The humoral and cellular response to mRNA SARS-CoV-2 vaccine is influenced by HLA polymorphisms.

Host genetic variability contributes to susceptibility to SARS-CoV-2 infection and COVID-19 evolution and the role of HLA system has not clearly emerged, suggesting the involvement of other factors. Studying response to vaccination with Spyke protein mRNA represents an ideal model to highlight whether the humoral or cellular responses are influenced by HLA. Four hundred and sixteen workers, vaccinated with Comirnaty beginning 2021, were selected within the Azienda Ospedaliera Universitaria "Città della Salute e della Scienza di Torino." The humoral response was determined with the LIAISON® kit, while the analysis of the cellular response was performed with the Quantiferon SARS-CoV-2 assay, for the S1 (receptor-binding domain; Ag1) and S1 and S2 (Ag2) subunits of the Spyke protein. Six HLA loci were typed by next-generation sequencing. Associations between HLA and vaccine response were performed with univariate and multivariate analyses. An association was found between A*03:01, B*40:02 and DPB1*06:01 and high antibody concentration and between A*24:02, B*08:01 and C*07:01 and low humoral responses. The haplotype HLA-A*01:01 ~ B1*08:01 ~ C*07:01 ~ DRB1*03:01 ~ DQB1*02:01 conferred an increased risk of low humoral response. Considering cellular responses, 50% of the vaccinated subjects responded against Ag1 and 59% against Ag2. Carriers of DRB1*15:01 displayed a higher cellular response both to Ag1 and Ag2 compared to the rest of the cohort. Similarly, DRB1*13:02 predisposed to a robust cellular response to Ag1 and Ag2, while DRB1*11:04 showed an opposite trend. Cellular and humoral responses to Comirnaty are influenced by HLA. Humoral response is mainly associated to class I alleles, with A*03:01, previously associated to protection against severe COVID-19, and response to vaccination, standing out. Cellular response predominantly involves class II alleles, with DRB1*15:01 and DPB1*13:01 prevailing. Affinity analysis for Spyke peptides is generally in line with the association results.

Cellular Immune Response to BNT162b2 mRNA COVID-19 Vaccine in a Large Cohort of Healthcare Workers in a Tertiary Care University Hospital.

We describe the results of a T-cell immunity evaluation performed after a median elapsed time of 7 months from second-dose BNT162b2 vaccine administration, in a representative sample of 419 subjects from a large cohort of hospital workers. Overall, the Quantiferon SARS-CoV-2 assay detected a responsive pattern in 49.9%, 59.2% and 68.3% of subjects to three different antigenic stimuli from SARS-CoV-2, respectively, with 72.3% of positivity to at least one antigenic stimulus. Potential predictors of cellular response were explored by multivariable analyses; factors associated with positivity to cellular response (to Ag1 antigenic stimulus) were a previous SARS-CoV-2 infection (OR = 4.24, 95% CI 2.34-7.67, p < 0.001), increasing age (per year: OR = 1.03 95% CI 1.01-1.06, p = 0.019 and currently smoking (compared to never smoking) (OR = 1.93, 95% CI 1.11-3.36, p = 0.010). Increasing time interval between vaccine administration and T-cell test was associated with decreasing cellular response (per week of time: OR = 0.94, 95% CI 0.91-0.98, p = 0.003). A blood group A/AB/B (compared to group O) was associated with higher levels of cellular immunity, especially when measured as Ag2 antigenic stimulus. Levels of cellular immunity tended to be lower among subjects that self-reported an autoimmune disorder or an immunodeficiency and among males. Further studies to assess the protective significance of different serological and cellular responses to the vaccine toward the risk of reinfection and the severity of COVID-19 are needed to better understand these findings.

Factors Influencing Level and Persistence of Anti SARS-CoV-2 IgG after BNT162b2 Vaccine: Evidence from a Large Cohort of Healthcare Workers.

We aimed at evaluating quantitative IgG response to BNT162b2 COVID-19 vaccine among health care workers (HCW), and exploring the role of demographic, clinical, and occupational factors as predictors of IgG levels. On May 2021, among 6687 HCW at the largest tertiary care University-Hospital of Northwestern Italy, at a median of 15 weeks (Interquartile range-IQR 13.6-16.0) after second-dose, serological response was present in 99.8%. Seropositivity was >97% in all the subgroups, except those self-reporting immunodeficiency (94.9%). Overall, the median serological IgG value was 990 BAU/mL (IQR 551-1870), with most of subjects with previous SARS-CoV-2 infection or with shorter time lapse (2-8 weeks) between vaccination and serology with values in the highest quintile (>2080). At multivariable analysis, significant predictors of lower values were increasing age, male, current smoking, immunodeficiency, recent occupational contacts, and increasing time lapse from vaccination; conversely, previous infection and recent household contacts were significantly associated with higher IgG levels. Subjects with previous infection kept a very high level (around 2000 BAU/mL) up to 120 days. These results, besides supporting a high serological response up to 4-5 months, suggest predictive factors of faster decay of IgG levels that could be useful in tailoring vaccination strategies.

The impact of COVID-19 on new mesothelioma diagnoses in Italy.

BACKGROUND: The aim of this work was to evaluate the impact of the restrictions put in place to control the COVID-19 pandemic on new diagnoses of malignant mesothelioma (MM) in Italy. METHODS: Twelve of the 21 Italian malignant mesothelioma CORs (regional operating centres) participated. The study included all cases of MM with microscopic confirmation; cases without microscopic confirmation and death certificate only (DCO) were excluded. For each case, information on sex, date of birth, tumor site, morphology, and date of diagnosis was retrieved. We compared the number of incident cases in 2020 with 2019, looking at the overall picture and for four periods: pre-pandemic (January-February), first wave (March-May), low incidence (June-September), and second wave (October-December). RESULTS: A total of 604 cases were registered: 307 in 2019 and 297 in 2020. In the 2020 pre-pandemic period, the incidence was higher than in the same months in 2019 (+45%); there was no significant change during the first wave (+1%) or in the low-incidence period (-3%), while a decrease was observed during the second wave (-32%). However, the data were not homogeneous across the country: the increase in the pre-pandemic period concerned mostly the regions of northern (+61.5%) and central Italy (+43.5%); during the first wave, MM diagnoses increased in the northern (+38.5%) and central (+11.4%) regions but decreased in the southern regions (-52.9%). All these differences are compatible with random fluctuations. CONCLUSION: The COVID-19 pandemic had little or no impact on new MM diagnoses, and variations were not homogeneous throughout the country.

Prevalence, Persistence, and Factors Associated with SARS-CoV-2 IgG Seropositivity in a Large Cohort of Healthcare Workers in a Tertiary Care University Hospital in Northern Italy.

This observational study evaluated SARS-CoV-2 IgG seroprevalence and related clinical, demographic, and occupational factors among workers at the largest tertiary care University-Hospital of Northwestern Italy and the University of Turin after the first pandemic wave of March-April 2020. Overall, about 10,000 individuals were tested; seropositive subjects were retested after 5 months to evaluate antibodies waning. Among 8769 hospital workers, seroprevalence was 7.6%, without significant differences related to job profile; among 1185 University workers, 3.3%. Self-reporting of COVID-19 suspected symptoms was significantly associated with positivity (Odds Ratio (OR) 2.07, 95%CI: 1.76-2.44), although 27% of seropositive subjects reported no previous symptom. At multivariable analysis, contacts at work resulted in an increased risk of 69%, or 24% for working in a COVID ward; contacts in the household evidenced the highest risk, up to more than five-fold (OR 5.31, 95%CI: 4.12-6.85). Compared to never smokers, being active smokers was inversely associated with seroprevalence (OR 0.60, 95%CI: 0.48-0.76). After 5 months, 85% of previously positive subjects still tested positive. The frequency of SARS-COV-2 infection among Health Care Workers was comparable with that observed in surveys performed in Northern Italy and Europe after the first pandemic wave. This study confirms that infection frequently occurred as asymptomatic and underlines the importance of household exposure, seroprevalence (OR 0.60, 95%CI: 0.48-0.76).

Clinical and epidemiological characteristics associated with pneumonia at disease onset in patients admitted for COVID-19 to the Emergency Department of a large Hospital in Piedmont (North-Western Italy).

OBJECTIVES: to explore clinical and epidemiological characteristics associated with an imaging feature of COVID-19 pneumonia at disease onset, in order to identify factors that may be evaluable by general practitioners at patient's home, and which may lead to identify a more severe disease, needing hospitalization. DESIGN: this is a retrospective/prospective observational hospital cohort. SETTING AND PARTICIPANTS: the study population includes all patients consecutively admitted to the emergency department of Città della salute e della scienza University Hospital from 01.03 to 31.05.2020 with a confirmed diagnosis of SARS-CoV-2 infection. MAIN OUTCOME MEASURES: patients were classified in two groups according to the findings of X-ray imaging, lung ultrasound and chest computer tomography, as pneumonia or not pneumonia patients. RESULTS: in multivariable analysis, factors most strongly associated with emergency department admission with pneumonia were age, oxygen saturation <90% (adj OR 4.16 ;95%CI 1.44-12.07), respiratory rate >24 breaths/min (adj OR 6.50; 95%CI 2.36-17.87), fever ≥38° (adj OR 3.05; 95%CI 1.53-6.08) and the presence of gastroenteric symptoms (vomiting and diarrhea). A delay (> 7 days) between the appearance of the initial lung symptoms (cough and dyspnea) and the admission to the emergency department was also related to a higher probability of receiving a positive imaging report (OR 4.99; 95%CI 2,02-12,34). CONCLUSIONS: in order to reorganize the management of COVID-19 patients in Italy, in view of the risk of a second wave of epidemic or of local outbreaks, it would be desirable to relocate the triage, and possibly the patient's care, from hospital to home. In this scenario it is important to identify all symptoms and signs associated with COVID-19 pneumonia that would facilitate the decision-making process of GPs leading to patients hospitalization.

[Covid-19 and clinical-epidemiological research in Italy: proposal of a research agenda on priority topics by the Italian association of epidemiology]. / Covid-19 e ricerca clinico-epidemiologica in Italia: proposta di un'agenda di ricerca su temi prioritari da parte dell'Associazione italiana di epidemiologia.

BACKGROUND: the Covid-19 pandemic has provoked a huge of clinical and epidemiological research initiatives, especially in the most involved countries. However, this very large effort was characterized by several methodological weaknesses, both in the field of discovering effective treatments (with too many small and uncontrolled trials) and in the field of identifying preventable risks and prognostic factors (with too few large, representative and well-designed cohorts or case-control studies). OBJECTIVES: in response to the fragmented and uncoordinated research production on Covid-19, the   italian Association of Epidemiology (AIE) stimulated the formation of a working group (WG) with the aims of identifying the most important gaps in knowledge and to propose a structured research agenda of clinical and epidemiological studies considered at high priority on Covid-19, including recommendations on the preferable methodology. METHODS: the WG was composed by 25 subjects, mainly epidemiologists, statisticians, and other experts in specific fields, who have voluntarily agreed to the proposal. The agreement on a list of main research questions and on the structure of the specific documents to be produced were defined through few meetings and cycles of document exchanges. RESULTS: twelve main research questions on Covid-19 were identified, covering aetiology, prognosis, interventions, follow-up and impact on general and specific populations (children, pregnant women). For each of them, a two-page form was developed, structured in: background, main topics, methods (with recommendations on preferred study design and warnings for bias prevention) and an essential bibliography. CONCLUSIONS: this research agenda represents an initial contribution to direct clinical and epidemiological research efforts on high priority topics with a focus on methodological aspects. Further development and refinements of this agenda by Public Health Authorities are encouraged.