key: cord-0898122-nnamjntr authors: Wu, Songjie; Wang, Ying; Jin, Xuelan; Tian, Jia; Liu, Jianzhong; Mao, Yiping title: Environmental contamination by SARS-CoV-2 in a designated hospital for coronavirus disease 2019 date: 2020-05-12 journal: Am J Infect Control DOI: 10.1016/j.ajic.2020.05.003 sha: 590d329f0125ae0ebab3794866183b93abe597b1 doc_id: 898122 cord_uid: nnamjntr BACKGROUND: COVID-19 is characterized by risk of nosocomial transmission; however, the extent of environmental contamination and its potential contribution of environmental contamination to SARS-CoV-2 transmission are poorly understood. This study aimed to investigate whether environmental contamination may play a role in SARS-CoV-2 transmission. METHODS: Air samples were collected by natural precipitation, and environmental surface samples were collected by conventional surface swabbing. SARS-CoV-2 RNA detection was performed using reverse transcription polymerase chain reaction. RESULTS: Viral RNA was not detected in the 44 air samples. The positive rates in 200 environmental surface samples in medical areas (24.83%) was higher than that in living quarters (3.64%), with a significant difference (P<0.05). The positive rates were 25.00% and 37.50% for the general isolation ward and ICU, respectively, and no significant difference was observed between them (P=0.238). The top five sampling sites with a positive rate in medical areas were beepers (50.00%), water machine buttons (50.00%), elevator buttons (42.86%), computer mouses (40.00%), and telephones (40.00%). CONCLUSIONS: Most of the touchable surfaces in the designated hospital for COVID-19 were heavily contaminated, suggesting that the environment is a potential medium of disease transmission. These results emphasize the need for strict environmental surface hygiene practices and enhanced hand hygiene to prevent the spread of the virus. contagious, and people are generally susceptible. Many healthcare workers have been infected during patient care [3] . SARS-CoV-2 is mainly transmitted through infected respiratory droplets and close contact with the infected person. Further, there is risk for aerosol transmission when the virus is exposed to high concentrations of aerosol for a long time in a relatively closed environment [4, 5] . An environment contaminated with the feces and urine of infected patients may also cause transmission through aerosol or contact [6] . To contain the spread of SARS-CoV-2, some designated hospitals have been appointed by the Chinese government as special treatment sites for the patients with COVID-19. Patients in the designated hospital were in high density, the SARS-CoV-2 could be excreted by respiratory droplets or aerosols, contaminating the surrounding environment. It has been reported that SARS-CoV-2 can remain viable and infectious in aerosols for hours and on surfaces up to days [7] . If environmental disinfection is not thorough or effective, SARS-CoV-2 may spread widely and can even lead to nosocomial infection. Researchers suggest that improving the environmental sanitation quality can reduce the spread of pathogens in hospitals and even prevent hospital infection outbreak [8] . However, the extent of environmental contamination by SARS-CoV-2 and the potential contribution of this contamination to SARS-CoV-2 transmission are poorly understood. The present study was performed in a designated hospital to evaluate environmental contamination in the air and surfaces by SARS-CoV-2 RNA qualitative detection and to investigate whether environmental contamination may play a role in SARS-CoV-2 transmission. This study was conducted in Wuhan No. 7 Hospital, which was originally a comprehensive Grade 2A hospital and then became one of the first batch designated hospitals for COVID-19 in Hubei Province. The hospital started to treat patients with COVID-19 on January 22, 2020. It comprises general isolation wards, intensive care unit (ICU), fever clinic, clinical laboratory, office areas, and restrooms( Figure) . All regions of the hospital were divided into two categories: (1) moderate-and high-risk regions, including the medical areas such as patient room, nurses' station, buffer room for taking off personal protective equipment(PPE), and fever clinic, and 2) low-risk regions, including the living quarters such as the restrooms, office areas, and buffer room for taking on PPE. Numbered labels correspond to environmental sampling sites. ① beepers; ② bed rails; ③ desktops;④ bedside tables;⑤ oxygen cylinder valve;⑥ medical equipment such as ventilator, monitors, and X-ray devices, etc;⑦ door handles;⑧ elevator buttons；⑨ keyboards；⑩ computer mouses；⑪ telephones; ⑫ water machine buttons; ○ Arefers to air samples; The medical area with moderate and high risk contains patient's room, nurses station, buffer room for taking off PPE , and elevator; the living quarters with low risk contains the rest rooms, office area, and buffer room for taking on PPE. Flocked swabs, premoistened with viral transport medium, were collected from environmental surfaces that were frequently touched by patients or healthcare workers. The surfaces included beeper, keyboard, computer mouse, telephone, door handle, desktop, medical equipment, bedrail, bedside table, oxygen cylinder valve, elevator button, and others such as refrigerator, IV port, and sample transfer box. Air samples from medical areas were collected through natural precipitation according to the Hygienic Standard for Disinfection in Hospitals [9] . All samples were collected under emergency conditions around 8:00 am before routine cleaning and disinfection and were delivered to the clinical laboratory immediately after collection. The suspension was used for real-time reverse transcription polymerase chain reaction (RT-PCR) assay of SARS-CoV-2 RNA. The real-time RT-PCR assay was performed using a SARS-CoV-2 nucleic acid detection kit according to the manufacturer's protocol (Shanghai ZJ Bio-Tech Co., Ltd.). Two different targets on the SARS-CoV-2 genome, namely, the RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) genes, were employed, and a third target, the envelope (E) gene, was used for real-time quantitative PCR [10] . A sample was considered positive when the qPCR Ct value was ≤43. Statistical analyses were performed using SPSS version 20.0 software (SPSS Inc.). The differences in the positive rates between the medical areas and the living quarters and the general isolation ward and ICU were compared by the χ2 test; the Fisher exact test was used when data were limited. A two-sided α of less than 0.05 was considered to indicate statistical significance. Of the 44 air samples collected in medical areas, none of all was positive for SARS-CoV-2 as assessed by RT-PCR (Table 1) . The positive rates of samples from environmental surfaces in different areas are shown in Table 2 Aerosol transmission of the virus could lead to the spread of an epidemic infectious disease. However, previous studies suggested that SARS-CoV-2 is transmitted within family and hospital-associated populations [3, 11, 12] , indicating that this virus spreads mainly through close contact and infected respiratory droplets rather than through aerosols. In our study, the RNA of SARS-CoV-2 was not detected in any of the 44 air samples, indicating that the possibility of SARS-CoV-2 transmission by aerosols is yet to be confirmed. An air sampler that could force larger volumes of air should be required to detect low concentrations of the virus in the clinical environment in further studies [13] . Conversely, in the designated hospitals for COVID-19, strict measures for air purification had been taken. The most important measure was to open windows to promote ventilation. If mobility could increase air exchange and reduce the virus concentration, then the probability of infection is greatly reduced [14, 15] . Previous studies have shown that ultraviolet light could kill the coronavirus effectively [16] . For rooms with poor ventilation in the designated hospital, an ultraviolet air disinfection machine with 24-h ultraviolet disinfection filtration was devoted to sterilize the air. The Use of keyboard protection films was recommended for easier cleaning and disinfection [17] . The positive rate in medical equipment surfaces such as ventilators, monitors, and X-ray devices was 30.77%, suggesting that the equipment surface can be contaminated with SARS-CoV-2 through infected respiratory secretions of infected patients; these contaminated surfaces caused the spread of the virus to healthcare workers during patient care. Fixed use of equipment for each patient was recommended to prevent cross contamination. Furthermore, all reusable medical equipment should be disinfected thoroughly. One of seven gloves was positive for SARS-CoV-2 RNA. This suggests that healthcare workers can come into contact with the contaminated surfaces mentioned above, and when hand hygiene or glove removal precautions fail, the virus and other microorganisms would spread to other surfaces and/or patients and/or healthcare workers, leading to hospital-associated infections. Hand hygiene is one of the most important measures to prevent the transmission of viruses like SARS-CoV-2 and has been recommended in numerous guidelines. Gloves are not a substitute for hand hygiene [18, 19] . Hand hygiene rules should be strictly observed. Based on the results of our study, it can be concluded that the environment around patients with COVID-19 is widely contaminated. To protect healthcare workers, more thorough infection prevention and control guidelines are needed, as well as delivering methods to prevent contact transmission of COVID-19. Current guidelines suggest gloves, gowns, respirators, and eye protectors as PPE during COVID-19 patient care. There is also need for more careful and comprehensive procedures for putting on and removing PPE [20] . In addition, the basic environmental hygiene and disinfection measures should be put in place [21] . The result may indicate that the usual frequency of disinfection did not meet the demand. The data obtained in our study provided evidence of environmental contamination by SARS-CoV-2 and demonstrated the effectiveness of disinfection. Significant environmental contamination suggests that the environment is a potential medium of transmission [22] . We proposed the following suggestions: (1) environmental surface disinfection should include wiping in an "S"-shaped motion and not repeating the area that has already been cleaned, according to regulations for hospital-associated infection control in the ward of healthcare facilities (WS/T510-2016); (2) the frequency of disinfection should be increased appropriately, at least three times per day: twice during the day and once at night (disinfection should be conducted at any time in case of obvious contamination); and 3) cleaners should be trained repeatedly to ensure that they are qualified for their job. In conclusion, our study demonstrated that environmental surfaces in designated hospitals for patients with COVID-19 were widely contaminated by SARS-CoV-2, suggesting that the environment is a potential medium of transmission. Strict environmental surface hygiene practices should be implemented to prevent healthcare workers from coming into contact with contaminated environmental surfaces, and hand hygiene should be promoted to prevent the spread of virus. 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