key: cord-0984794-3dfhx8wa authors: Tubiana, Sarah; Burdet, Charles; Houhou, Nadhira; Thy, Michael; Manchon, Pauline; Blanquart, François; Charpentier, Charlotte; Guedj, Jérémie; Alavoine, Loubna; Behillil, Sylvie; Leclercq, Anne; Lucet, Jean-Christophe; Yazdanpanah, Yazdan; Attia, Mikaël; Demeret, Caroline; Rose, Thierry; Bielicki, Julia Anna; Bruijning-Verhagen, Patricia; Goossens, Herman; Descamps, Diane; van der Werf, Sylvie; Lina, Bruno; Duval, Xavier title: High-risk exposure without personal protective equipment and infection with SARS-CoV-2 in in-hospital workers - the CoV-CONTACT cohort date: 2021-02-03 journal: J Infect DOI: 10.1016/j.jinf.2021.01.026 sha: 02328bc27fac766677f72c10d4cd39c509d650d5 doc_id: 984794 cord_uid: 3dfhx8wa nan Two recent studies published in this journal focused on SARS-CoV-2 infection among hospital workers (HWs), the first one reported the prevalence of SARS-CoV-2 carriage among HWs and the second, the clinical presentation of symptomatic HWs in order to identify new cases as early as possible and to stop nosocomial transmission (1, 2) . The objective of the present study was to estimate within the hospital, the risk of in-hospital HWs infection following a high-risk exposure to SARS-CoV-2-infected subject without personal protective equipment. We conducted the CoV-CONTACT study, a prospective cohort which included HWs, hereafter referred to as "contacts" with an high risk exposure to an SARS-CoV-2-infected person (either a patient or a colleague) hereafter referred to as "index", in the 1000 bed Bichat Claude Bernard University Hospital (Paris, France) between March, 3 rd 2020 and April, 27 th 2020 (3) . Exposure was considered to be at high-risk of SARS-CoV-2 transmission if it occurred i) face-to-face, within one meter and without protective surgical or FFP2/N95 mask, and ii) during a discussion or while the index had an episode of coughing or sneezing, and iii) in the 72 hours prior to, or following the virological diagnosis, or during the symptomatic period of the index. Following exposure and upon written informed consent, daily symptoms were self-reported for 30 days; nasopharyngeal swabs for SARS-CoV-2 RT-PCR were performed at inclusion and at days 3, 5, 7 and 12; SARS-CoV-2 IgG serology (LuLISA N and EuroIMMUN (4, 5) ) was assessed at inclusion and at day 30. Confirmed infection was defined by positive RT-PCR or seroconversion, and possible infection by one general and one specific symptom for two consecutive days. SARS-CoV-2 seroconversion was defined as the apparition of a positive SARS-CoV-2 serology at the D30 visit, or as an at least two-fold increase of the LuLISA signal or EuroIMMUN ratio between inclusion and day 30. The primary endpoint was confirmed or possible SARS-CoV-2 infection, hereafter referred to as "SARS-CoV-2 infection". The 146 analysed contacts were exposed to 42 COVID-19 index. No contacts worked in a front-line COVID-19 unit ( ). In the multivariable analysis, the variables associated with SARS-CoV-2 infection were being a non-caregiver HW (aOR=4.1, 95%CI [1.4; 12.2] , p=0.010) and being exposed to a SARS-CoV-2-infected patient (aOR=2.6, 95%CI [1.2; 5.7] , p=0.013) rather to an infected colleague (Table 1) . Following universal masking for HWs on March, 18 th in our hospital, high-risk exposure to SARS-CoV-2-positive patients dropped by 4 and high-risk exposure to SARS-CoV-2-positive colleagues became predominant, making colleagues-to-colleagues transmission a potentially major route of infection (6) . Of note, none of the exposures between a HW and a SARS-CoV-2 infected patient occurred in the front-line services where the mask was worn by all caregivers from the beginning of the epidemic. These exposures occurred, prior to universal masking, in second-line services in which patients had not been previously identified as COVID-19. The profession of the contact subjects was associated with infection, but we did not find any association with the type of activities of the HWs. The 10.9% rate of HWs with SARS-Cov-2 antibodies at inclusion revealing a pre-existing infection while they were not working in front-line services, is close to the seroprevalence of 8.8% reported in the Paris area in the general population during this period (7, 8) . In addition to these HWs already infected at inclusion, 31 others (21.2% of the total population) seroconverted at day 30. We cannot state with certainty that contacts meeting the definition of confirmed infection acquired their infection as a result of the exposure leading to their inclusion in the study. There are several arguments in favor of the link between exposure and infection: the RT-PCR positivity within 12 days after contact, the chronology of symptom onset after contact, and the seroconversion rate observed within the 30 days following the exposure, which is much higher than that observed in the community between March and May 2020 (7, 8) . In addition, the subjects included were counseled to strictly adhere to protective measures to avoid any chain of transmission during the D0-D30 period, limiting the risk of further exposure. All together, the rate of transmission observed in HWs after high-risk exposure, which could be as large as 43%, and close to a recent report (9) , strengthens the conclusion that universal masking of HW, both during contacts with patients and colleagues, and at all times, as soon as the epidemic has been identified, is essential to prevent HWs infection and maintain hospital capacities during outbreaks (10) . Proportions of symptomatic contact subjects among the 146 contacts of the CoV-CONTACT cohort. The orange curve corresponds to contacts subjects with confirmed SARS-CoV-2 infection (i.e., virologically-or immunologically-proven, n=35). The green curve corresponds to contacts subjects with possible SARS-CoV-2 infection (i.e., clinically-suspected without viro-immunological confirmation, n=28). Snapshot PCR surveillance for SARS-CoV-2 in hospital staff in England Clinical presentation of Covid-19 in health care workers from a French University Hospital Clinical and virological data of the first cases of COVID-19 in Europe: a case series High seroprevalence but short-lived immune response to SARS-CoV-2 infection in Paris Performance Characteristics of Four High-Throughput Immunoassays for Detection of IgG Antibodies against SARS-CoV-2 Comparing dynamics and determinants of SARS-CoV-2 transmissions among health care workers of adult and pediatric settings in central Paris Prevalence of SARS-CoV-2 antibodies in France: results from nationwide serological surveillance Pandemic peak SARS-CoV-2 infection and seroconversion rates in London frontline health-care workers Barriers and facilitators to healthcare workers' adherence with infection prevention and control (IPC) guidelines for respiratory infectious diseases: a rapid qualitative evidence synthesis. Cochrane Database Syst Rev Van Der Werf Sylvie CoV-CONTACT Clinical Centers: Abad Fanny, Abry Dominique, Alavoine Loubna Hazevis Béatrice, Hocquet Didier, Hodaj Enkelejda , Ilic-Habensus Emila, Jeudy A, Jeulin Helene Meghadecha Mohamed, Mergeay-Fabre Mayka Waucquier Nawal Coordination and statistical analyses: Burdet Charles, Do Thi Thu Huong Frezouls Wahiba Virological lab: Le Hingrat Quentin Goyard Sophie Biological center