Breath-, air- and surface-borne SARS-CoV-2 in hospitals

Abstract

The COVID-19 pandemic has brought an unprecedented crisis to the global health sector. When discharging COVID-19 patients in accordance with throat or nasal swab protocols using RT-PCR, the potential risk of reintroducing the infection source to humans and the environment must be resolved. Here, 14 patients including 10 COVID-19 subjects were recruited; exhaled breath condensate (EBC), air samples and surface swabs were collected and analyzed for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR) in four hospitals with applied natural ventilation and disinfection practices in Wuhan. Here we discovered that 22.2% of COVID-19 patients (n = 9), who were ready for hospital discharge based on current guidelines, had SARS-CoV-2 in their exhaled breath (~10 5 RNA copies/m 3 ). Although fewer surface swabs (3.1%, n = 318) tested positive, medical equipment such as face shield frequently contacted/used by healthcare workers and the work shift floor were contaminated by SARS-CoV-2 (3–8 viruses/cm 2 ). Three of the air samples (n = 44) including those collected using a robot-assisted sampler were detected positive by a digital PCR with a concentration level of 9–219 viruses/m 3 . RT-PCR diagnosis using throat swab specimens had a failure rate of more than 22% in safely discharging COVID-19 patients who were otherwise still exhaling the SARS-CoV-2 by a rate of estimated ~1400 RNA copies per minute into the air. Direct surface contact might not represent a major transmission route, and lower positive rate of air sample (6.8%) was likely due to natural ventilation (1.6–3.3 m/s) and regular disinfection practices. While there is a critical need for strengthening hospital discharge standards in preventing re-emergence of COVID-19 spread, use of breath sample as a supplement specimen could further guard the hospital discharge to ensure the safety of the public and minimize the pandemic re-emergence risk.

A literature survey of the robotic technologies during the COVID-19 pandemic

“…Meanwhile, it is also suggested to integrate robot with the gas release system to sterilise the area and prevent disease spreading [ 43 ]. In an application in China, a robot was also utilised to collect air samples in the hospital [ 44 ]. Robotics is needed in an advanced HealthTech ecosystem, together with photonics, biomaterials, smart systems, digital health and textile [ 45 ].…”

LAMP Diagnostics at the Point-of-Care: Emerging Trends and Perspectives for the Developer Community

“…This led researchers to explore alternative specimen types such as breath, odor, and saliva. There has been an increased interest in screening for COVID-19 via collection of exhaled breath for direct virus detection [120]; however, this method requires further clinical evaluation to determine the reliability and accuracy. Saliva is a promising sample for COVID-19 testing because it is easy and painless to collect and seemingly has a high viral load [121].…”

Detecting SARS-CoV-2 in the Breath of COVID-19 Patients

“…During 2020, the human race suffered from the COVID-19 pandemic (1-6) but fortunately learned the importance of controlling transmission through air (7)(8)(9)(10)(11). As a main source of aerosol spread of respiratory viruses, exhaled breath of patients has been confirmed as a potential risk using various methods of sampling and subsequent testing (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Several groups have reported SARS-CoV-2 positivity in samples of exhaled breath condensate (EBC) (21)(22)(23)(24)(25), and based on Ct values, Ma et al further showed that EBC-positive COVID-19 patients exhaled millions of SARS-CoV-2 RNA copies per hour (23).…”

“…As a main source of aerosol spread of respiratory viruses, exhaled breath of patients has been confirmed as a potential risk using various methods of sampling and subsequent testing (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Several groups have reported SARS-CoV-2 positivity in samples of exhaled breath condensate (EBC) (21)(22)(23)(24)(25), and based on Ct values, Ma et al further showed that EBC-positive COVID-19 patients exhaled millions of SARS-CoV-2 RNA copies per hour (23). Standard diagnosis of viruses based on swabs or serum has been rapidly developed (17,(26)(27)(28)(29), while auxiliary methods, such as trace biomarkers of COVID-19 in exhalations, have also been explored (18)(19)(20).…”