Coronavirus Disease 2019 Vaccination Booster Effectiveness Based on the 2022 Japanese Dialysis Registry

To evaluate the effectiveness of the third, fourth, and fifth booster doses (rolled out in December 2021, June 2022, and October 2022, respectively) of the coronavirus disease 2019 (COVID-19) vaccine in Japanese haemodialysis patients during the Omicron era.

We analysed the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) year-end survey data from 2021 to 2022, which included information on the number of vaccinations and the most recent vaccination and infection months. For each month of 2022, the COVID-19 infection and related mortality risks were calculated by vaccination status, followed by logistic regression analyses to estimate adjusted odds ratios (aORs).

Overall, 225 887 patients were analysed, including 13 440 (5.9%), 25 547 (11.3%), 64 242 (28.4%), and 122 658 (54.3%) with ≤ 2, 3, 4, and 5 doses at the end of 2022, respectively. The third dose was significantly correlated with a lower risk of COVID-19 infection in early 2022 (March: aOR 0.53 [0.43-0.64]; April: 0.77 [0.63-0.95]) but was associated with a higher risk during mid-2022, coinciding with the BA.1/2 to BA.5 transition (July: 1.65 [1.39-1.95]; August: 2.37 [2.06-2.71]). The third dose consistently correlated with reduced COVID-19-related mortality. The fourth and fifth doses correlated with lower infection risk and COVID-19-related mortality throughout the period.

Among Japanese haemodialysis patients, the third to fifth COVID-19 vaccine doses were associated with reduced infection risk (except in July and August for third doses) and mortality.