key: cord-1026172-u1d3e8dz
authors: Maltezou, Helena C.; Tseroni, Maria; Daflos, Charalampos; Anastassopoulou, Cleo; Vasilogiannakopoulos, Antonios; Daligarou, Olga; Panagiotou, Maria; Botsa, Evanthia; Spanakis, Nikolaos; Lourida, Athanasia; Tsakris, Athanasios
title: Environmental testing for SARS-CoV-2 in three tertiary-care hospitals during the peak of the third COVID-19 wave
date: 2021-08-26
journal: Am J Infect Control
DOI: 10.1016/j.ajic.2021.08.022
sha: 33e5e920aef702b81199a8e5e383bb60f26aed0f
doc_id: 1026172
cord_uid: u1d3e8dz

Contamination of surfaces has been implicated in transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We tested by real-time PCR for SARS-CoV-2 contamination environmental samples from three hospitals during the peak of the third pandemic wave. Overall, 19 of 463 (4.1%) samples tested positive: 12 of 173 (6.9%) samples from a COVID-19 hospital, 3 of 177 (1.7%) samples from a non-COVID-19 hospital, and 4 of 113 (3.5%) samples from a pediatric hospital with dedicated COVID-19 clinics. Most positive samples originated from emergency departments (EDs) (47.3%) and the intensive care units (ICUs) (26.3%) of the COVID-19 hospital. Positive samples belonged almost exclusively (18/19) to the highly transmissible B.1.1.7 cluster, that might explain environmental contamination at this stage of the pandemic. The frequency and efficiency of disinfection in high-risk patient areas, such as EDs and ICUs, should be reinforced, especially during this period where highly transmissible variants of concern are widespread.

Contamination of surfaces has been implicated in transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We tested by real-time PCR for SARS-CoV-2 contamination environmental samples from three hospitals during the peak of the third pandemic wave. Overall, 19 of 463 (4.1%) samples tested positive:

12 of 173 (6.9%) samples from a COVID-19 hospital, 3 patient areas, such as EDs and ICUs, should be reinforced, especially during this period where highly transmissible variants of concern are widespread.

 We tested by PCR for SARS-CoV-2 environmental samples from three hospitals.  Overall, 19 of 463 (4.1%) samples tested positive for SARS-CoV-2.  Most positive samples (12 of 173; 6.9%) originated from the COVID-19 hospital.  Most positive samples originated from emergency departments (47.3%) and

ICUs (26.3%).  The frequency and efficiency of disinfection in high-risk areas should be reinforced.

Contamination of surfaces has been implicated in transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We tested by real-time PCR for SARS-CoV-2 contamination environmental samples from three hospitals during the We assessed the SARS-CoV-2 environmental contamination in three hospitals at the peak of the third pandemic wave in Greece.

The study was conducted in a 411-bed COVID-19 referral hospital The study was approved by the hospitals' Ethics Committees.

In Table 1) . In our study, the highest positivity rates were detected in PPE, EDs, and the ICU of Hospital A. At that time Hospital A hospitalized only COVID-19 patients. SARS-CoV-2 was detected in several medical devices and equipment in various areas in the EDs. In a heavily contaminated Chinese hospital, 37.5% of ICU samples were positive. 5 In a Singapore hospital, 20-25% of medical equipment tested positive. 2 Similar to our findings, 5.2% of samples from the ED of a hospital tested positive for SARS-CoV-2. 6 In this study, 10.9% of surfaces in direct contact and medical devices tested positive. 6 The higher positivity rate of EDs samples is partially explained by the overcrowded situation, the prolonged close proximity of patients, and gaps in infection control. 7 Our findings indicate that disinfection should be performed more often in the EDs and the ICU. Disinfection procedures should also improve, cleaners should be trained accordingly and audits applied.

In our study no sample from COVID-19 rooms, non-patients areas, laboratories and lobbies tested positive, indicating sufficient disinfection. However, in two Israeli hospitals SARS-CoV-2 was detected in 52.7% of samples around symptomatic COVID-19 patients. 8 Another study found that the COVID-19 rooms were heavily contaminated (30% positivity). 2 Furthermore, SARS-CoV-2 has been detected in 40-50% of beepers, water machine buttons, elevator buttons, computer mice and telephones in a Chinese hospital, indicating heavy contamination. 5 Similarly, common equipment often tested positive in a London hospital with a 52.3% contamination rate. 4 In accordance with others, we found high Ct values in all environmental samples. [2] [3] [4] 9 The detection of viral RNA does not necessarily translate to a replication-competent virus. A cutoff value of 34 cycles using an assay targeting the RdRp gene has been suggested for SARS-CoV-2 infectivity. 10 In conclusion, we found that <5% of environmental samples from three hospitals collected during the peak of the third pandemic wave were positive. Most positive samples were collected from the EDs and the ICU of the COVID-19 referral hospital.

The frequency and efficiency of disinfection in high-risk patient areas should increase and cleaners should be trained accordingly.

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Detection of SARS-CoV-2 within the healthcare environment: a multi-centre study conducted during the first wave of the COVID-19 outbreak in England

Investigating SARS-CoV-2 surface and air contamination in an acute healthcare setting during the peak of the COVID-19 pandemic in London

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Preanalytical issues and cycle threshold values in SARS-CoV-2 real-time RT-PCR testing: should test results include these?

We are thankful to the Infection Control Committees of the participating hospitals.We also thank Anastasia Tedoma for technical assistance. The opinions presented in this article are those of the authors, and do not necessarily represent those of their institutions.