inform response preparedness.