Factors Associated with SARS-CoV-2 Infection before Vaccination among European Health Care Workers.

BACKGROUND: Health care workers (HCWs) were on the frontline of the current pandemic. We aimed at identifying determinants of SARS-CoV-2 infection and the effectiveness of personal protection equipment (PPE) worn by HCWs before vaccination. METHODS: We abstracted data on SARS-CoV-2 infection based on positive PCR results and sociodemographic characteristics of 38,793 HCWs from public hospitals and public health authorities from 10 European centers. We fitted cohort-specific multivariate logistic regression models to identify determinants of infection and combined the results using random-effects meta-analyses. RESULTS: The overall prevalence of infection before vaccination among HCWs was 9.58%. Infection was associated with the presence of selected symptoms; no association was found between sociodemographic factors and increased risk of infection. The use of PPE and particularly FFP2/FFP3 masks had a different protective effect during the first and second waves of the COVID pandemic. CONCLUSIONS: The study provides evidence that mask use was the most effective PPE in preventing SARS-CoV-2 infection among HCWs.

Effectiveness of prevention of SARS-CoV-2 transmission among unvaccinated Italian healthcare workers.

BACKGROUND: We aimed to investigate the association between personal protective equipment (PPE) use and SARS-CoV-2 infection among healthcare workers (HCWs). METHODS: We analyzed occupational surveillance contact forms followed by a PCR test notified between March and September 2020 by Italian HCWs. The odds ratios (ORs) and 95% Confidence Intervals (CIs) for positive PCR based on HCWs and contacts characteristics were calculated through multivariable logistic regression models. When multiple contacts were potentially effective for a PCR test, they were weighted by the inverse of their number. RESULTS: Overall, 4,883 contacts reported by 2,952 HCWs were analyzed, and 224 contacts among 144 HCWs had positive PCR. No difference was found according to sex, age, employment, or job title, except for an OR of 0.30 (95%CI 0.11-0.78) for resident physicians, compared to administrative staff. The ORs for use of surgical mask were 0.59 (95%CI=0.40-0.86) for use only by HCW, 0.49 (95%CI=0.22-1.07) only by the infected person, and 0.40 (95%CI=0.27-0.60) by both, compared to use by neither. Use of other PPEs was not associated with infection, while the OR for hand sanitation was 0.61 (95%CI=0.40-0.93). HCWs reporting fever, cough, and asthenia had a higher risk of infection. CONCLUSIONS: Use of surgical masks was associated with a 40-60% lower risk of infection, especially when both HCWs and infected individuals used them. Our results quantify the role played by mask use and hand sanitation in preventing SARS-CoV-2 transmission in high-risk circumstances.

The impact of COVID-19 on hospital-based workers influenza vaccination uptake: A two-year retrospective cohort study.

OBJECTIVES: This study aimed at exploring 2020/2021 and 2019/2020 seasonal influenza vaccine uptake among healthcare and non-healthcare workers, hereafter hospital-based workers (HBWs); examining attitudes and motivations for uptake in the 2020/2021 season; and exploring the amount, types, and sources of information used by HBWs. METHODS: A retrospective cohort study. Socio-demographics, working profile, working area, and vaccination status data were collected. Motivations for vaccination uptake in the 2020/2021 season were also explored. Descriptive and inferential statistics were used. RESULTS: Overall, uptake increased from 14.8% in 2019/2020 to 31.7% in 2020/2021. Male workers show greater vaccination uptake than their female counterparts (20.4% vs. 12.6% in 2019/2020, and 36.5% vs. 29.8% in 2020/2021). Uptake increased for healthcare assistants (+8.9%), administrative/managerial staff (+17%), nurses/midwives (+17.1%), non-medical graduate staff (+22.8%), and physicians (+33.2%), while it decreased slightly for resident physicians despite still being one of the most vaccinated categories (-4.6%). Main reasons for vaccination were the desire to protect patients (33.0%) and relatives (51.1%). Lastly, 60.8% of HBWs relied on institutional sources of information; the remainder relied on non-institutional sources including social media and chatting with colleagues. CONCLUSIONS: Vaccination uptake increased in the 2020/21 season. Tailored educational interventions are required on the impact of influenza in care settings, vaccine efficacy, and vaccination safety. Investments in improving HBWs' reliance on institutional sources, and their ability to find them, are also needed.

Vaccination Confidence among Healthcare Workers: Results from Two Anamnestic Questionnaires Adopted in the COVID-19 and Influenza Campaign.

BACKGROUND: Following the announcement of the development of COVID-19 vaccines, hesitancy about the safety of vaccinations and their side effects have spread, despite having the approval of international drug agencies. The aim of this study was to test the hypothesis that concern about side effects may have led people to fill out the COVID-19 anamnestic vaccine questionnaire with greater attention compared to the similar instrument used for the influenza vaccination. METHODS: We analyzed vaccination questionnaires of 218 healthcare workers (HCWs) who underwent both COVID-19 and influenza vaccines in 2020/2021. Outcomes included self-reported allergies, chronic pharmacological treatments, and chronic diseases. We tested the difference in prevalence, analyzed differences using the kappa statistics and concordance correlation, and explored factors associated with differences in reporting. RESULTS: HCWs reported more allergies to substances other than drugs and a higher prevalence of chronic drug intake in the COVID-19 questionnaires than in the influenza ones. Technical staff reported more drug allergies than physicians, and other HCWs reported more outcomes than physicians in the COVID-19 questionnaire. CONCLUSIONS: We found that this population of HCWs reported higher conditions during the 2020 COVID-19 vaccination campaign compared to that of the influenza vaccine. The identification of socio-demographic characteristics of the less vaccine-confident HCWs could help in planning targeted interventions to enhance vaccine adherence.

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.

Serological response after SARS-CoV2 vaccination in healthcare workers: a multicenter study.

INTRODUCTION: Characterizing immunological response following COVID-19 vaccination is an important public health issue. The objectives of the present analysis were to investigate the proportion, level and the determinants of humoral response from 21 days to three months after the first dose in vaccinated healthcare workers (HCWs). METHODS: We abstracted data on level of anti-SARS-CoV-2 Spike antibodies (IgG) and sociodemographic characteristics of 17,257 HCWs from public hospitals and public health authorities from three centers in Northern Italy who underwent COVID-19 vaccination (average 70.6 days after first dose). We fitted center-specific multivariate regression models and combined them using random-effects meta-analyses. RESULTS: A humoral response was elicited in 99.3% of vaccinated HCW. Female sex, young age, and previous COVID-19 infection were predictors of post-vaccination antibody level, and a positive association was also detected with pre-vaccination serology level and with time between pre- and post-vaccination testing, while a decline of antibody level was suggested with time since vaccination. CONCLUSIONS: These results stress the importance of analyzing retrospective data collected via occupational health surveillance of HCWs during the COVID-19 epidemic and following vaccination. They need to be confirmed in larger series based on prospectively collected data.

Choosing between Homologous or Heterologous COVID-19 Vaccination Regimens: A Cross-Sectional Study among the General Population in Italy.

A shortage of COVID-19 vaccines and reports of side-effects led several countries to recommend a heterologous regimen for second vaccine doses. This study aimed to describe the reasons behind individuals' choices of a homologous or a heterologous second vaccination. This cross-sectional study enrolled individuals under 60 who had received a first dose of Vaxzevria and could choose between a homologous or heterologous regimen for their second dose. Quantitative (socio-demographic, clinical characteristics) and qualitative data were collected and analysed through a generalized linear model and thematic analysis, respectively. Of the 1437 individuals included in the analysis, the majority (76.1%) chose a heterologous second dose of the COVID-19 vaccination. More females chose a heterologous vaccination regimen (p = 0.003). Younger individuals also tended to choose heterologous vaccination (p < 0.001). The main motivation in favour of heterologous vaccination was to follow the Italian Ministry of Health recommendations (n = 118; 53.9%). This study showed that most individuals, mainly younger people and females, chose a heterologous dose of COVID-19 vaccination after their first viral vector vaccine. Heterologous vaccinations could be an effective public health measure to control the pandemic as they are a safe and efficient alternative to homologous regimens.

Assessment of air and surfaces contamination in a COVID-19 non-Intensive Care Unit.

BACKGROUND: Severe Acute Respiratory Syndrome - Coronavirus - 2 (SARS-CoV-2)  is a virus, primarily transmitted through  droplets, able to persist on different surfaces and in the air for several hours. During the COVID-19 pandemic, Health Care Workers should be considered a high risk profession. Beside social distancing rules and the proper use of Personal Protective Equipment,  sanitization measures and ventilation system disinfection are essential to reduce viral transmission. OBJECTIVES: This is the first Italian study aiming to assess the magnitude of environmental contamination in a COVID-19 non-Intensive Care Unit. METHODS: In addition to ordinary cleaning procedures, surface and air samplings have been performed before and after the application of two different sanitization devices. Samples have been analyzed with Real Time-Polymerase Chain Reaction in order to find viral RNA. RESULTS: All samples obtained from surfaces and air before and after extra-ordinary sanitization procedures turned out negative for viral detection. DISCUSSION: These findings highlight the efficiency of ordinary cleaning procedures in guaranteeing a safer workplace. The adoption of additional sanitization protocols should be considered in order to further reduce environmental viral contamination.

COVID-19 infection and diffusion among the healthcare workforce in a large university-hospital in northwest Italy.

Backgroud: Since the beginning of the coronavirus disease 2019 (COVID-19) outbreak, healthcare workers (HCWs) have been the workers most likely to contract the disease. Intensive focus is therefore needed on hospital strategies that minimize exposure and diffusion, confer protection and facilitate early detection and isolation of infected personnel. METHODS: To evaluate the early impact of a structured risk-management for exposed COVID-19 HCWs and describe how their characteristics contributed to infection and diffusion. Socio-demographic and clinical data, aspects of the event-exposure (date, place, length and distance of exposure, use of PPE) and details of the contact person were collected. RESULTS: The 2411 HCWs reported 2924 COVID-19 contacts. Among 830 HCWs who were at 'high or medium risk', 80 tested positive (9.6%). Physicians (OR=2.03), and non-medical services -resulted in an increased risk (OR=4.23). Patient care did not increase the risk but sharing the work environment did (OR=2.63). There was a significant time reduction between exposure and warning, exposure and test, and warning and test since protocol implementation. HCWs with management postitions were the main source of infection due to the high number of interactions. DISCUSSION: A proactive system that includes prompt detection of contagious staff and identification of sources of exposure helps to lower the intra-hospital spread of infection. A speedier return to work of staff who would otherwise have had to self-isolate as a precautionary measure improves staff morale and patient care by reducing the stress imposed by excessive workloads arising from staff shortages.