Re-infection in COVID-19: Do we exaggerate our worries?

Eur J Clin Invest. 2022 Jun;52(6):e13767. doi: 10.1111/eci.13767. Epub 2022 Mar 25.


Background: Protective long-term immunity following coronavirus disease 2019 (COVID-19) is unclear. The study evaluated the relationship between the vaccination status and risk factors in the re-infection of patients with a diagnosis of COVID-19 who reported to the Public Health Management System in a province in south-eastern Turkey.

Methods: Patients with positive results for the severe acute respiratory syndrome coronavirus 2 by the real-time reverse transcription polymerase chain reaction (RT-PCR) test in respiratory samples were defined as confirmed cases. Reinfection was diagnosed in cases with COVID-19 real-time RT-PCR positivity, with or without COVID-19-like symptoms, in at least 90 days after the first infection/disease.

Results: A total of 58 811 patients with the diagnosis of COVID-19 from March 11, 2020, to August 31, 2021, were included in the study. Re-infection was detected in 421 (0.7%) of all patients. The mean age of the cases was 38.0±16.0 years, and 51% of them were female. Eight (2.0%) of the cases resulted in death due to re-infection. No hospitalization or mortality was observed in fully vaccinated patients. Additionally, none of the mortal cases had completed the vaccination schedule.

Conclusions: We are concerned that the re-infection rates and mortality may increase due to new variant strains. Vaccination is the greatest weapon against progression to critical illness in re-infections, even with existing mutations. Therefore, it is important for those without a full vaccination schedule to be vaccinated, even if they have been previously infected.

Keywords: COVID-19; SARS-CoV-2; coronavirus; re-infection; vaccination.

MeSH terms

  • Adult
  • COVID-19* / epidemiology
  • Female
  • Hospitalization
  • Humans
  • Male
  • Middle Aged
  • Reinfection / epidemiology
  • SARS-CoV-2
  • Vaccination
  • Young Adult