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
This article has been Reviewed by the following groups
Listed in
- Evaluated articles (ScreenIT)
Abstract
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.
Article activity feed
-
-
SciScore for 10.1101/2020.09.15.20195396: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement Consent: Health care professionals were asked informed consent for participating in the study prior to digital questionnaire completion.
IRB: The Medical Ethics Committee of the VU University Medical Centre in Amsterdam reviewed the study protocol and confirmed that the study does not fall under the scope of the Medical Research Involving Human Subjects Act.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources The phylogenetic trees were visualized in Figtree. Figtreesuggested: (FigTree, RRID:SCR_008515)All analyses were done using SPSS, … SciScore for 10.1101/2020.09.15.20195396: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement Consent: Health care professionals were asked informed consent for participating in the study prior to digital questionnaire completion.
IRB: The Medical Ethics Committee of the VU University Medical Centre in Amsterdam reviewed the study protocol and confirmed that the study does not fall under the scope of the Medical Research Involving Human Subjects Act.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources The phylogenetic trees were visualized in Figtree. Figtreesuggested: (FigTree, RRID:SCR_008515)All analyses were done using SPSS, version 26 (IBM, Armonk, NY) and Excel. Ethics: Written information about the study was sent out to residents and their legal representatives at May 18th, with the possibility to opt-out. SPSSsuggested: (SPSS, RRID:SCR_002865)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:Limitations: Not all staff members who tested positive participated in the study. In addition, some staff members had to answer the questionnaire retrospectively, which gives the risk of recall bias. Also, the questionnaire did not inquire if staff worked with symptoms. Further, the difference between symptomatic staff and residents could perhaps be explained by the fact that staff was tested less frequent than residents: residents were tested weekly, but staff was tested biweekly. This may have contributed partly to the higher proportion of symptomatic staff. Last, not all SARS-CoV-2 positive samples were sequenced. However, a lot of time points could be analyzed and they show all the same cluster which makes it unlikely that multiple clusters were circulating in the NH. Conclusion: This study suggests that part of the presymptomatic cases in NHs are unrecognized symptomatic cases. Our study supports the guideline of the CDC and ECDC that facility-wide testing of residents and staff needs to be undertaken after the first confirmed SARS-CoV-2 case in the facility. If there is limited viral testing capacity, initial testing of (asymptomatic) close contacts is advised (CDC). This allows identification of possible asymptomatic, presymptomatic cases and unrecognized symptomatic cases and prevent further spread of the virusSequencing should be performed to discriminate ongoing intramural transmission and multiple introductions. Box 1 summarizes the lessons learned during this stud...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
-
