Comparative outcomes of SARS-CoV-2 primary and reinfection in older adult patients

First infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with increased risk of acute and postacute death and sequelae in various organ systems. Whether reinfection adds to risks incurred after first infection is unclear. Here we used the US Department of Veterans Affairs’ national healthcare database to build a cohort of individuals with one SARS-CoV-2 infection ( n  = 443,588), reinfection (two or more infections, n  = 40,947) and a noninfected control ( n  = 5,334,729). We used inverse probability-weighted survival models to estimate risks and 6-month burdens of death, hospitalization and incident sequelae. Compared to no reinfection, reinfection contributed additional risks of death (hazard ratio (HR) = 2.17, 95% confidence intervals (CI) 1.93–2.45), hospitalization (HR = 3.32, 95% CI 3.13–3.51) and sequelae including pulmonary, cardiovascular, hematological, diabetes, gastrointestinal, kidney, mental health, musculoskeletal and neurological disorders. The risks were evident regardless of vaccination status. The risks were most pronounced in the acute phase but persisted in the postacute phase at 6 months. Compared to noninfected controls, cumulative risks and burdens of repeat infection increased according to the number of infections. Limitations included a cohort of mostly white males. The evidence shows that reinfection further increases risks of death, hospitalization and sequelae in multiple organ systems in the acute and postacute phase. Reducing overall burden of death and disease due to SARS-CoV-2 will require strategies for reinfection prevention. A new analysis using US Department of Veterans Affairs databases showed that reinfection is associated with increased risk of all-cause mortality, hospitalization and a wide range of long COVID complications in individuals who have had SARS-CoV-2 compared to those with no reinfection.

Objective We aimed to look at the burden of disease caused by SARS-COV-2 reinfections and identified potential risk factors for disease severity. Methods We used national surveillance data to collect information on all SARS-CoV-2 primary infection and suspected reinfection cases between January 2020 until early May 2021. Reinfection cases were positive COVID-19 PCR or antigen test, 90 days after their first COVID-19 positive test. We collected information on case demographics, hospital and ICU admission, immunisation status and if individuals were at risk of complication for COVID-19. Results Deaths reported within 28 days of testing positive were 61% (95% confidence interval: 56% to 65%) lower in suspected COVID-19 reinfection than primary infection cases. In the unvaccinated cohort, reinfections were associated with 49% (37% to 58%) lower odds of hospital admission in cases aged 50 to 65 years in the population not identified at risk of complication for COVID-19, and 34% (17% to 48%) in those at risk. ICU admission at reinfection compared to primary infection decreased 76% (55% to 87%). Individuals at risk and those aged below 50 years, who received at least 1 dose of vaccine against COVID-19, were 62% (39% to 74%) and 58% (24% to 77%) less likely to get admitted to hospital at reinfection, respectively. Conclusion Prior SARS-CoV-2 infection was associated with lower odds of dying, and both prior infection and immunisation showed a protective effect against severe disease in selected populations. Older age, sex and underlying comorbidities appeared as principal risk factors for illness severity at reinfection. Funding PHE/UKHSA

Several vaccine candidates have been developed using different platforms, including nucleic acids (DNA and RNA), viral vectors (replicating and non-replicating), virus-like particles, peptide-based, recombinant proteins, live attenuated, and inactivated virus modalities. Although many of these vaccines are undergoing pre-clinical trials, several large clinical trials investigating the clinical efficacy and safety of coronavirus disease 2019 (COVID-19) vaccines have produced promising findings.