Intensity and Dynamics of Anti-SARS-CoV-2 Immune Responses after BNT162b2 mRNA Vaccination: Implications for Public Health Vaccination Strategies.

The aim of our study was to investigate the immunogenicity of the BNT162b2 vaccination according to the age and medical status of vaccinated individuals. A total of 511 individuals were enrolled (median age: 54.0 years, range: 19-105); 509 of these individuals (99.6%) received two doses of BNT162b2 at an interval of 21 days. IgG and IgA responses were evaluated on days 21, 42, 90, and 180 after the first dose with chemiluminescent microparticle and ELISA assays. The cell-mediated immune responses were assessed by an automated interferon-gamma release assay. We demonstrated positive antibody responses after vaccination for the majority of enrolled participants, although waning of IgG and IgA titers was also observed over time. We further observed that the intensity of humoral responses was positively correlated with increased age and prior COVID-19 infection (either before or after the first vaccination). Moreover, we found that only a medical history of autoimmune disease could affect the intensity of IgA and IgG responses (3 weeks after the primary and secondary immunization, respectively), while development of systemic adverse reactions after the second vaccination dose was significantly associated with the height of IgG responses. Finally, we identified a clear correlation between humoral and cellular responses, suggesting that the study of cellular responses is not required as a routine laboratory test after vaccination. Our results provide useful information about the immunogenicity of COVID-19 vaccination with significant implications for public health vaccination strategies.

Repeated Leftover Serosurvey of SARS-CoV-2 IgG Antibodies in Greece, May to August 2020.

A serosurvey of IgG antibodies against SARS-CoV-2 was conducted in Greece between May and August 2020. It was designed as a cross-sectional survey and was repeated at monthly intervals. The leftover sampling methodology was used and a geographically stratified sampling plan was applied. Of 20,110 serum samples collected, 89 (0.44%) were found to be positive for anti-SARS-CoV-2 antibodies, with higher seroprevalence (0.35%) observed in May 2020. The highest seroprevalence was primarily observed in the "30-49" year age group. Females presented higher seroprevalence compared to males in May 2020 (females: 0.58% VS males: 0.10%). This difference reversed during the study period and males presented a higher proportion in August 2020 (females: 0.12% VS males: 0.58%). Differences in the rate of seropositivity between urban areas and the rest of the country were also observed during the study period. The four-month infection fatality rate (IFR) was estimated to be 0.47%, while the respective case fatality rate (CFR) was at 1.89%. Our findings confirm low seroprevalence of COVID-19 in Greece during the study period. The young adults are presented as the most affected age group. The loss of the cumulative effect of seropositivity in a proportion of previous SARS-CoV-2 infections was indicated.

Repeated leftover serosurvey of SARS-CoV-2 IgG antibodies, Greece, March and April 2020.

A serosurvey of IgG antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) was performed during March and April 2020. Among 6,586 leftover sera, 24 (0.36%) were positive, with higher prevalence in females, older individuals and residents of large urban areas. Seroprevalence was estimated at 0.02% and 0.25%, respectively, in March and April, infection fatality rate at 2.66% and 0.54%. Our findings confirm low COVID-19 incidence in Greece and possibly the effectiveness of early measures.

Serum amyloid alpha in parapneumonic effusions.

STUDY OBJECTIVES: To assess serum amyloid alpha (SAA) pleural fluid levels in parapneumonic effusion (PPE) and to investigate SAA diagnostic performance in PPE diagnosis and outcome. METHODS: We studied prospectively 57 consecutive patients with PPE (empyema (EMP), complicated (CPE), and uncomplicated parapneumonic effusion (UPE)). SAA, CRP, TNF-α, IL-1ß, and IL-6 levels were evaluated in serum and pleural fluid at baseline. Patients were followed for 6-months to detect pleural thickening/loculations. RESULTS: Pleural SAA levels (mg/dL) median(IQR) were significantly higher in CPE compared to UPE (P < 0.04); CRP levels were higher in EMP and CPE compared to UPE (P < 0.01). There was no significant difference between IL-1ß, IL-6, TNF-α level in different PPE forms. No significant association between SAA levels and 6-month outcome was found. At 6-months, patients with no evidence of loculations/thickening had significantly higher pleural fluid pH, glucose levels (P = 0.03), lower LDH (P = 0.005), IL-1ß levels (P = 0.001) compared to patients who presented pleural loculations/thickening. CONCLUSIONS: SAA is increased in complicated PPE, and it might be useful as a biomarker for UPE and CPE diagnosis. SAA levels did not demonstrate considerable diagnostic performance in identifying patients who develop pleural thickening/loculations after a PPE.

Systemic and airway inflammation and the presence of emphysema in patients with COPD.

The aim of this study was to determine the impact of HRCT-confirmed emphysema on biomarkers evaluating airway and systemic inflammation in COPD patients. Forty-nine consecutive male COPD outpatients with stable COPD were divided in two groups according to the presence or absence of emphysema on HRCT. Patients underwent pulmonary function tests, plus assessment of exercise capacity, body composition and quality of life. Biomarkers were measured in serum (CRP, interleukin-6, TNF-alpha, leptin, adiponectin, osteocalcin, insulin growth factor-1, and systemic oxidative stress), in plasma (fibrinogen and VEGF) and in whole blood (B-type natriuretic peptide). TNF-alpha, 8-isoprostane and pH were additionally measured in exhaled breath condensate. Patients with emphysema had more severe lung function impairment, lower body-mass index and fat-free mass index, and poorer quality of life. Additionally, they presented increased systemic oxidative stress and plasma fibrinogen and lower BNP compared to patients without emphysema. After proper adjustment for disease severity, all differences remained with the exceptions of body-mass index, fat-free mass index and BNP. COPD patients with HRCT-confirmed emphysema present increased systemic oxidative stress and fibrinogen, suggesting that they may be more prone to the systemic consequences of COPD compared to patients without emphysema.

Clinical, functional and biochemical changes during recovery from COPD exacerbations.

The pathways underlying chronic obstructive pulmonary disease exacerbations (ECOPD) remain unclear. This study describes the clinical, functional and biochemical changes during recovery from ECOPD. Thirty hospitalized patients with Anthonisen's type-I ECOPD were evaluated on days 0 (admission), 3, 10 and 40. A five-symptom score (TSS), performance status and quality of life were evaluated. Post-bronchodilator spirometry, blood gases, oxidative stress, C-reactive protein (CRP), serum amyloid-A (SAA), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and fibrinogen were also measured. Patients were classified as early- or late-recoverers, based on whether dyspnea had returned to pre-exacerbation level by day 10. Most clinical, functional and biochemical parameters improved during follow-up. CRP and IL-6 levels reduced on Day 3 (p<0.05), whereas SAA on Day 10 (p<0.01). TNF-alpha was reduced on Days 3 and 10, but on Day 40 its levels returned to baseline. Fibrinogen and WBC reduced only by day 40. TSS and dyspnea were correlated inversely with FEV(1) on days 3, 10 and 40. Although late-recoverers had lower FEV(1) on admission, none of the reported measurements on admission and day 3 predicted early recovery. During recovery from ECOPD, symptomatic improvement correlates only with post-bronchodilator FEV(1) whereas systemic inflammatory burden subsidence does not correlate with clinical and functional changes. Although late-recoverers have lower FEV(1) on admission, none of the measured parameters is able to predict early symptomatic recovery.