Scientific Reports (Jan 2022)

COVID-19 reinfections among naturally infected and vaccinated individuals

  • Sezanur Rahman,
  • M. Mahfuzur Rahman,
  • Mojnu Miah,
  • Mst Noorjahan Begum,
  • Monira Sarmin,
  • Mustafa Mahfuz,
  • Mohammad Enayet Hossain,
  • Mohammed Ziaur Rahman,
  • Mohammod Jobayer Chisti,
  • Tahmeed Ahmed,
  • Shams El Arifeen,
  • Mustafizur Rahman

DOI
https://doi.org/10.1038/s41598-022-05325-5
Journal volume & issue
Vol. 12, no. 1
pp. 1 – 10

Abstract

Read online

Abstract 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.