Epidemiologic and Genomic Analysis of SARS-CoV-2 Delta Variant Superspreading Event in Nightclub, the Netherlands, June 2021.

We report a severe acute respiratory syndrome coronavirus 2 superspreading event in the Netherlands after distancing rules were lifted in nightclubs, despite requiring a negative test or vaccination. This occurrence illustrates the potential for rapid dissemination of variants in largely unvaccinated populations under such conditions. We detected subsequent community transmission of this strain.

Implementation of a national testing policy in Dutch nursing homes during SARS-CoV-2 outbreaks.

BACKGROUND: To evaluate how a national policy of testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) regardless of symptoms was implemented during outbreaks in Dutch nursing homes in the second wave of the pandemic and to explore barriers and facilitators to serial testing. METHODS: We conducted a mixed-method study of nursing homes in the Netherlands with a SARS-CoV-2 outbreak after 15 September 2020. Direct care staff and management from 355 healthcare organizations were invited to participate in a digital survey. A total of 74 out of 355 (20.9%) healthcare organizations participated and provided information about 117 nursing homes. We conducted 26 in-depth interviews on the outbreak and the testing strategy used. We also conducted four focus group meetings involving managers, physicians, nurses, and certified health assistants. Recordings were transcribed and data were thematically analyzed. RESULTS: One hundred and four nursing homes (89%) tested residents regardless of their symptoms during the outbreak, and 85 nursing homes (73%) tested the staff regardless of their symptoms. However, interviews showed testing was sometimes implemented during later stages of the outbreak and was not always followed up with serial testing. Barriers to serial testing regardless of symptoms were lack of knowledge of local leaders with decisional making authority, lack of a cohort ward or skilled staff, and insufficient collaboration with laboratories or local public health services. Important facilitators to serial testing were staff willingness to undergo testing and the availability of polymerase chain reaction (PCR) tests. CONCLUSIONS: Serial testing regardless of symptoms was only partially implemented. The response rate of 21% of nursing home organizations gives a risk of selection bias. Barriers to testing need to be addressed. A national implementation policy that promotes collaboration between public health services and nursing homes and educates management and care staff is necessary.

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.