Association between history of HBV vaccine response and anti-SARS-CoV-2 spike antibody response to the BioNTech/Pfizer's BNT162b2 mRNA SARS-CoV-2 vaccine among healthcare workers in Japan: A prospective observational study.

INTRODUCTION: Inadequate vaccine response is a common concern among healthcare workers at the frontlines of the COVID-19 pandemic. We aimed to investigate if healthcare workers with history of weak immune response to HBV vaccination are more likely to have weak responses against the BioNTech/Pfizer's BNT162b2 mRNA SARS-CoV-2 vaccine. METHODS: We prospectively tested 954 healthcare workers for the Anti-SARS-CoV-2 spike (S) protein antibody titers prior to the first and second BNT162b2 vaccination doses and after four weeks after the second dose using Roche's Elecsys® assay. We calculated the percentage of patients who seroconverted after the first and second doses. We estimated the relative risk of non-seroconversion after the first BNT162b2 vaccine (defined as anti-SARS-CoV-2-S titer <15 U/mL) among HBV vaccine non-responders (HBs-Ab titer <10 mIU/mL) and weak responders (≥10 and <100 mIU/mL) compared to normal responders (≥100 mIU/mL). RESULTS: Among 954 healthcare workers recruited between March 9 and March 24, 2021 at Osaka Medical and Pharmaceutical University, weak and normal HBV vaccine responders had comparable S-protein titers after the first BNT162b2 dose (51.4 [95% confidence interval 25.2-137.0] versus 59.7 [29.8-138.0] U/mL, respectively). HBV vaccine non-responders were more likely than normal responders to not seroconvert after a single dose (age and sex-adjusted relative risk 1.85 95% confidence interval [1.10-3.13]) although nearly all participants seroconverted after the second dose. After limiting the analysis to 382 patients with baseline comorbidity data, the comorbidity-adjusted relative risk of non-seroconversion among HBV vaccine non-responders to normal responders was 1.32 (95% confidence interval [0.59-2.98]). DISCUSSION: Long term follow-up studies are needed to understand if protective immunity against SARS-CoV-2 wanes faster among those with history of HBV vaccine non-response and when booster doses are warranted for these healthcare workers.

Administration of a standard dose of vonoprazan fumarate delays gastric emptying in Japanese healthy adults: a prospective clinical trial.

BACKGROUND: There is no established view of how gastric acid suppression affects the time for gastric emptying. Vonoprazan fumarate shows potent and durable gastric acid inhibitory effects, but its effects on gastric emptying have not been studied widely. We investigated the effects of vonoprazan fumarate on gastric emptying and measured serum gastrin and plasma ghrelin levels in healthy adults. METHODS: Ten participants were administered 10 mg vonoprazan fumarate daily for 14 days, then 20 mg vonoprazan fumarate daily for 14 days. The gastric emptying breath test was performed and serum gastrin levels were measured at baseline and after each medication administration period. The protocol was then repeated, with the gastric emptying breath test and serum gastrin and plasma desacyl-ghrelin levels measured at baseline and the end of the medication trial. RESULTS: Mean serum gastrin levels increased in a dose-dependent manner [baseline: 104.7 ± 50.4, after 10 mg protocol: 328 ± 123.8, after 20 mg protocol: 555 ± 378.8 (pg/mL, mean ± standard deviation), p = 0.0008]. There was a significant difference between the gastric emptying breath test Tmax at baseline and just after the 20 mg protocol (baseline: 45.5 ± 15.3, after 20 mg protocol: 60.5 ± 19.6 min, p = 0.0418). Plasma desacyl-ghrelin levels increased significantly just after the 20 mg protocol compared to those at baseline [baseline: 222.3 ± 106.4, after 20 mg protocol: 366.2 ± 178.6 (fmol/mL), p = 0.0008]. CONCLUSIONS: In healthy adults, 14 days of vonoprazan fumarate administration at 20 mg/day delayed gastric emptying. TRIAL REGISTRATION: This clinical trial was registered in the University hospital Medical Information Network Clinical Trial Registry (Trial No. UMIN000039199 and UMIN000042969).

Evaluation of SARS-CoV-2 RNA quantification by RT-LAMP compared to RT-qPCR.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is a global pandemic caused by a novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The viral load of SARS-CoV-2 is associated with mortality in COVID-19 patients. Measurement of viral load requires the use of reverse transcription quantitative PCR (RT-qPCR), which in turn requires advanced equipment and techniques. In this study, we aimed to evaluate the viral load measurement using reverse transcription loop-mediated isothermal amplification (RT-LAMP), which is a simpler procedure compared to RT-qPCR. MATERIALS AND METHODS: RNA was extracted by using the QIAamp Viral RNA Mini Kit. The RT-LAMP assay was performed by using the Loopamp® 2019-SARS-CoV-2 detection reagent kit and 10-fold serial dilutions of known viral load RT-LAMP were used to measure Tt, which is the time until the turbidity exceeds the threshold. Based on the relationship between viral load and Tt, the linearity and detection sensitivity of the calibration curve were evaluated. In addition, 117 clinical specimens were measured, and RT-qPCR and RT-LAMP assay results were compared. RESULTS: The dilution linearity of the calibration curve was maintained at five orders of magnitude 1.0× 106 to 1.0 × 101 copies/µL, and was confirmed to be detectable down to 1.0 × 100 copies/µL. The limit of quantification of RNA extracted from clinical specimens using RT-LAMP correlated well with that obtained using RT-qPCR (r2 = 0.930). CONCLUSION: The findings indicate that RT-LAMP is an effective method to determine the viral load of SARS-CoV-2.