Background: The use of convalescent plasma (CP) has been considered for its immunological mechanisms that could benefit patients in moderate and severe stages of COVID-19. This study evaluated the safety and efficacy of the use of donor CP for COVID-19. Material and methods: A double-blind, randomized controlled clinical trial was conducted from May to October 2020. Thirty-nine participants with moderate (II) and severe (III) stages of COVID-19 confirmed by RT-PCR were included. The study randomization rate was set at 3:1. CPs were chosen for application with a neutralizing antibody titer of ≥1:32. Results: We observed a significantly lower 21-day post-transfusion mortality HR: 0.17 (95.0% CI [0.07–0.45, p < 0.001]) in the group receiving CP compared with the control group; protective units (PU) in the group receiving convalescent plasma after seven days were significantly higher (512 (32–16,384) vs. 96 (32–256), p = 0.01); the PAO₂/FIO₂ index showed a significant improvement in the group receiving CP (251.01 (109.4) vs. 109.2 (62.4), p < 0.001, in the control group). Conclusion: CP is safe and effective, as it decreased mortality in the CP group compared with the control group.

In SARS-CoV-2, there is an overactivation of the immune system that triggers systemic hyperinflammation that causes lung damage; therefore, the use of convalescent plasma (CP) has been considered for its immunological mechanisms that could benefit patients in moderate and severe stages of the disease. This study evaluated the safety and efficacy of the use of convalescent donor plasma for COVID-19 to reduce mortality in patients with SARS-CoV-2 stage II (moderate) and stage III (severe) disease.Material and methodsA double-blind, randomized controlled clinical trial was conducted from May 20 to December 10, 2020. Thirty-nine participants with moderate (II) and severe (III) stage COVID-19 confirmed by RT-PCR and tomography were included. The study randomization rate was set at 3:1. Convalescent plasmas were chosen for application with a neutralizing antibody titer of ≥ 1:32. Patient follow-up included assessment by Sequential Organ Failure Assessment (SOFA) score and use of the Oxygenation Index (PAO₂/FIO₂) index and monitoring of blood markers, such as C Reactive Protein (CRP), D-Dimer (DD), ferritin, IgG antibody titers against SARS-COV-2, and inflammatory cytokines at days three and seven post-treatment.ResultsWe observed a significantly lower 21-day post-transfusion mortality HR: 0.17 [95.0% CI 0.07-0.45, p<0.001] in the group receiving convalescent plasma compared to the control group; protective units (PU) in the group receiving convalescent plasma after seven days were significantly higher 512 (32-16384) vs 96 (32-256), p=0.01; the SOFA scale decreased to 3.7 ± 2.02 vs 7.1 ± 2.8, p<0.001 and the PAO₂/FIO₂ index showed a significant improvement in the group receiving convalescent plasma 251.01 ± 109.4 vs 109.2 ± 62.4, p<0.001, vs the control group. In terms of safety, no adverse events related to the transfusion of convalescent plasma were observed.ConclusionConvalescent plasma is safe and effective, as it decreases mortality in the convalescent plasma group compared to the control group.

The National Institute of Cardiology has previously used the CoaguChek^® XS Plus system (Roche Diagnostics International Ltd), comparing capillary blood prothrombin time/international normalized ratio (PT/INR) results with those obtained using BCS-XP/Thromborel (Siemens). We assessed the reliability of PT/INR results using the third-generation CoaguChek Pro II system, the CoaguChek XS Plus system, and cobas^® t 411 for citrated plasma analysis. Venous and capillary PT/INR were measured (N = 204). Spearman's correlation, Bland-Altman, and concordance analysis between methods were conducted. Spearman's correlation coefficients between venous/capillary INR were high for CoaguChek Pro II versus CoaguChek XS Plus ( r = 0.994), CoaguChek Pro II versus cobas t 411 ( r = 0.967), and CoaguChek XS Plus versus cobas t 411 ( r = 0.968). Good concordance was observed among capillary methods (concordance coefficient [κ] = 0.888) and remaining relationships ( P < .001 for all): cobas t 411 versus CoaguChek XS Plus (κ = 0.696) and cobas t 411 versus CoaguChek Pro II (κ = 0.684). In conclusion, good agreement was observed between CoaguChek Pro II, CoaguChek XS Plus, and cobas t 411.

Booster doses of the SARS-CoV-2 vaccine have been recommended to improve and prolong immunity, address waning immunity over time, and contribute to the control of the COVID-19 pandemic. A heterologous booster vaccine strategy may offer advantages over a homologous approach. To compare the immunogenicity of two doses of BNT162b2 mRNA COVID-19 vaccine with a ChAdOx1-S booster dose, immunoglobulin G (IgG) anti-spike (anti-S) and anti-nucleocapsid (anti-N) antibody titers (Ab) were compared over 1 year and post-booster vaccination. Results showed that, at 3- to 9-month assessments in vaccinated subjects, an-ti-N Ab were undetectable in participants with no history of COVID-19. In contrast, anti-S Ab measurements were lower than those with COVID-19, and a decrease was observed during the 9 months of observation. After booster vaccination, no differences were found in anti-S between participants who reported a history of COVID-19 and those who did not. Anti-S levels were higher after booster vaccination measurement vs. at 9 months in participants with COVID-19 and without COVID-19, i.e., independent of an infection history. Vaccine administration elicited a response of higher anti-S IgG levels in those infected before vaccination, although levels decreased during the first nine months. IgG anti-N titers were higher in participants with a history of declared infection and who were asymptomatic. The ChAdOx1-S booster increased anti-S Ab levels in participants regardless of whether they had been infected or not to a significantly higher value than with the first two vaccines. These findings underscore the importance of booster vaccination in eliciting a robust and sustained immune response against COVID-19, regardless of the prior infection status.

Background/Objectives: There is wide variability in the individual response to clopidogrel, which depends on CYP2C19 polymorphisms as well as on intrinsic and extrinsic platelet factors. Clopidogrel resistance has been related to an adverse evolution in patients with coronary artery disease. The aim of this study is to analyze the prevalence of CYP2C19 polymorphisms in Mexican mestizo patients and their relationship with clopidogrel platelet response by means of platelet aggregation. Methods: Patients who experienced coronary artery disease (CAD) (N = 160) or stroke (N = 11) and received treatment with clopidogrel were analyzed for CYP2C19 alleles *1, *2, *3, and *17. In total, 81 patients were tested for clopidogrel resistance by ADP-induced aggregation in platelet-rich plasma. CYP2C19 polymorphism was expressed as ultrarapid-, normal-, rapid-, normal/intermediate, intermediate, and poor metabolizers, and the clopidogrel response was assessed by platelet aggregation. Results: The allelic frequencies were 9.6%, 0%, and 11.7% for CYP2C19*2, *3, and *17, respectively. The frequencies of CYP2C19 genotypes were as follows: CYP2C19*1/*1 (62.6%); CYP2C19*1/*17 (19.9%); CYP2C19*1/*2 (12.3%); CYP2C19*2/*17 (2.3%); CYP2C19*2/*2 (2.3%); and CYP2C19*17/*17 (0.6%). Of 81 patients with platelet aggregation, 55.6% were responsive, and 44.4% were resistant to clopidogrel. Clopidogrel resistance had a non-significant trend of association with unfavorable genotypes for metabolism (CYP2C19 *1/*2, *2/*17, and *2/*2) vs. favorable genotypes (CYP2C19 *1/*1, *1/*17, and *17/*17), 64.7% vs. 39.1%, respectively (p = 0.059). Conclusions: The prevalence of CYP2C19 polymorphisms in Mexican mestizo patients is similar to that of the general population. Clopidogrel resistance is a complex in vitro phenomenon that is not explained by CYP2C19 polymorphisms alone.