key: cord-0881381-apalv0wi authors: Paris, C.; Tadie, E.; Heslan, C.; Gary-Bobo, P.; Oumary, S.; Sitruck, A.; Wild, P.; Tattevin, P.; Thibault, V.; Garlantezec, R. title: Role of non-aerosols activities in the transmission of SARS-Cov-2 infection among health care workers. date: 2021-04-26 journal: nan DOI: 10.1101/2021.04.22.21255922 sha: 70ec3d90abf0e360227fd14af0f040238ba9dac5 doc_id: 881381 cord_uid: apalv0wi Abstract Background. Since the emergence of SARS-CoV-2, health care workers (HCWs) have been on the front line in caring for COVID-19 patients. Better knowledge of risk factors for SARS-CoV-2 infection is crucial for the prevention of disease among this population. Methods. We conducted a seroprevalence survey among HCWs in a French university hospital after the first wave (May-June 2020), based on a validated lateral flow immuno-assay test (LFIAT) for SARS-CoV-2. Demographic characteristics as well as data on the working characteristics of COVID-19 and non-COVID-19 wards and 23 care activities were systematically recorded. The effectiveness of protective equipment was also estimated, based on self-declaration of mask use. SARS-CoV-2 IgG status was modelled by multiple imputations approach, accounting for the performance of the test and data on serum validation ELISA immunoassay. Findings. Among the 3,234 enrolled HCWs, the prevalence of SARS-CoV-2 IgG was 3.8%. Contact with relatives or HCWs who developed COVID-19 were risk factors for SARS-CoV-2 infection, but not contact with COVID-19 patients. In multivariate analyses, suboptimal use of protective equipment during naso-pharyngeal sampling, patient mobilisation, clinical and eye examination was associated with SARS-CoV-2 infection. In addition, patients washing and dressing and aerosol-generating procedures were risk factors for SARS-CoV-2 infection with or without self-declared appropriate use of protective equipment. Interpretation. Main routes of transmission of SARS-CoV-2 IgG among HCWs were i) contact with relatives or HCWs with COVID-19, ii) close or prolonged contact with patients, iii) aerosol-generating procedures. of HCWs among patients with coronavirus disease . Initial reports from China found that 52 HCWs represented 3.8% of all cases (1, 716 HCWs/44,674) but this proportion was 29% of HCWs in 53 patients admitted for severe pneumonia 1 . In the USA, HCWs represented 16% of the 315,531 cases of 54 COVID-19 among individuals with a known occupational status 2 . According to the European CDC, the 55 proportion of HCWs among COVID-19 cases varied from 9% to 26% in several EU countries with 56 available data 3 . Finally, a recent meta-analysis reported an overall seroprevalence of SARS-CoV-2 57 antibodies among HCWs of 8.7% 95CI 6.7-10.9% 4 . In France, 67,811 HCWs were infected by SARS-CoV-58 2 between March 2020 and February, 2021 5 . In this context, understanding the main routes of 59 transmission of SARS-CoV-2 in HCWs is an important public health question. Several care activities are 60 known or suspected to be associated with increased risk of transmission of several coronaviruses 61 (SARS, MERS and SARS-CoV-2), in particular aerosol-generating activities such as intubation, high-flow 62 oxygen and mechanical ventilation 6, 7 . In France, a recent study including 2,329 infected HCWs reported 63 that masks were not worn during eye examinations in 47.6% of cases, or during high-risk activities in 64 19 .4% of cases 8 . Other circumstances of possible contamination among these HCWs were the initial 65 absence of recommendations to wear masks in care settings or the use of protective equipment only 66 with suspected or confirmed COVID-19 patients 9, 10 . Current knowledge on the pathways of SARS-CoV-67 2 transmission among HCWs remains limited, and requires further analysis. We aimed to precisely 68 assess main care activities associated with the risk of SARS-CoV-2 infection in HCWs by performing a 69 large sero-prevalence study associated with questionnaires on contacts, and practices in a French 70 university hospital, after the first wave. 71 The clinical COVID-19 status was defined as probable if patients presented with fever, 107 dyspnoea, and at least one of the following: cough, myalgia, headache or unusual fatigue, or if patients 108 presented with anosmia or ageusia. Patients with other symptoms were defined as possible Our validation study 12 Among the 3,234 participants that completed the supplemental questionnaire and underwent 140 LFIAT (Figure 1 ), 120 (3.8%) HCWs presented with IgG SARS-CoV-2 according to the 'by combination' 141 definition (Table I) . We observed close-to-significant differences (p = 0.06) among occupations, with 142 cleaners, stretcher-bearers and residents having the highest rate of positive tests. There were no 143 significant differences according to sex, age, smoking status, or presence of comorbidities. The number 144 of symptoms highly correlated with the presence of SARS-CoV-2 IgG, as well as the clinical definition 145 of COVID-19 status (Table II) . Overall, in univariate analyses (Table III) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021 This large sero-epidemiological study, which included more than 3,000 HCWs in a French 171 university hospital after the first epidemic wave, highlights several possible factors in the risk of 172 transmission of SARS-CoV-2. First, our results confirm that, during the first epidemic wave, contact 173 with both relatives or HCWs with COVID-19 were the two main risk factors for SARS-CoV-2 infection, 174 while working in COVID-19 wards or contact with COVID-19 patients was not associated with an 175 increased risk. Second, we confirmed that certain tasks performed by HCWs that increase the risk of 176 aerosolization also increase the risk of SARS-CoV-2 transmission, particularly when use of protective 177 equipment was sub-optimal, such as interventions on the upper respiratory tract or nasopharyngeal 178 sampling. Our results also suggest that certain tasks associated with daily care, such as patients 179 washing, dressing, mobilisation, and eye or clinical examinations also increased the risk of SARS- contact, and contact with bodily secretions increased the risk of coronavirus infections, but they found 207 less convincing arguments for other types of exposure such as non-invasive positive-pressure 208 ventilation, nebulizers use, manipulation of oxygen masks, and high-flow oxygen. This review 209 confirmed the protective effect of using a mask, either surgical or N95 1 , previously reported 20 . For 210 coronaviruses, N95 masks are not generally found to be more protective than surgical masks for most 211 at-risk exposures, albeit some authors reported better protection with N95 masks 21, 22 We also found a higher risk of SARS-CoV-2 IgG positivity associated with two auxiliary-nurses activities, 218 namely patients washing and dressing, and their mobilisation. The masks used while performing these 219 activities are surgical, and our results suggest that this level of protection may not be appropriate. One 220 explanation may be that these activities require close, and prolonged contact with patients, two risk 221 factors that may increase the risk of SARS-CoV-1 transmission 21, 23, 24 . For SARS-CoV-2, to the best of 222 our knowledge, only two studies suggested that duration of care may be a risk factor for infection. Greater London, to that of HCWs in their cohort study, and suggested that these data more likely 244 reflect general community transmission than in-hospital exposure. Finally, Steensels et al. 18 Our study has several limitations. First, data on the use of protective equipment, particularly 249 masks, were only declarative, and some HCWs may have over-or under-reported their use. We tried 250 to limit this effect by attributing the quality of protection independently of the tasks using the same 251 algorithm throughout the database. However, we observed associations for only a few activities, and 252 the observation of a coherent gradient of transmission risk with the quality of protection support the 253 validity of our findings. Another limitation was the low sero-prevalence, resulting in a low statistical 254 power. Nonetheless, we were able to highlight several activities associated with the risk of SARS-CoV-255 2 infection, even in multivariable analyses. We also only considered SARS-CoV-2 IgG as the LFIAT shows 256 low performances for the detection of SARS-CoV-2 IgM 11 . As we began our study at the end of May, 257 two months after the peak of the first epidemic wave in France, the effect on our prevalence estimate 258 was probably minimal. Finally, we only analysed the protective effect of masks, without considering 259 gloves, visors, and lab coats. Thus, our results primarily focus mostly on the risk of of SARS-CoV-2 260 transmission by inhalation. 261 Our study also has several strengths. The determination of SARS-CoV-2 status was based on a 262 LFIA test that we previously validated 12 . Our knowledge of the quality of both the negative and positive 263 predictive values allowed us to include these data in our models, using multiple imputation after 264 stratification on the LFIA test response. This method, generally used to complete missing data, was a 265 good tool to correct our sero-prevalence results according to the validation measurement. Moreover, 266 several authors have recommended accounting for such errors 29, 30 . Thus, despite certain differences 267 between the 'in combination' and 'multiple imputation' definitions, these approaches provide more 268 confidence in our results. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021. ; https://doi.org/10.1101/2021.04.22.21255922 doi: medRxiv preprint ensure that our sample was representative. A comparison of demographic and occupational 274 characteristics between respondents and non-respondents did not find any difference (data not 275 shown). 276 As previously mentioned, our study allowed us to precisely study the role of several care-277 associated activities, including nursing and auxiliary-nursing care. Our methodology, using factor 278 analyses coupled to multivariate logistic regression also allowed us to take into account statistical 279 correlations among the variables. However, residual correlations may explain some of the variation in 280 the observed associations between specific care activities and the presence of SARS-COV-2 antibodies. 281 As already mentioned and to the best of our knowledge, no previous study on this subject have used 282 these statistical approaches. 283 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021 At a time during which second, and sometime third, wave of the SARS-CoV-2 pandemic is 285 sweeping across the world, and during which many HCWs must care for COVID-19 patients, our study 286 highlights several possible pathways of transmission associated with specific medical, nursing or 287 auxiliary-nursing activities. Although effective protective equipment was already being used by HCWs, 288 these findings support the possible role of less known situations in the transmission of SARS-CoV-2. In 289 particular, long-duration, non-aerosol generating activities close to patients such as mobilising patients 290 in their beds, washing and dressing them, and clinical or eye examinations may be at higher risk than 291 previously thought. Better use of adequate protective equipment during these activities must be 292 encouraged to better protect HCWs. Further studies are required to better understand the pathways 293 of SARS-CoV-2 transmission among HCWs. 294 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021 DM : data missing 296 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 26, 2021 Yes, suboptimal protective equipment 79 (92.9) 6 (7.1) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 26, 2021 CP and RG conceived the study. CP, RG, VT and PT contributed to the protocol and design of the study. ET, PGB, SO contributed to the implementation of the study or data collection. CH and VT conducted the ELISA serological assays. CP, AS, RG and PW conducted the statistical analysis. CP and RG contributed to the preparation of the report. All authors critically reviewed and approved the final version. All authors had full access to all the data in the study and had final responsibility for the decision to submit for publication. Association between 2019-nCoV transmission and N95 respirator use Team CC-R Characteristics of Health Care Personnel with COVID-19 -United States Coronavirus disease 2019 (COVID-19) in the EU/EEA and the UK. Rapid Risk Assessment, eighth update edn Kaitelidou D Seroprevalence of SARS-CoV-2 antibodies and associated factors in healthcare workers: a systematic review and meta-analysis SPF. 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We thank Pr Boudjema, Pr Malledant, Nicolas Mevel, Sophie Huitorel, Agnes Gazzola, Anne-Sophie Jouault, and Valerie Turmel for their help in the organisation of this study. This study was funded by a grant from the Nominoe Fund and the Rennes CHU. The authors declare no conflicts of interest.