Reduced Immune Response to Inactivated Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine in a Cohort of Immunocompromised Patients in Chile.

BACKGROUND: Inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines have been widely implemented in low- and middle-income countries. However, immunogenicity in immunocompromised patients has not been established. Herein, we aimed to evaluate immune response to CoronaVac vaccine in these patients. METHODS: This prospective cohort study included 193 participants with 5 different immunocompromising conditions and 67 controls, receiving 2 doses of CoronaVac 8-12 weeks before enrollment. The study was conducted between May and August 2021, at Red de Salud UC-CHRISTUS, Santiago, Chile. Neutralizing antibody (NAb) positivity, total anti-SARS-CoV-2 immunoglobulin G antibody (TAb) concentrations, and T-cell responses were determined. RESULTS: NAb positivity and median neutralizing activity were 83.1% and 51.2% for the control group versus 20.6% and 5.7% (both P < .001) in the solid organ transplant group, 41.5% and 19.2% (both P < .0001) in the autoimmune rheumatic diseases group, 43.3% (P < .001) and 21.4% (P<.01 or P = .001) in the cancer with solid tumors group, 45.5% and 28.7% (both P < .001) in the human immunodeficiency virus (HIV) infection group, 64.3% and 56.6% (both differences not significant) in the hematopoietic stem cell transplant group, respectively. TAb seropositivity was also lower for the solid organ transplant (20.6%; P < .0001), rheumatic diseases (61%; P < .001), and HIV groups (70.9%; P = .003), compared with the control group (92.3%). On the other hand, the number of interferon γ spot-forming T cells specific for SARS-CoV-2 tended to be lower in all immunocompromising conditions but did not differ significantly between groups. CONCLUSIONS: Diverse immunocompromising conditions markedly reduce the humoral response to CoronaVac vaccine. These findings suggest that a boosting vaccination strategy should be considered in these vulnerable patients. CLINICAL TRIALS REGISTRATION: NCT04888793.

Early versus deferred anti-SARS-CoV-2 convalescent plasma in patients admitted for COVID-19: A randomized phase II clinical trial.

BACKGROUND: Convalescent plasma (CP), despite limited evidence on its efficacy, is being widely used as a compassionate therapy for hospitalized patients with COVID-19. We aimed to evaluate the efficacy and safety of early CP therapy in COVID-19 progression. METHODS AND FINDINGS: The study was an open-label, single-center randomized clinical trial performed in an academic medical center in Santiago, Chile, from May 10, 2020, to July 18, 2020, with final follow-up until August 17, 2020. The trial included patients hospitalized within the first 7 days of COVID-19 symptom onset, presenting risk factors for illness progression and not on mechanical ventilation. The intervention consisted of immediate CP (early plasma group) versus no CP unless developing prespecified criteria of deterioration (deferred plasma group). Additional standard treatment was allowed in both arms. The primary outcome was a composite of mechanical ventilation, hospitalization for >14 days, or death. The key secondary outcomes included time to respiratory failure, days of mechanical ventilation, hospital length of stay, mortality at 30 days, and SARS-CoV-2 real-time PCR clearance rate. Of 58 randomized patients (mean age, 65.8 years; 50% male), 57 (98.3%) completed the trial. A total of 13 (43.3%) participants from the deferred group received plasma based on clinical aggravation. We failed to find benefit in the primary outcome (32.1% versus 33.3%, odds ratio [OR] 0.95, 95% CI 0.32-2.84, p > 0.999) in the early versus deferred CP group. The in-hospital mortality rate was 17.9% versus 6.7% (OR 3.04, 95% CI 0.54-17.17 p = 0.246), mechanical ventilation 17.9% versus 6.7% (OR 3.04, 95% CI 0.54-17.17, p = 0.246), and prolonged hospitalization 21.4% versus 30.0% (OR 0.64, 95% CI, 0.19-2.10, p = 0.554) in the early versus deferred CP group, respectively. The viral clearance rate on day 3 (26% versus 8%, p = 0.204) and day 7 (38% versus 19%, p = 0.374) did not differ between groups. Two patients experienced serious adverse events within 6 hours after plasma transfusion. The main limitation of this study is the lack of statistical power to detect a smaller but clinically relevant therapeutic effect of CP, as well as not having confirmed neutralizing antibodies in donor before plasma infusion. CONCLUSIONS: In the present study, we failed to find evidence of benefit in mortality, length of hospitalization, or mechanical ventilation requirement by immediate addition of CP therapy in the early stages of COVID-19 compared to its use only in case of patient deterioration. TRIAL REGISTRATION: NCT04375098.

Influence of SARS-CoV-2 mRNA Vaccine Booster among Cancer Patients on Active Treatment Previously Immunized with Inactivated versus mRNA Vaccines: A Prospective Cohort Study.

Cancer patients on chemotherapy have a lower immune response to SARS-CoV-2 vaccines. Therefore, through a prospective cohort study of patients with solid tumors receiving chemotherapy, we aimed to determine the immunogenicity of an mRNA vaccine booster (BNT162b2) among patients previously immunized with an inactivated (CoronaVac) or homologous (BNT162b2) SARS-CoV-2 vaccine. The primary outcome was the proportion of patients with anti-SARS-CoV-2 neutralizing antibody (NAb) seropositivity at 8-12 weeks post-booster. The secondary end points included IgG antibody (TAb) seropositivity and specific T-cell responses. A total of 109 patients were included. Eighty-four (77%) had heterologous vaccine schedules (two doses of CoronaVac followed by the BNT162b2 booster) and twenty-five had (23%) homologous vaccine schedules (three doses of BNT162b2). IgG antibody positivity for the homologous and heterologous regimen were 100% and 96% (p = 0.338), whereas NAb positivity reached 100% and 92% (p = 0.13), respectively. Absolute NAb positivity and Tab levels were associated with the homologous schedule (with a beta coefficient of 0.26 with p = 0.027 and a geometric mean ratio 1.41 with p = 0.044, respectively). Both the homologous and heterologous vaccine regimens elicited a strong humoral and cellular response after the BNT162b2 booster. The homologous regimen was associated with higher NAb positivity and Tab levels after adjusting for relevant covariates.

Clinical characteristics and outcomes of people living with HIV hospitalized with COVID-19: a nationwide experience.

In this prospective, multicentric, observational study, we describe the clinical characteristics and outcomes of people living with HIV (PLHIV) requiring hospitalization due to COVID-19 in Chile and compare them with Chilean general population admitted with SARS-CoV-2. Consecutive PLHIV admitted with COVID-19 in 23 hospitals, between 16 April and 23 June 2020, were included. Data of a temporally matched-hospitalized general population were used to compare demography, comorbidities, COVID-19 symptoms, and major outcomes. In total, 36 PLHIV subjects were enrolled; 92% were male and mean age was 44 years. Most patients (83%) were on antiretroviral therapy; mean CD4 count was 557 cells/mm3. Suppressed HIV viremia was found in 68% and 56% had, at least, one comorbidity. Severe COVID-19 occurred in 44.4%, intensive care was required in 22.2%, and five patients died (13.9%). No differences were seen between recovered and deceased patients in CD4 count, HIV viral load, or time since HIV diagnosis. Hypertension and cardiovascular disease were associated with a higher risk of death (p = 0.02 and 0.006, respectively). Compared with general population, the HIV cohort had significantly more men (OR 0.15; IC 95% 0.07-0.31) and younger age (OR 8.68; IC 95% 2.66-28.31). In PLHIV, we found more intensive care unit admission (OR 2.31; IC 95% 1.05-5.07) but no differences in the need for mechanical ventilation or death. In this cohort of PLHIV hospitalized with COVID-19, hypertension and cardiovascular comorbidities, but not current HIV viro-immunologic status, were the most important risk factors for mortality. No differences were found between PLHIV and general population in the need for mechanical ventilation and death.

Vancomicina contra metronidazol en infección por Clostridioides difficile leve-moderada de manejo ambulatorio / Vancomycin or metronidazole in the outpatient treatment of mild-moderate Clostridioides difficile infection

INTRODUCCIÓN: En la diarrea asociada a Clostridioides dfficile (DACD) leve-moderada se recomienda tratar con vancomicina por sobre metronidazol, a pesar de su difícil acceso y poca evidencia en el medio ambulatorio. OBJETIVO: Comparar la tasa de cura clínica y recurrencia entre vancomicina y metronidazol en adultos chilenos con primer episodio leve-moderado de DACD de manejo ambulatorio. MÉTODOS: Cohorte retrospectiva entre enero 2015 y diciembre 2020 en centros de una red de salud universitaria de pacientes de ≥ 18 años con DACD tratados ambulatoriamente. RESULTADOS: Se obtuvieron 161 pacientes, 59% mujeres, edad promedio de 53 años (entre 18 y 94 años). De ellos, 109 (67,7%) usaron metronidazol y 52 (32,3%) vancomicina. En el análisis multivariado ajustado por edad y comorbilidades se obtuvo un OR 3,00 (IC 95% 1,12-9,59) para cura clínica y 0,27 (IC 95% 0,06-0,88) para recurrencia a ocho semanas, ambos a favor de vancomicina, sin diferencias en recurrencia a 12 meses, necesidad de hospitalización o mortalidad. CONCLUSIÓN: La terapia con vancomicina comparada contra metronidazol en el tratamiento ambulatorio de la infección leve-moderada por C. dfficile se asocia a mayor cura clínica y menor tasa de recurrencia a corto plazo, sin diferencias en desenlaces a largo plazo.

BACKGROUND: Recommended treatment against mild cases of Clostridioides difficile associated diarrhea is vancomycin despite the difficulties of access compared to metronidazole. AIM: To compare the effectiveness of vancomycin and metronidazole in Chilean adults with first mild-moderate episode of Clostridiodes difficile infection (CDI). METHODS: Retrospective cohort of patients with CDI between January 2015 and December 2020 treated in centers of a university health network. The patients were adults treated for C. difficile infection on an outpatient basis. Recurrent and severe cases were excluded. Outcomes included clinical cure and recurrence rate. RESULTS: Data from 161 patients was recovered. Fifty-nine percent were women and average age was 53 (18-94). One hundred and nine patients were treated with metronidazole (67.7%) and 52 (32.3%) used vancomycin. Multivariate analysis adjusted by age and comorbidities showed an Odds Ratio of 3.00 (IC 95% 1.12-9.59) for clinical cure and 0.27 (IC 95% 0.06-0.88) for 8-week recurrence rate, both in favor of vancomycin, without differences in 12-month recurrence rate, hospitalization rate nor mortality. CONCLUSIONS: Vancomycin is associated with better short-term outcomes in the treatment of outpatient mild-moderate first episode C. difficile infection, without differences in long term recurrence or mortality when compared with metronidazole.