In this retrospective cohort study, the housekeepers were monitored for having occupational COVID-19 infection related to their daily practice at COVID-19 ward in addition to the daily practice with UV disinfection robot. The UV disinfection robot was found to be highly effective to protect housekeepers in addition to other precautions including PPE. The two-step cleaning procedure using manual cleaning the patient's room after the UV-robot is a reasonable strategy, while the need for 20 to 30 minutes per room requires good planning of the cleaning services.
Although the hospital housekeepers are on the frontline, little data was available including their status during COVID-19 pandemic. Information about caregivers is usually made up of newspaper clippings or websites (19). Comparing the high-risk procedures, disinfection of the room after the discharge of the patient is not a high-risk procedure. The current recommendations of some paediatric hospitals recommended wearing a mask for any of the personal entering patient room within 30 minutes after discharge, supporting a possible risk for the hospital cleaners (20). According to the CDC, although uncommon, SARS-CoV-2 appears to be airborne especially in the presence of infectious person producing respiratory tract droplets for longer than 30 minutes in an enclosed, non-well ventilated room (21). Regarding this statement, in a daily-day scenario, if a hospital housekeeper who uses an inappropriate PPE enters the patient’s room after a short time after the discharge of a patient with COVID-19, can get SARS-CoV-2 virus. The hybrid UV robots, with appropriate HEPA filters and UV systems in which air passes through, will be effective to clean the air in addition to the cleaning of the environment will help in two ways. In our daily hospital practice, the hybrid UV robot was settled to the middle of the room before any hospital housekeeper enters the patient room for cleaning after the discharge. This strategy of using UV robot in our clinic prevented hospital housekeepers from having symptomatic COVID-19 infections exposure outside the hospital during the COVID-19 pandemic.
Contamination of surfaces that frequent touched in healthcare settings might play role in transmission of the virus (21). Human coronaviruses were reported to remain infectious on inanimate surfaces at room temperature for up to 9 days, however, the exact role of this finding and survival on the hands are not well-known (22). The fact about aerosol production with highly contagious patients, the degree of viral load of SARS-CoV-2 might be an important factor. The World Health Organization recommends ensuring that environmental cleaning and disinfection procedures are followed consistently and correctly. The conventional environmental surfaces cleaning with water and detergent and applying commonly used hospital-level disinfectants (such as sodium hypochlorite) are effective and sufficient procedures (23). Recent studies reported that UV had successfully inactivated the SARS-CoV-2 (13, 29–31) Also, a recent review, suggested common UV disinfection procedures also inactivated and SARS-CoV-2 virus was highly UV sensitive, supporting the usage of UV robots in the daily practice as well (12,21). Moreover, the recent researches had filled a big gap and reported that current regulatory exposure limit (~ 3 mJ/cm2/hour) would result in ~ 90% viral inactivation in ~ 8 minutes, 95% in ~ 11 minutes, 99% in ~ 16 minutes and 99.9% inactivation in ~ 25 minutes (7). In our practice, an average of 20–25 minutes of UV robot was used to ensure the optimal disinfection of the surfaces and the conventional cleaning was performed after the performance of UV robot.
There are some limitations with the study, the COVID-19 infection was screened with the symptom-based (according to the CDC criteria) and no routinely serological tests were performed to demonstrate the asymptomatic infection. Also, the microbiological efficacy tests for UV on SARS-CoV-2 were not testes, and the regulations were done according to the previous reports.
During the COVID-19 pandemic, none of the hospital cleaners got hospital-associated COVID-19 infection. The combination of using PPE properly with strict rules in addition to UV-robot integrated environmental disinfection, is an important strategy to protect health-care workers. The nearly half on hour per one room seems to belong especially for the clinics with high turn-over may harbour time problems, however with a detailed planning and adequate number of UV robots, this problem can be easily solved