The efficiency of COVID-19 vaccines among taiwanese patients with varied comorbidities

Background/Aims: The global pandemic of COVID-19 has caused tremendous loss of human life since 2019. Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the best policies to control the pandemic. The vaccination efficacy in Taiwanese patients with different comorbidities is elusive and to be explored. Method(s): Uninfected subjects who received 3-doses of mRNA vaccines (Moderna, BioNTech), non-replicating viral vector-based vaccines (AstraZeneca, AZ) or protein subunit vaccines (Medigen COVID-19 vaccine, MVC) were prospectively enrolled. SARSCoV2- IgG spike antibody level was determined (Abbott [SARS-CoV- 2 IgG II]) within 3 months after the last dose of vaccination. Charlson Comorbidity Index (CCI) was applied to disclose the association of vaccine titer and underlying comorbidities. Result(s): A total of 824 subjects were enrolled in the current study. The mean age was 58.9 years and males accounted for 48.7% of the population. The proportion of CCI with 0-1, 2-3 and>4 was 52.8% (n = 435), 31.3% (n = 258) and 15.9% (n = 131), respectively. The most commonly used vaccination combination was AZ-AZ-Moderna (39.2%), followed by Moderna-Moderna-Moderna (27.8%) and AZAZ- BioNTech (14.7%), respectively. The mean vaccination titer was 3.11 log BAU/mL after a median 48 days of the 3rd dose. Subjects of male gender, lower body mass index, chronic kidney disease, higher CCI, and receiving AZ-AZ based vaccination were likely to have a lower titer of antibody. There was a decreasing trend of antibody titer with the increase of CCT (trend P<0.001). Linear regression analysis revealed that AZ-AZ-based vaccination (beta: 0.341, 95% confidence intervals [CI]: 0.144, 0.21, P<0.001) and higher CCI (beta: - 0.055, CI: - 0.096, - 0.014, P = 0.009) independently correlated with low IgG spike antibody levels. Conclusion(s): Patients with more comorbidities had a poor response to 3 doses of COVID-19 vaccination. Further studies are warranted to clarify the efficacy of booster vaccination in the population. The vaccine titer did not differ between patient with or without chronic liver disease.

Triangular arbitrage across forex and cryptocurrency markets during the COVID-19 crisis: a MRS-AR approach

This article employs a Markovian regime-switching autoregressive approach to examine triangular arbitrage across forex and cryptocurrency markets during the coronavirus disease 2019 crisis. The findings suggest the following: (1) profitable triangular arbitrage tends to occur in the turbulent period during the crisis, significantly outperforming cryptocurrency investments;and (2) the persistent profitability of triangular arbitrage ensues from strong memory of high returns, low risk, and shock response to global quantitative monetary easing policy. Regulatory authorities should consolidate cryptocurrency supervision systems and establish cross-border coordination mechanisms to stabilize exchange rates and enhance market efficiency.