## 5 Conclusions  
UV-SAN is a sanitation system based on UVC radiation that can be installed inside ambulances and that is able, in a short time, to carry out an effective, safe and sustainable sanitation of the patient's compartment.  
The effectiveness of the UVC radiation has been successfully tested both against SARS-CoV-2, and MDR bacteria. Experimental tests have shown that UVC radiation is effective in 10 min to reduce SARS-CoV-2 viral load to undetectable level, moreover the UVC light can be efficiently implemented in the UV-SAN system for the sanitation of ambulance compartments where it was validated against MDR bacteria. Due to the precautions required by the Biosafety Level (BSL-3) for testing a pathogen, such as SARS-CoV-2, it is a standard technique to use surrogate species as a reference to higher BSL species, including bacteria [49,50]. Thus, it could be assume that the efficacy results obtained on the ambulance with MDR bacteria, could be extrapolated to the SARS-CoV-2.  
The ease of use and the short irradiation time is compatible with the daily routine apply use even during periodic downtime (i.e., patient transfer, waiting after patient offload). These aspects were also verified during a pilot stage directly on the ambulance started in June 2021. The daily use has shown that the system does not need additional efforts by the operators. The automatic recording of the sanitation process allows the Ambulance Manager to have a real-time and full control of sanitation level and to retrieve this information, needed to accomplish administrative and legal duties, in a short time and with a high level of confidence. In fact, the traceability process is fully automatized without the intervention of the healthcare operator, guaranteeing the truthfulness of the data.  
These data are encouraging and indicate that UV-SAN can be used as a complementary sanitization system in addition to the current cleaning methods to increase the level of sanitation, to prevent the accidental spread of pathogens and to reduce the risk of an infections.  
The threatening spread of MDR bacteria inside hospitals urges us to look for new solutions, in order to minimize the risk for patients and health care workers, thus although the UV-SAN System has been designed and optimized to work in ambulances, considering the time required for sanitation and ease of use, it can find applications in other healthcare environment.  
Conceptualization, Z.M. and P.P.; methodology, Z.M. and P.P.; software, P.P.; culture, isolation and titration of SARS-CoV-2, Z.M., C.M., M.B., A.M., L.S., S.A. and F.M.; writing--original draft preparation, Z.M.; writing--review and editing, A.C., M.A., A.G., M.B. and F.M.; supervision, E.R. and A.R.; project administration, P.P., F.A., M.M., E.R. and A.R.; funding acquisition, P.P. All authors have read and agreed to the published version of the manuscript.  
This research was co-funded by the European Space Agency in the frame of the Business Applications program, through the Announcement of Opportunity \"Space in response to COVID-19 outbreak\". Reference: AO/1-10314/20/NL/AF.  
Not applicable.  
The authors are grateful to [PERSON] for secretarial assistance and [PERSON], [PERSON] and [PERSON] for technical support.  
The authors declare that the funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.