Blunted humoral immune response to the fourth dose of BNT162b2 COVID-19 vaccine in patients undergoing hemodialysis.

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.

SARS-CoV-2 spike protein antibody titers 6 months after SARS-CoV-2 mRNA vaccination among patients undergoing hemodialysis in Japan.

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.

Effect of oocyte transportation time on the clinical results of transport in vitro fertilization/intracytoplasmic sperm injection-embryo transfer.

Background and Aims: In transport assisted reproductive technology (ART), the time taken to transport oocytes to the main center differs greatly among the satellite facilities and may influence the clinical results. Methods: For the conventional in vitro fertilization (IVF) groups in which oocytes were collected at the satellite facilities and transported to the main ART center for insemination and embryo transfer, there were 29 cycles in 27 patients with a transportation time within 60 min (short time transport IVF (ST-IVF)), 78 cycles in 62 patients with a time between 60 and 120 min (long time transport IVF (LT-IVF)), and there were 141 cycles in 110 patients at the main ART center (center IVF (C-IVF)). For the intracytoplasmic sperm injection (ICSI) group, there were 65 ST-ICSI cycles in 42 patients, 146 LT-ICSI cycles in 97 patients, and 326 cycles in 238 patients at the main ART center (C-ICSI). Results: The morphologically favorable embryo rate was lower in the ST-ICSI group (33.8%, P < 0.05) than in the C-ICSI group (38.1%), and the morphologically poor embryo rate in the LT-IVF group (38.6%, P < 0.0001) was higher than in the C-IVF group (26.7%). The rate of embryo transfers resulting in pregnancies was 16.7% in the ST-ICSI group (P < 0.01) and 17.3% in the LT-ICSI group (P < 0.001), both less than that of 35.2% for the C-ICSI group. Conclusions: To improve both the morphologically favorable embryo rate and the pregnancy rate in transport ART, it is essential to improve the total quality control at the satellite facilities. (Reprod Med Biol 2004; 3: 123-131).