Association between the overall burden of comorbidity and Ct values among the older patients with Omicron infection: Mediated by inflammation.

Objectives: To investigate the associations between the overall burden of comorbidity, inflammatory indicators in plasma and Ct values among the elderly with COVID-19. Methods: We conducted a retrospective observational study. The results of each nucleic acid test of during hospitalization were obtained. Linear regression models assessed the associations between the overall burden of comorbidity, inflammatory indicators in plasma and Ct values among the elderly. A causal mediation analysis was performed to assess the mediation effects of inflammatory indicators on the association between the overall burden of comorbidity and Ct values. Results: A total of 767 COVID-19 patients aged ≥ 60 years were included between April 2022 and May 2022. Patients with a high burden of comorbidity had significantly lower Ct values of the ORF gene than subjects with a low burden of comorbidity (median, 24.81 VS 26.58, P < 0.05). Linear regression models showed that a high burden of comorbidity was significantly associated with higher inflammatory responses, including white blood cell count, neutrophil count and C-reactive protein. Also, white blood cell count, neutrophil count, C-reactive protein and the overall burden of comorbidity assessed by age-adjusted Charlson comorbidity index were independent risk factors for the Ct values. A mediation analysis detected the mediation effect of white blood cells on the association between the burden of comorbidity and Ct values, with the indirect effect estimates of 0.381 (95% CI: 0.166, 0.632, P < 0.001). Similarly, the indirect effect of C-reactive protein was -0.307 (95% CI: -0.645, -0.064, P = 0.034). White blood cells and C-reactive protein significantly mediated the relationship between the burden of comorbidity and Ct values by 29.56% and 18.13% of the total effect size, respectively. Conclusions: Inflammation mediated the association between the overall burden of comorbidity and Ct values among elderly with COVID-19, which suggests that combined immunomodulatory therapies could reduce the Ct values for such patients with a high burden of comorbidity.

Effectiveness of Inactivated Vaccine against SARS-CoV-2 Delta Variant Infection in Xiamen, China-A Test-Negative Case-Control Study.

OBJECTIVE: Vaccine effectiveness can measure herd immunity, but the effectiveness of inactivated vaccines in Xiamen remains unclear. Our study was designed to understand the herd immunity of the COVID-19 inactivated vaccine against the SARA-CoV-2 Delta variant in the real world of Xiamen. METHODS: We carried out a test-negative case-control study to explore the vaccine's effectiveness. Participants aged over 12 years were recruited. A logistic regression was used to estimate the odds ratio (OR) of the vaccine among cases and controls. RESULTS: This outbreak began with factory transmission clusters, and spread to families and communities during the incubation period. Sixty percent of cases were confirmed in a quarantine site. A huge mass of confirmed cases (94.49%) was identified within three days, and nearly half of them had a low Ct value. Following an adjustment for age and sex, a single dose of inactivated SARS-CoV-2 vaccine yielded the vaccine effectiveness (VE) of the overall case, of 57.01% (95% CI: -91.44~86.39%), the fully VE was 65.72% (95% CI: -48.69~88.63%) against COVID-19, 59.45% against moderate COVID-19 and 38.48% against severe COVID-19, respectively. The VE of fully vaccinated individuals was significantly higher in females than in males (73.99% vs. 46.26%). The VE among participants aged 19~40 and 41~61 years was 78.75% and 66.33%, respectively, which exceeds the WHO's minimal threshold. Nevertheless, the VE in people under 18 and over 60 years was not observed because of the small sample size. CONCLUSIONS: The single-dose vaccine had limited effectiveness in preventing infection of the Delta variant. The two doses of inactivated vaccine could effectively prevent infection, and clinical mild, moderate, and severe illness caused by the SARS-CoV-2 Delta variant in people aged 18-60 years in the real world.

Clinical characteristics of the first known cases of death caused by COVID-19 pneumonia.

Severe pneumonia caused by COVID-19 has resulted in many deaths worldwide. Here, we analyzed the clinical characteristics of the first 17 reported cases of death due to COVID-19 pneumonia in Wuhan, China. Demographics, initial symptoms, complications, chest computerized tomography (CT) images, treatments, and prognoses were collected and analyzed from the National Health Committee of China data. The first 17 reported deaths from COVID-19 were predominately in older men; 82.35% of patients were older than 65 years, and 76.47% were males. The most common initial symptoms were fever or fatigue (14 cases, 82.35%), respiratory symptoms, such as cough (12 cases, 70.59%), and neurological symptoms, such as headache (3 cases, 17.65%). The most common finding of chest CT was viral pneumonia (5 cases, 29.41%). Anti-infectives (11 cases, 64.71%) and mechanical ventilation (9 cases, 52.94%) were commonly used for treatment. Most of the patients (16 cases, 94.12%) died of acute respiratory distress syndrome (ARDS). Our findings show that advanced age and male gender are effective predictors of COVID-19 mortality, and suggest that early interventions to reduce the incidence of ARDS may improve prognosis of COVID-19 pneumonia patients.