Anti-SARS-CoV-2 Seroconversion in COVID-19 Convalescent Kidney Transplant Recipients Compared With Non-Transplanted Patients: Results From a Brazilian Three Population Cohort Study

Background: Due to immunosuppression, kidney transplant recipients (KTRs) might have lower seroconversion prevalence after coronavirus disease 2019 (COVID-19) than non-transplanted patients. Thus, we aimed to evaluate the seroconversion rate after COVID-19 among KTRs compared to non-transplanted patients.Methods: This cohort study enrolled three non-paired groups of patients with COVID-19: 601 KTRs, 211 health care workers (HCWs), and 170 non-transplanted inhabitants (INHs) in a countryside city in Brazil. The anti-severe acute respiratory syndrome coronavirus 2 nucleocapsid antibody was assessed 14 days after diagnosis. The primary outcome was seroconversion.Findings: The KTRs were older, with more frequent comorbidities and severe COVID-19. Compared to those in HCWs and INHs, admission to the intensive care unit (ICU; 44.9% vs. 0% vs. 1.8%, p<0.001), mechanical ventilation requirement (32.3% vs. 0% vs. 1.8%, p<0.001), and death (28.8% vs. 0% vs. 1.2%, p<0.001) were significantly higher in KTRs. Seroconversion did not differ between the groups: 76.2% in KTRs, 74.9% in HCWs, and 82.2% in INHs (p=0.35). In a group-adjusted multivariable logistic regression, while a short period between infection and blood sample collection reduced the probability of seroconversion (adjusted odds ratio [aOR]=0.986), the presence of fever (aOR=1.737, p=0.017), cough (aOR=1.785, p=0.005), and requirement for ventilatory support (OR=1.981, p=0.017) increased the risk.Interpretation: The rates of clinical deterioration to ICU admission, mechanical ventilation requirement, and death were significantly higher among the KTRs. However, among the survivors, KTRs had a similar seroconversion prevalence associated with clinical severity parameters and a shorter time of blood sample collection.Funding Information: The study was funded by internal funding sources. There was no external funding evolved.Declaration of Interests: The authors had no competing interests to declare. Ethics Approval Statement: The study was approved by the local ethics committee (identification number CAAE 35321020.9.0000.8098, approval number 4.417.135). Informed consent was obtained or exempted following the guidelines of the Declaration of Helsinki, specific national legislation, and local institutional review board recommendations.