ABSTRACT
Objective: To study the infection rate of secondary close contacts of COVID-19 patients, and assess the infection risk in the contacts. Methods: COVID-19 patients' close contacts (with a clear exposure time to index case) with negative nucleic acid test results and secondary close contacts were surveyed in continuous isolation and medical observation in this prospective study. The dynamic nucleic acid test results of the close contacts and secondary contacts of COVID-19 patients were collected to assess their risk of infection. Results: A total of 4 533 close contacts were surveyed, in whom 14 were confirmed as COVID-19 patients with overall secondary attack rate of 0.31%, and 4 201 secondary contacts were tracked, in whom no subsequent infections occurred. Conclusion: Close contacts of COVID-19 patients entered in centralized isolation for medical observation with negative nucleic acid tese results,the secondary close contacts of COVID-19 patients have no risk of infection.
Subject(s)
COVID-19 , Nucleic Acids , COVID-19/epidemiology , Contact Tracing , Humans , Incidence , Prospective Studies , SARS-CoV-2ABSTRACT
The highly infectious and serious nature of coronavirus disease 2019 (COVID-19) has highlighted the need for hospital space disinfection technology and the prevention of human exposure to pathogenic environments. This research developed novel chlorine dioxide (ClO2) sterilization technology to reduce bacteria and viruses in the air and on surfaces. A smart sterilization robot system was also developed to spray disinfectants in operating theaters or patients' rooms, designed according to the results of controlled experiments and the requirements for hospital disinfection. The system was built incorporated a semi-automatic remote-controlled module and an automatic intelligent disinfection function;that is, it could operate independently according to specific epidemic prevention strategies, which were implemented using a combination of Internet of Things (IoT) applications and a gesture recognition function. The elimination of Escherichia coli (E. coli) bacteria on sample plates was 99.8 % effective. This paper reviews the evolution of various disinfection technologies and describes a disinfection robot system in detail.