COVID-19 outbreaks in hospital workers during the first COVID-19 wave

Piapan, Linda; Michieli, Paola De; Ronchese, F; Rui, Francesca; M, Peresson; Segat, Ludovica; D’Agaro, Pierlanfranco; Negro, Corrado; Bovenzi, Massimo; Filon, Francesca Larese

doi:10.1093/occmed/kqab161

Cited by 18 publications

(18 citation statements)

References 22 publications

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“…HCWs of ASUGI Trieste (N = 5019), including two major teaching hospitals, primary care services, health districts, public health services, and administrative/management services have been systematically screened for COVID-19 since the start of the pandemic, becoming an ideal population to estimate the infection risk, the associated factors, and the effectiveness of the respective vaccines [9][10][11][12][13][14][15].…”

Section: Methodsmentioning

confidence: 99%

SARS-CoV-2 Infection in Health Care Workers of Trieste (North-Eastern Italy), 1 October 2020–7 February 2022: Occupational Risk and the Impact of the Omicron Variant

Cegolon

Ronchese

Ricci

et al. 2022

Viruses

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Vaccination coverage against COVID-19 among health care workers (HCWs) of the University Health Agency Giuliano-Isontina (ASUGI) of Trieste (North-eastern Italy) by 1 January 2022 was 90.4% with at least one vaccine dose, 84.9% with at least 2 doses, and 75.1% with 3 doses, 98.2% with Comirnaty (Pfizer BioNtech, New York, NY, USA) versus 1.8% with Spikevax (Moderna, Cambridge, MA, USA). From 1 October 2020 to 7 February 2022, 1652 SARS-CoV-2 infections were notified in HCWs of ASUGI Trieste. Although the overall risk of SARS-CoV-2 contagion increased over time, the rate of occupational infections progressively declined, from 42.5% during the second COVID-19 wave to 15.6% in the fifth. Between 1 January–7 February 2022 (a period dominated by the Omicron variant), albeit no COVID-19-associated hospitalizations were recorded in HCWs of ASUGI Trieste, 669 SARS-CoV-2 infections were counted against 367 cases observed from 1 October to 31 December 2020, the 3 months preceding the implementation of the vaccination campaign against COVID-19. Job tasks and health care settings turned out to be the most significant risk factors for SARS-CoV-2 infection. However, the effect of workplace prevailed over job task on the biological risk, with greater rates of SARS-CoV-2 infections observed among HCWs operating in areas with higher levels of circulation of the virus, particularly COVID-19 dedicated units.

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Section: Methodsmentioning

confidence: 99%

SARS-CoV-2 Infection in Health Care Workers of Trieste (North-Eastern Italy), 1 October 2020–7 February 2022: Occupational Risk and the Impact of the Omicron Variant

Cegolon

Ronchese

Ricci

et al. 2022

Viruses

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“…Infectious respiratory aerosols can be liberated in large quantities when talking, singing, or simply breathing [14][15][16] and may build up to high concentrations in room air, if the space is not adequately ventilated [10]. Consequently, poorly ventilated spaces that may contain infectious individuals, such as hospital wards, can pose a considerable threat to patients and healthcare workers (HCWs) alike, with numerous nosocomial COVID-19 outbreaks reported in the literature [17][18][19][20][21][22][23][24][25]. The problem can be particularly acute in wards containing older and/or immunocompromised patients who are vulnerable to developing severe disease following viral infection.…”

Section: Introductionmentioning

confidence: 99%

Impact of supplementary air filtration on airborne particulate matter in a UK hospital ward

D¹,

Butler

Peters

et al. 2022

Preprint

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Background During the COVID-19 pandemic, aerosol spread of SARS-CoV-2 has been a major problem in healthcare facilities, resulting in increased use of supplementary HEPA filtration to mitigate transmission. We report here a natural experiment that occurred when an air filtration unit (AFU) on an inpatient ward for older people was accidentally switched off. Aim To assess aerosol transport within the ward and determine whether the AFU reduced particulate matter (PM) levels in the air. Methods Time-series PM, CO2, temperature and humidity data (at 1 minute intervals) was collected from multiple sensors around the ward over two days in August 2021. During this period, the AFU was accidentally switched off for approximately 7 hours, allowing the impact of the intervention on particulates (PM1-PM10) to be assessed using a Mann-Whitney test. Pearson correlation analysis of the PM and CO2 signals was also undertaken to evaluate the movement of airborne particulates around the ward. Findings The AFU greatly reduced PM counts of all sizes throughout the ward space (p<0.001 for all sensors), with PM signals positively correlated with indoor CO2 levels (r = 0.343-0.817; all p<0.001). Aerosol particle counts tended to rise and fall simultaneously throughout the ward space when the AFU was off, with PM signals from multiple locations highly correlated (e.g. r = 0.343-0.868 (all p<0.001) for PM1). Conclusion Aerosols freely migrated between the various sub-compartments of the ward, suggesting that social distancing measures alone cannot prevent nosocomial transmission of SARS-CoV-2. The AFU greatly reduced PM levels throughout the ward space.

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“…Since the start of the pandemic, epidemiological investigations on COVID-19 have focused on healthcare workers (HCWs) due to their elevated biological risk, high COVID-19 vaccination coverage and routine yet mandatory screening for SARS-CoV-2 infection [ 1 , 2 , 3 , 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

COVID-19 Incidence and Vaccine Effectiveness in University Staff, 1 March 2020–2 April 2022

et al. 2023

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Background: University workers undergo intense social interactions due to the frequent contact with students and colleagues and lectures in crowdy conditions. The aim of our study was to assess the incidence of COVID-19 infection and vaccine effectiveness in a cohort of workers of the University of Trieste from 1 March 2020 (start of the pandemic) through 2 April 2022. Methods: The University of Trieste implemented a number of public health policies to contain the spread of SARS-CoV-2 on the campus, including prompt contact tracing, the enhanced ventilation of all premises, fomites disinfection and the mandatory use of face masks indoors. In compliance with the surveillance protocol of the local public health department, university personnel were tested for SARS-CoV-2 by polymerase chain reaction (PCR) on a nasopharyngeal swab on demand, in the event of symptoms consistent with COVID-19 or for contact tracing, following close contact with a confirmed COVID-19 case. The incidence rates of SARS-CoV-2 infections were estimated as the number of cases by the number of person-days (p-d) at risk. The multivariable Cox proportional hazard regression model was employed to investigate the risk of primary COVID-19 infection, adjusting for a number of potential confounders and expressing the risk as the adjusted hazard ratio (aHR) with a 95% confidence interval (95% CI). Results: The incidence of SARS-CoV-2 infection among the university staff was lower than that of healthcare workers (HCWs) of the same area. Compared to unvaccinated colleagues (6.55 × 10,000 p-d), the raw incidence of SARS-CoV-2 infection was higher among university workers immunized with one (7.22 × 10,000 p-d) or two (7.48 × 10,000 p-d) doses of the COVID-19 vaccine, decreasing in those receiving the booster (1.98 × 1000 p-d). The risk of infection increased only in postgraduate medical trainees (aHR = 2.16; 95% CI: 1.04; 4.48), though this was limited to the Omicron transmission period. After the implementation of the national vaccination campaign against COVID-19, workers immunized with the booster were less likely than unvaccinated workers to be infected by SARS-CoV-2 both before (aHR = 0.10; 95% CI: 0.06; 0.16) and after (aHR = 0.37; 95% CI: 0.27; 0.52) the Omicron transmission period. The vaccine effectiveness of the booster was 90% (=(1−0.10) × 100) before versus 63% (=(1−0.37) × 100) during the Omicron wave, without a significant difference between homologous (three doses of m-RNA vaccines) and heterologous (first two doses of Vaxzevria followed by a third dose of m-RNA vaccine) immunization. Conclusions: The incidence of SARS-CoV-2 infection in the university staff was lower than that of HCWs of ASUGI, likely because the testing-on-demand schedule inevitably missed asymptomatic infections. Therefore, the observed significantly protective effect of the booster dose in university personnel referred to symptomatic SARS-CoV-2 infections. The infection prevention and control policies implemented by the University of Trieste managed to equalize the biological risk between the administrative and teaching staff.

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COVID-19 outbreaks in hospital workers during the first COVID-19 wave

Cited by 18 publications

References 22 publications

SARS-CoV-2 Infection in Health Care Workers of Trieste (North-Eastern Italy), 1 October 2020–7 February 2022: Occupational Risk and the Impact of the Omicron Variant

SARS-CoV-2 Infection in Health Care Workers of Trieste (North-Eastern Italy), 1 October 2020–7 February 2022: Occupational Risk and the Impact of the Omicron Variant

Impact of supplementary air filtration on airborne particulate matter in a UK hospital ward

COVID-19 Incidence and Vaccine Effectiveness in University Staff, 1 March 2020–2 April 2022

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