The protection against emerging SARS-CoV-2 variants by pre-existing antibodies elicited due to the current vaccination or natural infection is a global concern. We aimed to investigate the rate of SARS-CoV-2 infection and its clinical features among infection-naïve, infected, vaccinated, and post-infection-vaccinated individuals. A cohort was designed among icddr,b staff registered for COVID-19 testing by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). Reinfection cases were confirmed by whole-genome sequencing. From 19 March 2020 to 31 March 2021, 1644 (mean age, 38.4 years and 57% male) participants were enrolled; where 1080 (65.7%) were tested negative and added to the negative cohort. The positive cohort included 750 positive patients (564 from baseline and 186 from negative cohort follow-up), of whom 27.6% were hospitalized and 2.5% died. Among hospitalized patients, 45.9% had severe to critical disease and 42.5% required oxygen support. Hypertension and diabetes mellitus were found significantly higher among the hospitalised patients compared to out-patients; risk ratio 1.3 and 1.6 respectively. The risk of infection among positive cohort was 80.2% lower than negative cohort (95% CI 72.6–85.7%; p < 0.001). Genome sequences showed that genetically distinct SARS-CoV-2 strains were responsible for reinfections. Naturally infected populations were less likely to be reinfected by SARS-CoV-2 than the infection-naïve and vaccinated individuals. Although, reinfected individuals did not suffer severe disease, a remarkable proportion of naturally infected or vaccinated individuals were (re)-infected by the emerging variants.
【저자키워드】 SARS-CoV-2, viral infection, Epidemiology, 【초록키워드】 whole-genome sequencing, vaccination, Hospitalized, antibody, SARS-COV-2 infection, SARS-CoV-2 variant, Diabetes Mellitus, risk, oxygen, diabetes, hospitalized patients, hypertension, variants, Population, polymerase chain reaction, rRT-PCR, Cohort, COVID-19 testing, SARS-CoV-2 variants, male, age, Hospitalised patients, Follow-up, natural infection, clinical feature, Critical disease, Genome sequences, risk of infection, risk ratio, severe disease, reverse transcriptase, Chain Reaction, 1080, Post-infection, 95% CI, individual, sequence, naïve, Registered, participant, vaccinated individuals, oxygen support, positive, real-time reverse transcriptase-polymerase chain reaction, SARS-CoV-2 strain, vaccinated individual, responsible, tested, died, proportion, required, added, less, significantly higher, hospitalised patient, individuals, elicited, positive patient, Naturally, baseline, 【제목키워드】 COVID-19, Reinfection, vaccinated individual,