As the COVID-19 pandemic continues and the number of individuals with previous infectionrises, numbers of SARS-CoV-2 reinfection are increasing. The second Omicron wave inShanghai, China caused by BA.5-sublineages led to a large fraction of reinfections amongBA.2 primary infections. To better understand the SARS-CoV-2 reinfection rate andclinical severity of reinfections, the investigators conducted a multi-centre cohortstudy. The investigators hope to provide valuable clinical evidences for reinfections andoffer guidance for future policy making.
The investigators used data from Huashan Hospital, Renji Hospital, and Shanghai Jing' an
Central Hospital to collect information on SARS-CoV-2 primary infections with BA.2 during
1 March to 23 May 2022, and followed up for participants' reinfections with BA.5-lineages
during 1 December 2022 to 14 January 2023. After matched 1:1 by age and gender with the
reinfection cohort, data of primary infections with BA.5-sublineages were also collected.
Reinfection cases were defined as having positive COVID-19 PCR or antigen test, at least
90 days after participants' first positive testing. Basic information, vaccination
status, time interval between two infections, and clinical manifestations were collected.
Inclusion Criteria:
- All PCR- or RAT-confirmed SARS-CoV-2 reinfections were included in the study.
Exclusion Criteria:
- Patients who did not know if they were reinfected were excluded.
Huashan Hospital Affiliated to Fudan University
Shanghai, China
Jiming Zhang, PhD, Study Director
Huashan Hospital