Genetic Load of SARS-CoV-2 in Aerosols Collected in Operating Theaters

After the outbreak of COVID-19, additional protocols have been established to prevent the transmission of the SARS-CoV-2 from the patient to the health personnel and vice versa in health care settings. However, in the case of emergency surgeries, it is not always possible to ensure that the patient is not infected with SARS-CoV-2, assuming a potential source of transmission of the virus to health personnel. This work aimed to evaluate the presence of the SARS-CoV-2 and quantify the viral load in indoor air samples collected inside operating rooms, where emergency and scheduled operations take place. Samples were collected for 3 weeks inside two operating rooms for 24 h at 38 L/min in quartz filters. RNA was extracted from the filters and analyzed using RT-qPCR targeting SARS-CoV-2 genes E, N1 and N2 regions. SARS-CoV-2 RNA was detected in 11.3% of aerosol samples collected in operating rooms, despite with low concentrations (not detected at 13.5 cg/m3 and 10.5 cg/m3 in the scheduled and emergency operating rooms, respectively). Potential sources of airborne SARS-CoV-2 could be aerosolization of the virus during aerosol-generating procedures and in open surgery from patients that might have been recently infected with the virus, despite presenting a negative COVID-19 test. Another source could be related to health care workers unknowingly infected with the virus and exhaling SARS-CoV-2 virions into the air. These results highlight the importance of reinforcing preventive measures against COVID-19 in operating rooms, such as the correct use of protective equipment, screening programs for health care workers, and information campaigns. IMPORTANCE: Operating rooms are critical environments in which asepsis must be ensured. The COVID-19 pandemic entailed the implementation of additional preventative measures in health care settings, including operating theaters. Although one of the measures is to operate only COVID-19 free patients, this measure cannot be always implemented, especially in emergency interventions. Therefore, a surveillance campaign was conducted during 3 weeks in two operating rooms to assess the level of SARS-CoV-2 genetic material detected in operating theaters with the aim to assess the risk of COVID-19 transmission during operating procedures. SARS-CoV-2 genetic material was detected in 11% of aerosol samples collected in operating rooms, despite with low concentrations. Plausible SARS-CoV-2 sources have been discussed, including patients and health care personnel infected with the virus. These results highlight the importance of reinforcing preventive measures against COVID-19 in operating rooms, such as the correct use of protective equipment, screening programs for health care workers and information campaigns.Authors are grateful to funding received from the Fundación BBVA for the project “Detección del SARS-CoV-2 en aerosol atmosférico como herramienta de vigilancia y alerta de la transmisión del COVID-19– AYUDAS FUNDACIÓN BBVA A EQUIPOS DE INVESTIGACIÓN CIENTÍFICA SARS-CoV-2 y COVID-19” (ECO-VET-COVID-BBVA_0029). Authors are also grateful to funding received from Generalitat Valenciana for the project “Detección del SARS-CoV-2 en aerosol atmosférico en ambientes interiores como herramienta de evaluación de medidas sanitarias de prevención y de alerta de la transmisión del COVID-19 (IDIEX COVID-proyecto 4)”. J.M. Delgado-Saborit is a recipient of funds from Generalitat Valenciana - Regional Ministry of Education, Research, Culture and Sport under the Talented Researcher Support Program - Plan GenT (CIDEGENT/2019/064). R. de Llanos was funded by a Beatriz Galindo Fellowship of the Ministerio de Educación y Formación Profesional, Spanish Government (BGP18/00062). S. Porru is a recipient of funds from Margarita Salas postdoctoral contract MGS/2021/19(UP2021-021) financed by the European Union-NextGenerationEU. M. Barneo Muñoz was funded through a “Ajudes Postdoctorals per a la Incorporació a Grups d’Investigació de la UJI” fellowship of the Universitat Jaume I (POSDOC-A/2018/35). We are grateful to R. Navarro Beneito, V. Villalobos Reina and M. Marco López for their help in collecting the samples in the operating theaters. We also want to thank all of the collaborators in the surgical unit of the General University Hospital of Castellón for their participation in this study. COVID-Lap working group: Serrano, J.A.; Badenes, X.; Laguna, M.; Rodrigo, M.; Garau, C.M.; Bosquet Serra, A.; Climent, M.T.; Cañete, S.; Mosteirin, A.; Gomez-Quiles, L.; Villarin, A.; Beltran, H.; Maiocchi, K.; Alos, M.; Jimenez, M.; Garcia, M.; Barrue, P.; Cervera, E.; Vilar, M.J.; Navarro R.; Gutierrez A.; Roger P.; Marco M