Protective role of SARS-CoV-2 anti-S IgG against breakthrough infections among European healthcare workers during pre and post-Omicron surge-ORCHESTRA project.

PURPOSE: Anti SARS-CoV-2 vaccination initially showed high effectiveness in preventing COVID-19. However, after the surge of variants of concern, the effectiveness dropped. Several studies investigated if this was related to the decrease of the humoral response over time; however, this issue is still unclear. The aim of this study was to understand whether SARS-CoV-2 anti-S IgG levels can be used to predict breakthrough infection risk and define the timing for further booster doses administration. METHOD: Within the framework of the ORCHESTRA Project, over 20,000 health workers from 11 European centers were enrolled since December 2020. We performed two Cox proportional hazards survival analyses regarding pre-Omicron (from January to July 2021) and Omicron (December 2021-May 2022) periods. The serological response was classified as high (above the 75th percentile), medium (25th-75th), or low (< 25th). RESULTS: Seventy-four (0.33%) and 2122 (20%) health workers were infected during the first and second periods, respectively. Both Cox analyses showed that having high anti-S titer was linked to a significantly lower risk of infection as compared to having medium serological response [HR of high vs medium anti-S titer = 0.27 (95% CI 0.11-0.66) during the first phase, HR = 0.76 (95% CI 0.62-0.93) during the second phase]. CONCLUSION: Vaccine effectiveness wanes significantly after new variants surge, making anti-S titer unsuitable to predict optimal timing for further booster dose administration. Studies on other immunological indicators, such as cellular immunity, are therefore needed to better understand the mechanisms and duration of protection against breakthrough infection risk.

Factors Associated with SARS-CoV-2 Infection Evaluated by Antibody Response in a Sample of Workers from the Emilia-Romagna Region, Northern Italy.

Factors associated with SARS-CoV-2 infection risk are still debated. This case-control study aims to investigate the possible relationship between SARS-CoV-2 infection, evaluated through antibody response, and the main sociodemographic, occupational, clinical-anamnestic, and biochemical factors in a population of Modena province (Northern Italy), mainly workers. Both workers who voluntarily joined the screening campaign proposed by companies and self-referred individuals who underwent serological testing were enrolled. Subjects with antibody positivity were recruited as cases (n = 166) and subjects tested negative (n = 239) as controls. A questionnaire on sociodemographic, occupational, and clinical data was administered through telephone interviews. Serum zinc/iron/copper/chromium/nickel, vitamins D/B12, folates, triglycerides, and LDL/HDL/total cholesterol were measured. Cases lived more often in urban areas (61.8% vs. 57%). Cases and controls did not differ significantly by working macrocategories, but the percentage of workers in the ceramic sector was higher among cases. Low adherence to preventive measures in the workplace was more frequent among seropositives. Folate concentration was significantly lower among cases. Therefore, adequate folate levels, living in rural areas, and good adherence to preventive strategies seem protective against infection. Workers in the ceramic sector seem to be at greater risk; specific factors involved are not defined, but preventive interventions are needed.

Occupational Exposure to Solar Radiation and the Eye: A Call to Implement Health Surveillance of Outdoor Workers.

Globally, hundreds of millions of outdoor workers are exposed to solar radiation (SR) for the majority of their working life. Such occupational exposure is known to induce various adverse health effects to the eyes, mainly related to its ultraviolet (UV) component. The present work is a call-to-action aimed at raising the awareness on the need of health surveillance for the prevention of the chronic ocular diseases in outdoor workers. Photo-chemical chronic damage can induce pterygium at the outer layer of the eye and cataract in the lens. Considering carcinogenic effects, rare squamous-cells tumors of the cornea and/or of the conjunctiva and the ocular melanomas are associated with UV radiation exposure. Solar UV-related eye diseases should be considered as "occupational diseases" when there is sufficient exposure in workers, but they are often not recognized, and/or frequently not reported to the national compensation authorities. Therefore, to prevent the burden of these work-related eye pathologies, an adequate risk assessment with identification of appropriate preventive measures, and a provision of periodic health surveillance to the exposed workers, in particular considering those at higher risk of exposure or with individual susceptibility, should be urgently implemented.

Incidence and Determinants of Symptomatic and Asymptomatic SARS-CoV-2 Breakthrough Infections After Booster Dose in a Large European Multicentric Cohort of Health Workers-ORCHESTRA Project.

BACKGROUND: SARS-CoV-2 breakthrough infections (BI) after vaccine booster dose are a relevant public health issue. METHODS: Multicentric longitudinal cohort study within the ORCHESTRA project, involving 63,516 health workers (HW) from 14 European settings. The study investigated the cumulative incidence of SARS-CoV-2 BI after booster dose and its correlation with age, sex, job title, previous infection, and time since third dose. RESULTS: 13,093 (20.6%) BI were observed. The cumulative incidence of BI was higher in women and in HW aged < 50 years, but nearly halved after 60 years. Nurses experienced the highest BI incidence, and administrative staff experienced the lowest. The BI incidence was higher in immunosuppressed HW (28.6%) vs others (24.9%). When controlling for gender, age, job title and infection before booster, heterologous vaccination reduced BI incidence with respect to the BNT162b2 mRNA vaccine [Odds Ratio (OR) 0.69, 95% CI 0.63-0.76]. Previous infection protected against asymptomatic infection [Relative Risk Ratio (RRR) of recent infection vs no infection 0.53, 95% CI 0.23-1.20] and even more against symptomatic infections [RRR 0.11, 95% CI 0.05-0.25]. Symptomatic infections increased from 70.5% in HW receiving the booster dose since < 64 days to 86.2% when time elapsed was > 130 days. CONCLUSIONS: The risk of BI after booster is significantly reduced by previous infection, heterologous vaccination, and older ages. Immunosuppression is relevant for increased BI incidence. Time elapsed from booster affects BI severity, confirming the public health usefulness of booster. Further research should focus on BI trend after 4th dose and its relationship with time variables across the epidemics.

Digitally measuring solar ultraviolet radiation in outdoor workers: A study protocol for establishing the use of electronic personal dosimeters in Portugal.

Introduction: The rising incidence of skin cancer over the years has made it a significant public and occupational health issue. However, skin cancer is highly preventable, mainly through reduced exposure to solar ultraviolet radiation (UVR), which can be achieved by a variety of individual and collective protective measures and interventions. The relative risk associated with different patterns of exposure to solar UVR differs for the subtypes of keratinocyte cancers (KC). Specifically, whether the exposure is intermittent or continuous, and occurs in an occupational or leisure/recreational setting. The main aim of the study using this protocol is to contribute to raising public and policy awareness on solar UVR-inflicted occupational skin cancers in Lisbon. This will be achieved by performing direct measurements of the solar UVR dose received by outdoor workers using a digital platform. Results will likely contribute to further understanding the risk estimates for keratinocyte cancer estimations in this population. Methods: A prospective observational study will be conducted in Lisbon, Portugal. Personal electronic dosimeters (GENESIS-UV system) integrated with a digital platform will be used to assess occupational solar UVR doses of gardeners, masons, and gravediggers of the municipality of Lisbon. Two hundred and ten outdoor workers will be selected to wear the dosimeter for 1 month each, between April and October during their daily working hours. A digital web-based platform that offers private access to information through dashboard visualization will provide information for the outdoor workers and facilitate communication with the participants. Discussion: The expected results of the overall proposal comprise the occupational solar UVR doses, expressed in standard erythemal dose (SEDs) per day of outdoor work for 7 months. Study data will provide outdoor workers with information on their personal solar UVR exposure during their working hours and an estimate of their risk of developing skin cancer. It is expected that the occupational solar UVR doses of the outdoor workers in Portugal will be above the threshold of 1 to 1.33 SED/day, due to the latitude of Lisbon and the nature of the occupations. The results prospectively should flow into the design of adequate prevention campaigns for skin cancer in outdoor workers.

Risk of cutaneous squamous cell carcinoma due to occupational exposure to solar ultraviolet radiation: Protocol for a systematic review and meta-analysis.

Solar ultraviolet radiation (UVR) is the most significant occupational carcinogenic exposure in terms of the number of workers exposed (i.e., outdoor workers). Consequently, solar UVR-induced skin cancers are among the most common forms of occupational malignancies that are potentially expected globally. This systematic review is registered in PROSPERO (CRD42021295221) and aims to assess the risk of cutaneous squamous cell carcinoma (cSCC) associated to occupational solar UVR exposure. Systematic searches will be performed in three electronic literature databases (PubMed/Medline, EMBASE, and Scopus). Further references will be retrieved by a manual search (e.g., in grey literature databases, internet search engines, and organizational websites). We will include cohort studies and case-control studies. Risk of Bias assessment will be conducted separately for case-control and cohort studies. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) will be used for the certainty of assessment. In case quantitative pooling is not feasible, a narrative synthesis of results will be performed.

Investigation of Possible Factors Influencing the Neutralizing Anti-SARS-CoV-2 Antibody Titer after Six Months from the Second Vaccination Dose in a Sample of Italian Nursing Home Personnel.

The titer of the anti-SARS-CoV-2 antibodies produced after vaccination shows a relevant decay over time, as demonstrated in several studies. However, less is known on the possible factors affecting the entity of this decay. The aim of this study is to analyze a group of individual factors which are possibly associated with anti-SARS-CoV-2 antibody titer decay six months after the second vaccine dose. We report here the results of a follow-up serological analysis and a questionnaire-based evaluation of a sample of workers from an Italian nursing home, vaccinated with two doses of BNT162b2 vaccine in early 2021. The baseline data were collected one month after the vaccine, while in the present analysis we report the data collected six months later. Our data show a relevant decay of the neutralizing antibody titer, even if for all the workers a largely positive response was detected. Moreover, our results demonstrate a possible association between younger age and the absence of previous COVID-19 infection, and a higher decay rate of the anti-SARS-CoV-2 antibodies titer.

Evaluation of an Online Course Promoting Health and Wellbeing for University Students and Employees.

Published studies dealing with health promotion activities, such as the improvement of physical activity and healthy eating, for workers and students prove the effectiveness of these preventive interventions. The consequent benefits include better prevention of cardiovascular risk and an improvement in quality of life. Considering this, an intervention aimed at promoting healthy eating and non-sedentary lifestyles has been implemented within an Italian university: the aim of the present research is to evaluate its effectiveness. The intervention consisted of a targeted asynchronous e-learning two-hour course on healthy eating and non-sedentary lifestyles. The attendants were 2004 university students and employees. We conducted two surveys before and after the training intervention, and, through the responses obtained, we evaluated the effectiveness of the intervention. We applied different statistical methods, including unpaired t-tests and nonparametric tests, principal components and cluster analysis. Our results indicate that the post-training knowledge has been significantly improved, compared to that pre-training (7.3 vs. 8.7, p < 0.001). Moreover, the whole sample showed an improved awareness of the importance of healthy behaviors, and perception of the University as an institution promoting a healthy lifestyle. Through the principal components analysis, we identified a unidimensional latent factor named "health and behaviors". The cluster analysis highlighted that the sub-group reporting the lowest scores at the survey before the training was the one with the highest improvement after the intervention. To the best of our knowledge, this is the first Italian study testing, before and after a health promotion intervention, the knowledge and the attitudes and behaviors towards healthy lifestyles of a group of students and workers. Moreover, we also evaluated the pre- and post-intervention perceived health status, as well as the level of engagement of the attendants, with respect to their colleagues and management in an educational institution promoting wellbeing. The conclusions of our study support the need for further adoption of health promotion training interventions, similar to the one we performed, in order to improve healthy eating and non-sedentary behaviors among workers and students.

SARS-CoV-2 Breakthrough Infections: Incidence and Risk Factors in a Large European Multicentric Cohort of Health Workers.

BACKGROUND: The research aimed to investigate the incidence of SARS-CoV-2 breakthrough infections and their determinants in a large European cohort of more than 60,000 health workers. METHODS: A multicentric retrospective cohort study, involving 12 European centers, was carried out within the ORCHESTRA project, collecting data up to 18 November 2021 on fully vaccinated health workers. The cumulative incidence of SARS-CoV-2 breakthrough infections was investigated with its association with occupational and social-demographic characteristics (age, sex, job title, previous SARS-CoV-2 infection, antibody titer levels, and time from the vaccination course completion). RESULTS: Among 64,172 health workers from 12 European health centers, 797 breakthrough infections were observed (cumulative incidence of 1.2%). The primary analysis using individual data on 8 out of 12 centers showed that age and previous infection significantly modified breakthrough infection rates. In the meta-analysis of aggregated data from all centers, previous SARS-CoV-2 infection and the standardized antibody titer were inversely related to the risk of breakthrough infection (p = 0.008 and p = 0.007, respectively). CONCLUSION: The inverse correlation of antibody titer with the risk of breakthrough infection supports the evidence that vaccination plays a primary role in infection prevention, especially in health workers. Cellular immunity, previous clinical conditions, and vaccination timing should be further investigated.

COVID-19-Related Mortality amongst Physicians in Italy: Trend Pre- and Post-SARS-CoV-2 Vaccination Campaign.

Globally, there has been a high burden of COVID-19-related mortality amongst physicians and other healthcare workers during the ongoing SARS-CoV-2 pandemic. Fortunately, anti-COVID-19 vaccination campaigns have helped to protect frontline workers and reduce COVID-19-related mortality amongst this occupational group. We analyzed COVID-19-related mortality data for doctors in Italy and compared the crude mortality rate between March-May 2020 (i.e., the beginning of the pandemic in Italy, with the highest rates of COVID-19-related deaths) and the same time period in March-May 2021 (high vaccination coverage amongst Italian physicians). The mortality rate was 12 times higher in March-May 2020 compared to the same time period after the start of the Italian vaccination campaign. Moreover, there was a strong inverse correlation between the number of deaths and the cumulative number of vaccine doses administered in the Italian population. Although non-pharmaceutical interventions, virus evolution and environmental factors probably had an effect, our analysis clearly supports the hypothesis that the vaccination campaign helped to protect Italian physicians and reduce COVID-19-related mortality. The latest available death trends from September to October 2021 for both physicians and the general population are also in favor of the need for the third vaccine dose, currently underway for the majority of the population at risk.

Seroprevalence Survey of Anti-SARS-CoV-2 Antibodies in a Population of Emilia-Romagna Region, Northern Italy.

Italy was the first Western European country to be severely hit by the COVID-19 pandemic. Variations in seroprevalence rates were reported according to geographical and temporal differences of previous surveys, as well as depending on demographic and occupational factors. In this cross-sectional study, we evaluated the prevalence of anti-SARS-CoV-2 antibodies in a population of the Emilia-Romagna region in Northern Italy after the first wave in the period from 26 September 2020−26 March 2021. We included 5128 subjects who voluntarily underwent serological tests to determine anti-SARS-CoV-2 antibody positivity, including both self-referred individuals (24.2%) and workers adhering to company screening programs (76.8%). Overall, seroprevalence was 11.3%, higher in self-referred (13.8%) than employed-referred (10.5%) individuals. A slightly higher seroprevalence emerged in women compared to men (12.3% and 10.7%), as well as in the extreme age categories (18.6% for 60−69 years, 18.0% for ≥70 years, and 17.1% for <20 years compared to 7.6% for 20−39 years). Healthcare professionals showed the highest prevalence of seropositivity (22.9%), followed by workers in direct contact with customers, such as the communication, finance, and tourism sectors (15.7%). Overall subgroups seroprevalence increased compared to the first wave data but the trends agreed between the first and subsequent waves, except for an increase in the younger age group and in the sector in direct contact with customers. Among the occupational categories, our study confirms that healthcare workers and workers in the sports sector were at high risk of exposure to SARS-CoV-2.

Seroprevalence of anti-SARS-CoV-2 antibodies in the Northern Italy population before the COVID-19 second wave.

OBJECTIVES: The COVID-19 pandemic is due to SARS-CoV-2 coronavirus infections. It swept across the world in the spring of 2020, and so far it has caused a huge number of hospitalizations and deaths. In the present study, the authors investigated serum anti-SARS-CoV-2 antibody prevalence in the period of June 1-September 25, 2020, in 7561 subjects in Modena, Northern Italy. MATERIAL AND METHODS: The study population included 5454 workers referred to testing by their companies, and 2107 residents in the Modena area who accessed testing through self-referral. RESULTS: The authors found the overall seroprevalence to be 4.7% (95% confidence interval [CI] 4.2-5.2%), which was higher in women (5.4%, 95% CI: 4.5-6.2%) than in men (4.3%, 95% CI: 3.7-4.9%), and in the oldest age groups (7.3%, 95% CI: 5.2-9.3% for persons aged 60-69 years, and 11.8%, 95% CI: 8.6-15.1%, for persons aged ≥70 years). Among the occupational categories, the highest seroprevalence was found in healthcare workers (8.8%, 95% CI: 7.0-10.5%), dealers and vehicle repairers (5.2%, 95% CI: 2.9-7.6%), and workers in the sports sector (4.0%, 95% CI: 1.8-6.1%), while there was little or no such evidence for those employed in sectors such as transport and storage, accommodation and restaurant services, and the school system. CONCLUSIONS: These results have allowed, for the first time, to assess population seroprevalence in this area of Italy severely hit by the epidemic, while at the same time identifying the subgroups at a higher risk of exposure to SARS-CoV-2. Int J Occup Med Environ Health. 2022;35(1):63-74.

Occupational exposure to electromagnetic fields in magnetic resonance environment: an update on regulation, exposure assessment techniques, health risk evaluation, and surveillance.

Magnetic resonance imaging (MRI) is one of the most-used diagnostic imaging methods worldwide. There are ∼50,000 MRI scanners worldwide each of which involves a minimum of five workers from different disciplines who spend their working days around MRI scanners. This review analyzes the state of the art of literature about the several aspects of the occupational exposure to electromagnetic fields (EMF) in MRI: regulations, literature studies on biological effects, and health surveillance are addressed here in detail, along with a summary of the main approaches for exposure assessment. The original research papers published from 2013 to 2021 in international peer-reviewed journals, in the English language, are analyzed, together with documents published by legislative bodies. The key points for each topic are identified and described together with useful tips for precise safeguarding of MRI operators, in terms of exposure assessment, studies on biological effects, and health surveillance.

Protocol for a Systematic Review on the Effectiveness of Interventions to Reduce Exposure to Occupational Solar UltraViolet Radiation (UVR) Among Outdoor Workers.

Background: Solar UltraViolet Radiation (UVR) is considered the most relevant occupational carcinogenic exposure in terms of the number of workers exposed (i.e., outdoor workers) and UVR-induced skin cancers are among the most frequent types of occupational cancers worldwide. This review aims to collect and evaluate all the available preventive interventions conducted on outdoor workers to reduce their solar UVR related risk, with the final purpose of reducing the burden of occupational skin cancers for outdoor workers. Methods: We will search the following databases for peer-reviewed original research published: MEDLINE (through PubMed), Scopus, and EMBASE. We will include only interventional studies, both randomized and non-randomized, with an adequate comparison group, therefore excluding cross-sectional studies, as well as case-reports/series, reviews, and letters/comments. The systematic review will adhere to the "Preferred Reporting Items for Systematic reviews and Meta-Analyses" (PRISMA) guidelines for reporting systematic reviews. After the literature search, studies to be included will be independently reviewed by two Authors, first based on title and abstract, then based on the full text, according to the inclusion criteria. Conflicts will be solved by a third Author. Two authors will independently extract the required data from included studies and perform quality assessment according to the relevant domain for Risk of Bias assessment proposed by the Cochrane collaboration group. In case of sufficient homogeneity of interventions and outcomes evaluated, results from subgroups of studies will be pooled together in a meta-analysis. Discussion: Following the principles for the evaluation of interventions for cancer prevention established by the International Agency for Research on Cancer, this systematic review will investigate the effectiveness of the interventions, and consequently it will provide reliable indications for the actual reduction of skin cancer incidence in outdoor workers.

Factors Associated with SARS-CoV-2 Infection Risk among Healthcare Workers of an Italian University Hospital.

We report the results of a study on the cumulative incidence of SARS-CoV-2 infections in about 6000 workers of the University Hospital of Modena, Northern Italy, in the period March 2020-January 2021, and the relations with some individual and occupational factors. Overall, in healthcare workers (HCW) the cumulative incidence of COVID-19 during the period was 13.8%. Results confirm the role of overweight and obesity as significant risk factors for SARS-CoV-2 infection. Chronic respiratory diseases, including asthma, also proved to be significantly associated with the infection rate. Considering occupational factors, the COVID-19 risk was about threefold (OR: 2.7; 95% CI 1.7-4.5) greater in nurses and nurse aides than in non-HCW, and about double (OR: 1.9; 95% CI 1.2-3.2) in physicians. Interestingly, an association was also observed between infection risk and nightshifts at work (OR: 1.8; 95% CI 1.4-2.3), significantly related to the total number of shifts in the whole eleven-month period. Even if the vaccination campaign has now greatly modified the scenario of SARS-CoV-2 infections among HCW, the results of this study can be useful for further development of health and policy strategies to mitigate the occupational risk related to the new variants of coronavirus, and therefore the evolution of the pandemic.

Subjective Symptoms in Magnetic Resonance Imaging Personnel: A Multi-Center Study in Italy.

Introduction: Magnetic Resonance Imaging (MRI) personnel have significant exposure to static and low-frequency time-varying magnetic fields. In these workers an increased prevalence of different subjective symptoms has been observed. The aim of our study was to investigate the prevalence of non-specific subjective symptoms and of "core symptoms" in a group of MRI personnel working in different centers in Italy, and of possible relationships with personal and occupational characteristics. Methods: The occurrence of 11 subjective symptoms was evaluated using a specific questionnaire with 240 subjects working in 6 different Italian hospitals and research centers, 177 MRI health care and research personnel and 63 unexposed subjects employed in the same departments. Exposure was subjectively investigated according to the type of MRI scanner (≤1.5 vs. ≥3 T) and to the number of MRI procedures attended and/or performed by the personnel, even if no information on how frequently the personnel entered the scanner room was collected. The possible associations among symptoms and estimated EMF exposure, the main characteristics of the population, and job stress perception were analyzed. Results: Eighty-six percent of the personnel reported at least one symptom; drowsiness, headache, and sleep disorders were the most frequent. The total number of symptoms did not differ between exposed persons and controls. Considering the total number of annual MRI procedures reported by the personnel, no significant associations were found nor with the total number of symptoms, nor with "core symptoms." Only subjects complaining of drowsiness also reported a significantly higher mean annual number of MRI procedures with ≤ 1.5 T scanners when compared with exposed subjects without drowsiness. In a multivariate model, subjects with a high level of perceived stress complained of more symptoms (p = 0.0002). Conclusions: Our study did not show any association between the occurrence of reversible subjective symptoms, including the more specific "core symptoms," and the occupational exposure of MRI personnel to static and low-frequency time-varying magnetic fields. On the other hand, the role played by occupational stress appears to be not negligible. In further research in this field, measurements of EMF exposure should be considered.

Risk Perception and Ethnic Background in Construction Workers: Results of a Cross-Sectional Study in a Group of Trainees of a Vocational School in Italy.

Risk perception can be influenced by cultural background. The study aims to evaluate risk perception, considering different ethnicities of construction workers from vocational schools in Italy. We administered a questionnaire investigating four different dimensions: Perceived behavioral control (PBC), Danger perception (DP), Safety climate (SC), and Attitude towards safe actions (ATSA). 562 workers answered: 72.4% from Italy, 14.2% from eastern Europe, 9.4% from Balkans, and 3.9% from North Africa. The participants indicated quite low control, attributable to the haste in performing the job. The workers perceived their specific job tasks as riskier compared to the tasks of their colleagues. They reported as fundamental the respecting of safety rules, but indicating that supervisors do not adequately promote safety behaviors. Finally, construction workers judged as "brave" the colleagues working without protective equipment. When compared to Italians, North Africa workers showed a lower perception of the possibility to control their safe behaviors (p = 0.040), while both eastern Europeans and Balkan obtained higher scores at the ATSA dimension, indicating a kind of fatalistic acceptance of the risky situations at work. Eastern Europeans also showed a lower perception of the dangers (p = 0.002), while Balkan demonstrated a perception of SC even better than the Italian group (p = 0.005).

Frequency of Anti-SARS-CoV-2 Antibodies in Various Occupational Sectors in an Industrialized Area of Northern Italy from May to October 2020.

The results of a voluntary screening campaign for the presence of anti-SARS-CoV-2 serum antibodies are presented, performed on workers in the highly industrialized province of Modena in northern Italy in the period 18 May-5 October 2020. The employment activities of the subjects that tested positive for anti-SARS-CoV-2 IgM and/or IgG antibodies were determined and classified using the International Standard Industrial Classification of All Economic Activities (ISIC). The distribution across different sectors was compared to the proportion of workers employed in the same sectors in the province of Modena as a whole. Workers with anti-SARS-CoV-2 serum antibodies were mainly employed in manufacturing (60%), trade (12%), transportation (9%), scientific and technical activities (5%), and arts, entertainment and recreation activities (4.5%). Within the manufacturing sector, a cluster of workers with positive serological tests was observed in the meat processing sector, confirming recent data showing a possible increased risk of SARS-CoV-2 infection in these workers.

Neutralizing Anti-SARS-CoV-2 Antibody Titer and Reported Adverse Effects, in a Sample of Italian Nursing Home Personnel after Two Doses of the BNT162b2 Vaccine Administered Four Weeks Apart.

BACKGROUND: The immunization of healthcare workers (HCWs) plays a recognized key role in prevention in the COVID-19 pandemic: in Italy, the vaccination campaign began at the end of December 2020. A better knowledge of the on-field immune response in HCWs, of adverse effects and of the main factors involved is fundamental. METHODS: We performed a study on workers at a nursing home in Northern Italy, vaccinated in January-February 2021 with two doses of the BNT162b2 vaccine four weeks apart, instead of the three weeks provided for in the original manufacturer protocol. One month after the second dose, the serological titer of IgG-neutralizing anti-RBD antibodies of the subunit S1 of the spike protein of SARS-CoV-2 was determined. The socio-demographic and clinical characteristics of the subjects and adverse effects of vaccination were collected by questionnaire. RESULTS: In all of the workers, high antibody titer, ranging between 20 and 760 times the minimum protective level were observed. Titers were significantly higher in subjects with a previous COVID-19 diagnosis. Adverse effects after the vaccine were more frequent after the second dose, but no severe adverse effects were observed. CONCLUSIONS: The two doses of the BNT162b2 vaccine, even if administered four weeks apart, induced high titers of anti-SARS-CoV-2 neutralizing IgG in all the operators included in the study.