Supplementary Material for: Immunogenicity and safety of the three-dose COVID-19 vaccine regimen in patients receiving renal replacement therapy: a systematic review and meta-analysis

Background
A three-dose regimen is the current standard for COVID-19 vaccination, but systematic data on immunogenicity and safety in CKD patients remains limited.

Objectives
We conducted a meta-analysis on the immunogenicity and safety of three-dose COVID-19 vaccination in patients on renal replacement therapy (RRT).

Methods
Systematic literature search in four electronic databases yielded twenty eligible studies (2117 patients, 94% received mRNA vaccines) for meta-analysis.

Results
The overall seropositivity rate of anti-SARS-CoV-2 was 74.2% (95% CI: 65.0%-83.4%) after three-dose COVID-19 vaccination. The seropositivity rate of anti-SARS-CoV-2 in kidney transplant recipients (KTRs) was 64.6% (95% CI: 58.7%-70.5%), and 43.5% (95% CI: 38.5%-48.6%) of non-responders after second dose became seropositive after third dose. The seropositivity rate of anti-SARS-CoV-2 was 92.9% (95% CI: 89.5%-96.2%) in dialysis patients, and 64.6% (95% CI: 46.8%-82.3%) of non-responders after second dose became seropositive after third dose. In KTRs, each year increase in transplant vintage was associated with 35.6% increase in anti-SARS-CoV-2 seropositivity (95% CI: 15.9%-55.4%, p=0.01). There were no serious adverse events attributed to vaccination in KTRs and the commonest local and systemic adverse events were injection site pain and fatigue respectively.