Robust antibody response after the third mRNA coronavirus vaccination in Japanese hemodialysis patients

BackgroundHemodialysis patients have chronic kidney disease, are often elderly, and have many complications such as hypertension, type 2 diabetes, cardiac disease, and cerebrovascular disease. Therefore, hemodialysis patients infected with COVID-19 are prone to severe disease. Vaccination is the most promising means of preventing the onset and reducing the severity of COVID-19. However, many reports have found that anti-spike antibody titers after two doses of mRNA vaccine are lower in hemodialysis patients than in healthy controls. For this reason, a third vaccination is recommended for hemodialysis patients. In Japan, there are several reports of a third vaccination, especially for hemodialysis patients. In this study, we also examined the antibody response to COVID-19 vaccine in Japanese hemodialysis patients who received the third dose of the vaccine.MethodsStudy participants received a third vaccination (257 with BNT162b2 vaccine and 5 with mRNA-1273 vaccine) approximately 7-9 months after the second (BNT162b2 vaccine). Anti-SARS-CoV-2 spike IgG antibody titers were measured (Abbott SARS-CoV-2 IgG II Quan) in 185 hemodialysis patients and 109 healthcare workers approximately 2 weeks after the second vaccination and in 162 hemodialysis patients and 100 healthcare workers approximately 2 weeks after the third.ResultsFollowing the second vaccination, 97.6% of the hemodialysis group and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 2728.7 AU/mL (IQR, 1024.2-7688.2 AU/mL) in the hemodialysis group and 10,500 AU/ml (IQR, 9346.1-2,4500 AU/mL) in the controls. Following the third vaccination, 99.4% of the hemodialysis group (only one person tested negative for the antibody) and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 20,000 AU/mL (IQR, 7729-37,000 AU/mL) in the hemodialysis group and 21,500 AU/ml (IQR, 14,000-32,250 AU/mL) in the control group. The factors involved in the low response to the BNT152b2 vaccine after the second vaccination included old age, low BMI, low Cr index, low nPCR, low GNRI, low lymphocyte count, steroid administration, and complications related to blood disorders. However, in hemodialysis patients, the response after the third vaccination was excellent, and all factors associated with the suppressed response to these vaccines were no longer significant.ConclusionsThe humoral response of hemodialysis patients to two doses of mRNA vaccine was weaker than that of healthy controls. However, a third vaccination eliminated that difference.