Local epidemiology of the SARS-COV 2 pandemic in nursing homes: A Swiss experience

Introduction: The SARS-CoV-2 pandemic has affected many nursing homes (NH)s. Residents are more susceptible to coronavirus disease 2019 (COVID-19) complications due to their age, dependency and sometimes their psychiatric illness. Early identification and care positive residents are a powerful approach to limit the spread of the virus. Objectives: This study aims to: i) assess the spread of SARS-CoV-2 by collecting data on the NH of the resident and their microbiologic data in order to control the transmission of the virus. ii) improve the nursing practices of infection control and to adapt the preventive strategies. Methods: Data were collected from the register of the cantonal office of public health Vaud, from the NH staff, or from an on-line reporting platform. Immediately upon identification of a case, a cantonal nurse specialized in infection prevention and control (IPC) speaks with the NH staff or visits the NH. The IPC nurse recommended IPC measures and the screening strategy to control an outbreak. A daily or a biweekly follow-up was required until the resolution of the outbreak. When the NH has no more isolated COVID-19 positive resident, we wrote a final report. Results: The first wave of the COVID-19 pandemic in NHs lasted from 09.03.2020 to 23.06.2020. 62 NHs/163 have been affected, 38% of NHs in the canton. The mean attack rate was 16% (1-62%). About 700/5178 residents (14%) have been infected by COVID-19: 400 residents with a laboratory confirmation of infection while 300 were clinical suspicions of COVID-19. There were 5% of deaths (255/5178). The second wave lasted from 10.08.2020 to 31.12.2020. 104NHs/163 (64%) have been affected. The mean attack rate was 38% (6-91%). 1914/5178 (37%) residents have been infected by the virus;more than twice as much as the first wave. The rate of death of the second wave was 8% (426/5178). The mean duration of outbreak cases was 5 weeks (2-10 Weeks). Conclusion: NHs have been highly impacted by the second wave. The systematic screening for SARS-Cov-2 was crucial in detecting asymptomatic residents. The implementation of adequate IPC measures, the NH collaboration and the interventions of IPC nurses were a successful approach to limit the spread of the virus. Knowledge of NH staff in IPC was improved.