Study on SARS-CoV-2 Reinfection Risks

The study, titled “Acute and postacute sequelae associated with SARS-CoV-2 reinfection” used the U.S. Department of Veterans Affairs’ healthcare database. It included 443,588 individuals with one COVID-19 infection, 40,947 with reinfections, and a control group of 5,334,729 non-infected individuals​​.

Key Findings

  • Increased Risks with Reinfection: Reinfection with SARS-CoV-2 significantly increased risks of all-cause mortality, hospitalization, and various sequelae affecting pulmonary, cardiovascular, hematological, gastrointestinal, kidney, mental health, musculoskeletal, and neurological systems​​.
  • Risk Persistence: The elevated risks were most pronounced in the acute phase but persisted into the postacute phase, up to 6 months post-reinfection​​.
  • Cumulative Risk: The study found a graded increase in health risks correlating with the number of infections. Individuals with multiple infections exhibited higher risks of sequelae compared to those with a single infection or non-infected controls​​.
  • Vaccination Status: Increased risks were observed irrespective of vaccination status before reinfection​​.


  • Clinical Consequences of Reinfection: The findings highlight the significant health impacts of SARS-CoV-2 reinfection, emphasizing the need for strategies to prevent reinfection.
  • Public Health Policy: With the ongoing mutation of the virus and the occurrence of reinfections globally, the study underscores the necessity for robust vaccination strategies and other interventions to mitigate the risk and adverse effects of reinfection​​.

Study Limitations

  • Potential Misclassification: The study might not include individuals who were infected but not tested, potentially underestimating the risks of reinfection.
  • Data Limitations: The Veterans Affairs cohort, predominantly older males, might not represent the general population. The study did not assess the severity of second infections versus first nor did it compare risks associated with different variants.
  • Dynamic Nature of the Pandemic: The evolving epidemiology of COVID-19, including new variants and changing vaccine immunity, could influence the reinfection risks and consequences​​.


The study provides compelling evidence that SARS-CoV-2 reinfection carries additional health risks, including increased mortality and a broad range of sequelae, reinforcing the importance of infection and reinfection prevention in public health policy.

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