RESUMO
Background: Kidney transplant recipients (KT) are a vulnerable population with a risk of death after COVID-19 infection (COV-I) four times higher than in the general population. mRNA COVID-19 vaccines changed the prognosis. Although KT have an impaired immunological response to mRNA vaccines, in March 2021 we started a vaccination campaign. Method(s): Among 1611 KT, 72 (4.2%) had COV-I (positive molecular nasopharyngeal swab) between 31 October 2021 and 15 January 2022 (3rd outbreak). Fourty-one (57%) were male and 58 (80.5%) had a deceased donor transplant, median age was 52 (43-60) years, median transplant vintage 57 (27-159) months, median serum creatinine 1.37 (1.0-1.7) mg/dL. KT were on calcineurin inhibitors, prednisone, mycophenolate (MMF) and mTOR inhibitors in 93-87-79% and 5.6% respectively. At COV-I 43 KT had received 3 doses of Comirnaty (BNT162b2), 21 two and 4 one, 4 were not vaccinated. DELTA variant was present in 36. Treatment included: increase of the daily steroid dosage (69%), MMF withdrawal (70%) or halving (5%) and monoclonal antibodies: Ronapreve or Xevudy (32%). Nine delta positive KT were hospitalized for severe respiratory distress: 2 died (6.6%). Result(s): The variables associated with an increased risk for hospitalization were older age and dyspnea (p=0.023, p<0.0001 respectively). At multivariate analysis, dyspnea (p <0.0001) and MMF (p=0.003) were independently associated with the risk for hospitalization. Combination of the two variables increased the significance (p<0.0001). Comparing this series to the 82/1503 (5.4%) KT infected during the previous waves, hospitalization, mortality and cumulative mortality rates dropped from 45%, 29.3% and 13.4% to 30%, 6.6% and 2.7% respectively, main difference being the absence of vaccination in the first group. Conclusion(s): Vaccinations did not reduce the incidence of COV-I among KT but provided certain protection associated with a significantly better outcome.