ABSTRACT
BACKGROUND: We aimed to investigate the impact of a fourth dose of BNT162b2 vaccine (Comirnaty®, Pfizer-BioNTech) on anti-SARS-CoV-2 (anti-S IgG) antibody titers in patients receiving hemodialysis (HD) and healthcare workers (HCWs). METHODS: A multi-institutional retrospective study at five dialysis clinics in Japan was conducted using 238 HD patients and 58 HCW controls who received four doses of the BNT162b2 mRNA vaccine. Anti-S IgG titers were measured at 1, 3, and 6 months after the second dose, at 1 and 5/6 months after the third dose, and at 1 month after the fourth dose of vaccine. RESULTS: The log anti-S IgG titers of the HD patients after the second vaccination were significantly lower than those of the control group, but equalized 1 month after the third vaccination: 9.94 (95% CI 9.82-10.10) vs. 9.81 (95% CI 9.66-9.96), (P = 0.32). In both groups, the fold-increase in anti-S IgG titers was significantly lower after the fourth dose than after the third dose of vaccine. In addition, there was a strong negative correlation between antibody titers 1 month after the fourth vaccination and antibody titers immediately before the vaccination. In both groups, the waning rate of anti-S IgG titers from the post-vaccination peak level after the third vaccine dose was significantly slower than that after the second dose. CONCLUSIONS: These findings suggest that the humoral immune response was blunted after the fourth dose of the conventional BNT162b2 vaccine. However, multiple vaccinations could extend the window of humoral immune protection.
Subject(s)
COVID-19 , Immunity, Humoral , Humans , BNT162 Vaccine , COVID-19 Vaccines , Retrospective Studies , COVID-19/prevention & control , Renal Dialysis , Immunoglobulin G , Vaccination , Antibodies, ViralABSTRACT
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is shown to prevent severe illness and death in hemodialysis (HD) patients, but the immune response to vaccines is reduced in this population. This study compared SARS-CoV-2 spike protein antibody titers between HD patients and healthy controls in Japan for up to 6 months following vaccination. METHODS: A multi-institutional retrospective study at five clinics in Japan was conducted using 412 HD patients and 156 healthy controls who received two doses of the BNT162b2 (Pfizer-BioNTech) mRNA vaccine. Anti-SARS-CoV-2 spike protein S1 IgG antibody titers were measured at 1, 3, and 6 months after the second dose. The attenuation speed was calculated as slope (i.e., -ß) using a linear mixed-effects model toward the log-transformed antibody titers. RESULTS: The HD group had significantly lower month 1 antibody titers (Ab-titer-1) than the controls, and these remained lower through month 6 (95% CI: 2617.1 (1296.7, 5240.8) vs. 7285.4 (4403.9, 11,000.0) AU/mL at Ab-titer-1, and 353.4 (178.4, 656.3) vs. 812.0 (498.3, 1342.7) AU/mL at Ab-titer-6 (p < 0.001, respectively)). Lower log Ab-titer-1 levels in the HD group were significantly associated with a lower log Ab-titer-6 (0.90 [0.83, 0.97], p < 0.001). The -ß values in the HD patients and healthy controls were -4.7 ± 1.1 and -4.7 ± 1.4 (year-1), respectively. CONCLUSION: SARS-CoV-2 spike protein antibody titers were significantly lower in HD patients than in healthy controls at 1 (peak) and 6 months after the second vaccination. Low peak antibody titers contributed to low 6-month antibody titers.
Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Antibodies, Viral , BNT162 Vaccine , COVID-19/prevention & control , Humans , Immunoglobulin G , Japan , RNA, Messenger , Renal Dialysis , Retrospective Studies , SARS-CoV-2 , Vaccination , Vaccines, Synthetic , mRNA VaccinesABSTRACT
We examined whether post-exercise yogurt intake reduced cardiovascular strain during outdoor interval walking training (IWT) in older people during midsummer. The IWT is a training regimen repeating slow and fast walking at ~40% and ≥70% peak aerobic capacity, respectively, for 3 min each per set, ≥5 sets per day, and ≥4 days/wk. We randomly divided 28 male and 75 female older people (~73 yr), who had performed IWT ≥12 months, into a carbohydrate group (CHO-G) consuming jelly (45 g CHO, 180 kcal) and a yogurt group (YGT-G) consuming a yogurt drink (9.3 g protein, 39 g CHO, 192 kcal) immediately after daily IWT for 56 days while monitoring exercise intensity and heart rate (HR) with portable devices. We analyzed the results in 39 subjects for the CHO-G and 37 subjects for the YGT-G who performed IWT ≥ 4 days/wk, ≥60 min total fast walking/wk, and ≥4 sets of each walk/day. We found that the mean HR for fast walking decreased significantly from the baseline after the 30th day in the YGT-G (p < 0.03), but not in the CHO-G (p = 1.00). There were no significant differences in training achievements between the groups. Thus, post-exercise yogurt intake might reduce cardiovascular strain during outdoor walking training in older people.