#3738 kidney transplant recipients become less adherent to preventive measures after sars‑cov‑2 vaccination and after awareness of antibody response

Abstract Background and Aims Kidney transplant recipients (KTRs) were advised to tightly adhere to government recommendations to curb the spread of SARS-CoV-2 because of a high risk of morbidity and mortality and decreased immunogenicity after vaccination. The aim of this study was to analyze the change in adherence to preventive measures after vaccination and awareness of antibody response, and to evaluate the effectiveness of these measures. Method Questionnaires were sent to 3531 KTRs enrolled in the Dutch RECOVAC studies, retrospectively asking for adherence to nine preventive measures on a 5-point Likert scale before and after SARS-CoV-2 vaccination and after awareness of antibody response. Blood samples were collected 28 days after the second vaccination. Antibody response was categorized as non-responder (≤50 BAU/mL), low-responder (>50 ≤300 BAU/mL) or high-responder (>300 BAU/mL), and shared with participants as a correlate of protection. Adherence before and after vaccination were compared by the Wilcoxon signed rank sum test. Logistic regression analysis was performed to estimate the association between antibody response and adherence, and adherence on acquiring SARS-CoV-2 infection. Results In 2939 KTRs (83%) who completed the first questionnaire on adherence to preventive measures, adherence was higher before than after SARS-CoV-2 vaccination (4.56, IQR 4.11-4.78 and 4.22, IQR 3.67-4.67, p < .001) (Figure 1). Adherence after awareness of antibody response was analyzed in 2399 KTRs (82%) of whom also blood samples were available, containing 949 non-responders, 500 low-responders and 950 high-responders. Compared to non-responders, low- and high-responders reported lower adherence (Figure 2). Higher adherence was associated with lower infection rates before and after vaccination (OR 0.67 [0.51-0.91], p = 0.008 and OR 0.48 [0.28–0.86], p = 0.010). Conclusion To the best of our knowledge, we are the first to show that KTRs became less adherent to social isolation and other preventive measures after vaccination against COVID-19. Adherence decreased in KTRs who were aware of a subsequent antibody response compared to those without. Moreover, preventive measures in this vulnerable group are effective, regardless of vaccination status.