Thrombotic events following Covid-19 vaccines compared to Influenza vaccines.

IMPORTANCE: The actual risk of thrombotic events after Covid-19 vaccination is unknown. OBJECTIVE: To evaluate the risk of thrombotic events after Covid-19 vaccination. DESIGN: Retrospective cohort study which included consecutive adult patients vaccinated with the first dose of Covid-19 vaccine between January 1 and May 30, 2021, and a historic control group, defined as consecutive patients vaccinated with influenza vaccine between March 1 and July 30, 2019. SETTING: Hospital Italiano de Buenos Aires, a tertiary hospital in Argentina. PARTICIPANTS: Non-Hospitalized Adults vaccinated with the first dose of a Covid-19 vaccine. EXPOSURE: Vaccination with Covid-19 vaccines available during the study period: Gam-COVID-Vac (Sputnik), ChAdOx1 nCoV-19 (AstraZeneca/Oxford or Covishield), BBIBP-CorV (Beijing Institute of Biological Products) (Sinopharm). Active comparator group exposure was Influenza vaccine. MAIN OUTCOME: Primary endpoint was cumulative incidence of any symptomatic thrombotic event at 30 days, defined as the occurrence of at least one of the following: symptomatic acute deep venous thrombosis (DVT); symptomatic acute pulmonary embolism (PE); acute ischemic stroke (AIS); acute coronary syndrome (ACS) or arterial thrombosis. RESULTS: From a total of 29,985 adult patients who received at least a first dose of Covid-19 vaccine during study period and 24,777 who received Influenza vaccine in 2019, we excluded those who were vaccinated during hospitalization. We finally included 29,918 and 24,753 patients respectively. Median age was 73 years old (IQR 75-81) and 67% were females in both groups. Thirty six subjects in the Covid-19 vaccination group (36/29,918) and 15 patients in the Influenza vaccination group (15/24,753) presented at least one thrombotic event. The cumulative incidence of any thrombotic event at 30 days was 12 per 10,000 (95%CI 9-17) for Covid-19 group and 6 per 10,000 (95%CI 4-10) for Influenza group (p-value=0.022). CONCLUSIONS AND RELEVANCE: This study shows a significant increase in thrombotic events in subjects vaccinated with Covid-19 vaccines in comparison to a control group. The clinical implication of these findings should be interpreted with caution, in light of the high effectiveness of vaccination and the inherent risk of thrombosis from Covid-19 infection itself.

Low Incidence of Symptomatic Thrombotic Events in Adult Patients Hospitalized with Coronavirus 19: A Retrospective Cohort Study.

BACKGROUND: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic, there have been many reports of increased incidence of venous thromboembolism and arterial events as a complication. OBJECTIVE: To determine the incidence of symptomatic thrombotic events (TEs) in patients hospitalized for SARS-CoV2 disease (coronavirus 19 [Covid-19]). METHODS: A retrospective single-center cohort study with adult patients with a positive reverse transcriptase-polymerase chain reaction (rt-PCR) for SARS-CoV2, included from the date of diagnosis of Covid-19 and followed for 90 days or until death. RESULTS: A total of 1621 patients were included in this study. The median age was 73 years (interquartile range25th-75th [IQR] 53-87 years) and 57% (913) were female. Overall mortality was 21.6% (348). The overall incidence of symptomatic TEs within 90 days of diagnosis was 1.8% (30 of 1621) occurring in 28 patients, including an incidence of pulmonary embolism of 0.9% (15, 95% confidence interval [CI] 0.60%-1.6%), deep venous thrombosis of 0.61% (10, 95% CI 0.2%-1%), ischemic stroke of 0.25% (4, 95% CI 0.09%-0.65%), and ischemic arterial events of 0.06% (1, 95% CI 0.008%-0.43%). No acute coronary syndrome events were recorded. The incidence of symptomatic TEs was significantly lower in the general ward than in intensive care units (1.2% vs 5.7%; p < .001). The median time since positive rt-PCR for SARS-CoV2 to symptomatic TE was 22.5 days (IQR 19-43 days). There was no significant difference in the proportion of patients receiving (53.6%) and not receiving thromboprophylaxis (66.5%) and the development of TEs. CONCLUSION: The overall incidence of symptomatic TEs among these patients was lower than the incidence previously reported.

Risk of readmission to the emergency department in mild COVID-19 outpatients with telehealth follow-up.

Introduction: To describe patients´ characteristics of confirmed COVID-19 with mild symptoms discharged home from the Emergency Department (ED) and followed using telemedicine, to estimate ED-readmission rates and hospitalization, and to explore associated factors with these clinical outcomes. Methods: We performed a retrospective cohort study in Hospital Italiano de Buenos Aires from June to August 2020, which included patients with mild COVID-19 symptoms, diagnosed with a positive result. Follow-up occurred from discharged until ED-readmission or 14 days. We estimate cumulative incidence using the Kaplan-Meier model and associated factors using logistic regression. Results: We included 1,239 patients, with a median of 41 years and 53.82% male. A total of 167 patients were readmitted to the ED within 14 days, with a global incidence rate of 13.08% (95%CI 11.32-15.08). Of these, 83 required hospitalization (median time from diagnosis 4.98 days), 5.98% was not related to any COVID-19 complication, and five patients died. After adjustment by confounders (age ≥65, sex, diabetes, hypertension, former smoking, active smoking, fever, diarrhea, and oxygen saturation), we found significant associations: former smoking (adjusted OR 2.09, 95% CI 1.31-3.34, p0 .002), fever (aOR 1.56, 95% CI 1.07-2.28, p0.002) and oxygen saturation (aOR 0.82, 95% CI 0.71-0.95, p0.009). Conclusion: The 13% rate of ED-readmission during 14 days of follow-up of mild symptomatic COVID-19 patients initially managed as outpatients with telehealth is highly significant in hospital management, quality performance, and patient safety.

Introducción: Describir las características de los pacientes COVID-19 con síntomas leves dados de alta desde la Central de Emergencias de Adultos (CEA) y seguidos en forma ambulatoria mediante telemedicina. Estimar las tasas de re-consulta a CEA y hospitalización, y explorar los factores asociados a estos desenlaces. Métodos: Cohorte retrospectiva de Junio a Agosto 2020 en el Hospital Italiano de Buenos Aires, que incluyó personas COVID-19 con síntomas leves. Se siguieron durante 14 días hasta la ocurrencia de re-consulta en CEA y/o hospitalización. Se utilizaron modelos de Kaplan-Meier y regresión logística. Resultados: De un total de 1.239 pacientes, con una mediana de 41 años y 53,82% varones, 167 pacientes re-consultaron a CEA, con una tasa de incidencia global a los 14 días del 13,08% (IC del 95% 11,32 a 15,08). De estos, 83 requirieron hospitalización (media de 4,98 días), el 6% no se relaciona con COVID-19 y 5 pacientes fallecieron. Después del ajuste por factores confundidores (edad ≥65, sexo, diabetes, hipertensión, ex tabaquismo, tabaquismo activo, fiebre, diarrea y saturación de oxígeno), encontramos asociaciones significativas: tabaquismo anterior (ORa 2,09, IC95% 1,31-3,34, p0=0,002), fiebre (ORa 1,56, IC95% 1,07-2,28, p=0,002) y saturación de oxígeno (ORa 0,82, IC95% 0,71-0,95, p=0,009). Conclusión: La tasa del 13% de re-consulta a CEA durante 14 días de seguimiento resultó muy significativa para la gestión hospitalaria, la calidad del desempeño y la seguridad del paciente.

A Randomized Trial of Convalescent Plasma in Covid-19 Severe Pneumonia.

BACKGROUND: Convalescent plasma is frequently administered to patients with Covid-19 and has been reported, largely on the basis of observational data, to improve clinical outcomes. Minimal data are available from adequately powered randomized, controlled trials. METHODS: We randomly assigned hospitalized adult patients with severe Covid-19 pneumonia in a 2:1 ratio to receive convalescent plasma or placebo. The primary outcome was the patient's clinical status 30 days after the intervention, as measured on a six-point ordinal scale ranging from total recovery to death. RESULTS: A total of 228 patients were assigned to receive convalescent plasma and 105 to receive placebo. The median time from the onset of symptoms to enrollment in the trial was 8 days (interquartile range, 5 to 10), and hypoxemia was the most frequent severity criterion for enrollment. The infused convalescent plasma had a median titer of 1:3200 of total SARS-CoV-2 antibodies (interquartile range, 1:800 to 1:3200). No patients were lost to follow-up. At day 30 day, no significant difference was noted between the convalescent plasma group and the placebo group in the distribution of clinical outcomes according to the ordinal scale (odds ratio, 0.83; 95% confidence interval [CI], 0.52 to 1.35; P = 0.46). Overall mortality was 10.96% in the convalescent plasma group and 11.43% in the placebo group, for a risk difference of -0.46 percentage points (95% CI, -7.8 to 6.8). Total SARS-CoV-2 antibody titers tended to be higher in the convalescent plasma group at day 2 after the intervention. Adverse events and serious adverse events were similar in the two groups. CONCLUSIONS: No significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma and those who received placebo. (PlasmAr ClinicalTrials.gov number, NCT04383535.).