Covid-19 Infection After Kidney Transplantation in Spain: Comparable Impact Throughout Six Epidemic Waves

ABSTRACT

BACKGROUND AND AIMS The successive COVID-19 epidemic waves have significantly influenced kidney transplantation (KT) programs. Contact protection together with vaccination are the principal protective tools for KT recipients. We reviewed the impact of COVID-19 infection in KT recipients throughout the different epidemic waves. METHOD Of 900 active KT recipients in our program, 160 (17.8%) have suffered COVID-19 infection during the six epidemic waves first (March–August 2020), second (September–December2020), third (January–March 2021), fourth (April–May 2021), fifth (June–September 2021) and sixth (October–December 2021, preliminary data). We compared the clinical evolution and the impact of vaccination. RESULTS Infected KT recipients were younger in the third and fourth waves (P  < 0.001). We observed a higher percentage of pneumonia and hospital admission in the first and fifth waves (P = 0.045, P = 0.016) (Table 1), without differences in ICU admission, and with the disappearance of asymptomatic cases after the third wave. The highest mortality was observed in KT recipients >65 years old infected within the first 6 months after KT (P = 0.006) and overall mortality was higher in the first wave (P = 0.033). Mortality in hospitalized KT recipients and those admitted in the ICU were similar along the 5 waves, without clear impact of vaccination (P = 0.251). On the 5 January 2022, we have already accumulated an incidence of COVID in KT of 3.1% (sixth wave, 77% with booster vaccination), similar to the first wave (3.8%), with 12.5% mortality, similar to second, third and fifth waves, in patients with outcome (53.3%). CONCLUSION The incidence of COVID-19 in KT recipients has been high in all the waves of the pandemic in Spain. Global mortality has diminished after the first wave, and the time until outcome has increased. The highest mortality occurs in the subgroup of old KT recipients early after KT. Vaccination has not significantly reduced the mortality in KT with Covid who require hospital or ICU admission.