Clinical evaluation of single-swab sampling for rapid COVID-19 detection in outbreak settings in Dutch nursing homes.

PURPOSE: To assess whether one swab can be used to perform both the antigen-detection rapid diagnostic test (Ag-RDT) and reverse transcriptase polymerase chain reaction (RT-PCR) for COVID-19 detection during an outbreak in the nursing home (NH) setting. METHODS: The single-swab method (SSM), where the Ag-RDT is performed with the transport medium used for RT-PCR, was evaluated in three Dutch NHs and compared to the laboratory setting. We collected Ag-RDT and RT-PCR results, NH resident characteristics and symptomatology. In addition, two focus groups were held with the involved care professionals to gain insight into the feasibility of the SMM in the NH setting. RESULTS: In the NH setting, the SSM had a sensitivity of 51% and a specificity of 89% compared to RT-PCR. These were lower than in the laboratory setting (69% and 100% respectively). Yet, when stratified for cycle threshold values, the sensitivity became comparable between the settings. Symptoms occurred more frequent in the Ag-RDT+ group than Ag-RDT- group. Resident characteristics did not differ between these groups. Based on the focus groups, the SSM was feasible to perform if certain requirements, such as availability of staff, equipment and proper training, were met. However, the rapid availability of the test results were perceived as a dilemma. CONCLUSION: The advantages and disadvantages need to be considered before implementation of the SSM can be recommended in the NH setting. For the vulnerable NH residents, it is important to find the right balance between effective testing policy and the burden this imposes.

Dementia and Parkinson's Disease: Risk Factors for 30-Day Mortality in Nursing Home Residents with COVID-19.

BACKGROUND: The COVID-19 pandemic has led to high mortality rates in nursing homes (NHs) in Europe. For adequate risk management and good prognostications, it is essential to identify mortality risk factors. OBJECTIVE: This study aimed to determine whether previously identified risk factors for 30-day mortality in Dutch NH residents with COVID-19 are unique to COVID-19. METHODS: In this cohort study, we included 1,294 NH residents with COVID-19 (cases) and 17,999 NH residents without COVID-19 (controls, from the pre-COVID-19 period). We used descriptive statistics and Cox proportional hazard models to compare mortality rates in residents with and without COVID-19, categorized by risk factors. RESULTS: Cases had a more than 18 times higher hazard of death within 30 days compared to controls (HR 18, 95%CI: 16-20). For residents with COVID-19, being male, having dementia, and having Parkinson's disease (PD) were all associated with a higher 30-day mortality (HR 1.8 versus 1.3 versus 1.7). Being male was also associated with a higher mortality (HR 1.7) in the control group, whereas having dementia and PD were not. COVID-19 symptomatology was very similar for residents with and without dementia or PD, except for delirium and malaise which was more frequent in residents with dementia. CONCLUSION: Dementia and PD were significant additional risk factors for mortality in Dutch NH residents with COVID-19, whereas male gender was not unique to residents with COVID-19. The frailty of PD and dementia in NH residents with COVID-19 are relevant to consider in prognostication, communication, and care planning with residents and their families.

Are presymptomatic SARS-CoV-2 infections in nursing home residents unrecognised symptomatic infections? Sequence and metadata from weekly testing in an extensive nursing home outbreak.

BACKGROUND: Sars-CoV-2 outbreaks resulted in a high case fatality rate in nursing homes (NH) worldwide. It is unknown to which extent presymptomatic residents and staff contribute to the spread of the virus. AIMS: To assess the contribution of asymptomatic and presymptomatic residents and staff in SARS-CoV-2 transmission during a large outbreak in a Dutch NH. METHODS: Observational study in a 185-bed NH with two consecutive testing strategies: testing of symptomatic cases only, followed by weekly facility-wide testing of staff and residents regardless of symptoms. Nasopharyngeal and oropharyngeal testing with RT-PCR for SARs-CoV-2, including sequencing of positive samples, was conducted with a standardised symptom assessment. RESULTS: 185 residents and 244 staff participated. Sequencing identified one cluster. In the symptom-based test strategy period, 3/39 residents were presymptomatic versus 38/74 residents in the period of weekly facility-wide testing (P-value < 0.001). In total, 51/59 (91.1%) of SARS-CoV-2 positive staff was symptomatic, with no difference between both testing strategies (P-value 0.763). Loss of smell and taste, sore throat, headache or myalga was hardly reported in residents compared to staff (P-value <0.001). Median Ct-value of presymptomatic residents was 21.3, which did not differ from symptomatic (20.8) or asymptomatic (20.5) residents (P-value 0.624). CONCLUSIONS: Symptoms in residents and staff are insufficiently recognised, reported or attributed to a possible SARS-CoV-2 infection. However, residents without (recognised) symptoms showed the same potential for viral shedding as residents with symptoms. Weekly testing was an effective strategy for early identification of SARS-Cov-2 cases, resulting in fast mitigation of the outbreak.

Asymptomatic Cases and Limited Transmission of SARS-CoV-2 in Residents and Healthcare Workers in Three Dutch Nursing Homes.

We aimed to assess the contribution of a- and presymptomatic residents and healthcare workers in transmission of SARS-CoV-2 in nursing homes. We conducted two serial point-prevalence surveys, including standardized symptom assessment and nasopharyngeal and oropharyngeal testing for SARS-CoV-2, among 297 residents and 542 healthcare workers of three Dutch nursing homes (NHs) with recent SARS-CoV-2 introduction. At the first point-prevalence survey, 15 residents tested positive of which one was presymptomatic and three remained asymptomatic. At the second point-prevalence survey one resident and one healthcare worker tested SARS-CoV-2 positive and both remained asymptomatic. Although a limited number of SARS-CoV-2 positive cases were identified, this study confirms a- and presymptomatic occurrence of Covid-19. We additionally describe factors that may contribute to the prevention of transmission. Taken together, our study complements the discussion on effective SARS-CoV-2 screening in NHs.

Clinical Suspicion of COVID-19 in Nursing Home Residents: Symptoms and Mortality Risk Factors.

OBJECTIVES: To describe the symptomatology, mortality, and risk factors for mortality in a large group of Dutch nursing home (NH) residents with clinically suspected COVID-19 who were tested with a reverse transcription-polymerase chain reaction (RT-PCR) test. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: Residents of Dutch NHs with clinically suspected COVID-19 and who received RT-PCR test. METHODS: We collected data of NH residents with clinically suspected COVID-19 via electronic health records between March 18 and May 13, 2020. Registration was performed on diagnostic status [confirmed (COVID-19+)/ruled out (COVID-19-)] and symptomatology (typical and atypical symptoms). Information on mortality and risk factors for mortality were extracted from usual care data. RESULTS: In our sample of residents with clinically suspected COVID-19 (N = 4007), COVID-19 was confirmed in 1538 residents (38%). Although symptomatology overlapped between residents with COVID-19+ and COVID-19-, those with COVID-19+ were 3 times more likely to die within 30 days [hazard ratio (HR), 3.1, 95% confidence interval (CI) 2.7-3.6]. Within this group, mortality was higher for men than for women (HR 1.8, 95% CI 1.5-2.2), and we observed a higher mortality for residents with dementia, reduced kidney function, and Parkinson's disease, even when corrected for age, gender, and comorbidities. CONCLUSIONS AND IMPLICATIONS: About 40% of the residents with clinically suspected COVID-19 actually had COVID-19, based on the RT-PCR test. Despite an overlap in symptomatology, mortality rate was 3 times higher for residents with COVID-19+. This emphasizes the importance of using low-threshold testing in NH residents, which is an essential prerequisite to using limited personal protective equipment and isolation measures efficiently.