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1.
Preprint | EuropePMC | ID: ppcovidwho-296845

ABSTRACT

To better understand the development of immunity against SARS-CoV-2 over time, we evaluated humoral and cellular responses a population-based cohort of SARS-CoV-2-infected individuals covering the full spectrum of COVID-19 up to 217 days after diagnosis. We characterized anti-Spike (S)-IgA and -IgG antibody responses in 431 individuals and found that about 85% develop and maintain anti-S-IgG responses over time. In a subsample of 64 participants selected for a detailed characterization of immune responses, we additionally evaluated anti-Nucleocapsid (N)-IgG antibodies and T cell responses specific to viral Membrane (M), N, and S proteins. Most participants had detectable T cell responses to at least one of the four peptide pools analyzed, which were more frequent than antibody seropositivity. We found a moderate correlation between antibody and T cell responses, which declined over time and suggests important variability in response patterns between individuals. The heterogeneity of immune trajectories was further analyzed using cluster analyses taking into account joint antibody and T cell responses over time. We identified five distinct immune trajectory patterns, which were characterized by specific antibody, T cell and T cell subset patterns along with disease severity and demographic factors. Higher age, male sex, higher disease severity and being a non-smoker was significantly associated with stronger immune responses. Overall, the results highlight that there is a consistent and maintained antibody response among most SARS-CoV-2-infected individuals, while T cell responses appear to be more heterogenous but potentially compensatory among those with low antibody responses.

2.
Preprint in English | Other preprints | ID: ppcovidwho-295470

ABSTRACT

Background Longer-term consequences after SARS-CoV-2 infection are becoming an important burden to societies and healthcare systems. Data on post-COVID-19 syndrome in the general population are required for the timely planning of healthcare services and resources. The objective of this study was to assess the prevalence of impaired health status and physical and mental health symptoms among individuals at least six months after SARS-CoV-2 infection, and to characterize their healthcare utilization. Methods This population-based prospective cohort study (Zurich SARS-CoV-2 Cohort) enrolled 431 adults from the general population with polymerase chain reaction-confirmed SARS-CoV-2 infection reported to health authorities between 27 February 2020 and 05 August 2020 in the Canton of Zurich, Switzerland. We evaluated the proportion of individuals reporting not to have fully recovered since SARS-CoV-2 infection, and the proportion reporting fatigue (Fatigue Assessment Scale), dyspnea (mMRC dyspnea scale) or depression (DASS-21) at six to eight months after diagnosis. Furthermore, the proportion of individuals with at least one healthcare contact after their acute illness was evaluated. Multivariable logistic regression models were used to assess factors associated with these main outcomes. Results Symptoms were present in 385 (89%) participants at diagnosis and 81 (19%) were initially hospitalized. At six to eight months, 111 (26%) reported not having fully recovered. 233 (55%) participants reported symptoms of fatigue, 96 (25%) had at least grade 1 dyspnea, and 111 (26%) had DASS-21 scores indicating symptoms of depression. 170 (40%) participants reported at least one general practitioner visit related to COVID-19 after acute illness, and 10% (8/81) of initially hospitalized individuals were rehospitalized. Individuals that have not fully recovered or suffer from fatigue, dyspnea or depression were more likely to have further healthcare contacts. However, a third of individuals (37/111) that have not fully recovered did not seek further care. Conclusions In this population-based study, a relevant proportion of participants suffered from longer-term consequences after SARS-CoV-2 infection. With millions infected across the world, our findings emphasize the need for the timely planning of resources and patient-centered services for post-COVID-19 care. Registration ISRCTN14990068

3.
Int J Public Health ; 66: 1603992, 2021.
Article in English | MEDLINE | ID: covidwho-1533731

ABSTRACT

Objectives: We aimed to evaluate the effectiveness of the SwissCovid digital proximity tracing (DPT) app in notifying exposed individuals and prompting them to quarantine earlier compared to individuals notified only by manual contact tracing (MCT). Methods: A population-based sample of cases and close contacts from the Zurich SARS-CoV-2 Cohort was surveyed regarding SwissCovid app use and SARS-CoV-2 exposure. We descriptively analyzed app adherence and effectiveness, and evaluated its effects on the time between exposure and quarantine among contacts using stratified multivariable time-to-event analyses. Results: We included 393 SARS-CoV-2 infected cases and 261 close contacts. 62% of cases reported using SwissCovid and among those, 88% received and uploaded a notification code. 71% of close contacts were app users, of which 38% received a warning. Non-household contacts notified by SwissCovid started quarantine 1 day earlier and were more likely to quarantine earlier than those not warned by the app (HR 1.53, 95% CI 1.15-2.03). Conclusion: These findings provide evidence that DPT may reach exposed contacts faster than MCT, with earlier quarantine and potential interruption of SARS-CoV-2 transmission chains.


Subject(s)
COVID-19 , Contact Tracing , Mobile Applications , Quarantine , Adult , COVID-19/epidemiology , COVID-19/prevention & control , Cohort Studies , Contact Tracing/methods , Female , Humans , Male , Middle Aged , Mobile Applications/statistics & numerical data , Quarantine/statistics & numerical data , Switzerland/epidemiology , Time Factors
4.
Swiss Med Wkly ; 151(35-36)2021 09 08.
Article in English | MEDLINE | ID: covidwho-1399511

ABSTRACT

​Digital proximity tracing has been promoted as a major technological innovation for its potential added benefits of greater speed, wider reach and better scalability compared with traditional manual contact tracing. First launched in Switzerland on 25 June 2020, the SwissCovid digital proximity tracing app has now been in use for more than one year. In light of this milestone, we raise the questions: What is currently known about the role of SwissCovid in mitigating the pandemic? Were the expectations fulfilled? ​In this review, we will summarise the current state of the literature from empirical studies on the adoption, performance and effectiveness of SwissCovid. The review consists of three sections. The first section summarizes findings from effectiveness studies, which suggest that SwissCovid exposure notifications contributed to preventive actions in 76% of exposure notification recipients and were associated with a faster quarantine time in some SwissCovid user groups. The second describes the public perception and current state of adoption of SwissCovid in Switzerland in light of prevalent misconceptions and overemphasised expectations. the third places the evidence on SwissCovid in an international context. Specifically, we compare key performance indicators of SwissCovid, which are of similar magnitude as for digital proximity tracing apps from other European countries. Using findings from Switzerland, we subsequently derive a preliminary measure of the population-level effectiveness of digital proximity tracing apps. We estimate that exposure notifications may have contributed to the notification and identification of 500 to 1000 SARS-CoV-2-positive app users per month. We explore why this effectiveness estimation is somewhat lower when compared with Germany or the United Kingdom. ​In light of the presented evidence, we conclude that digital proximity tracing works well in specific contexts, such as in mitigating non-household spread. However, future applications of digital proximity tracing should invest into stakeholder onboarding and increased process automatization - without deviating from the principles of voluntariness and user privacy.


Subject(s)
COVID-19 , Mobile Applications , Contact Tracing , Humans , Motivation , SARS-CoV-2
5.
Swiss Med Wkly ; 150: w20281, 2020 May 04.
Article in English | MEDLINE | ID: covidwho-1348747
6.
PLoS One ; 16(7): e0254523, 2021.
Article in English | MEDLINE | ID: covidwho-1305580

ABSTRACT

BACKGROUND: Longer-term consequences after SARS-CoV-2 infection are becoming an important burden to societies and healthcare systems. Data on post-COVID-19 syndrome in the general population are required for the timely planning of healthcare services and resources. The objective of this study was to assess the prevalence of impaired health status and physical and mental health symptoms among individuals at least six months after SARS-CoV-2 infection, and to characterize their healthcare utilization. METHODS: This population-based prospective cohort study (Zurich SARS-CoV-2 Cohort) enrolled 431 adults from the general population with polymerase chain reaction-confirmed SARS-CoV-2 infection reported to health authorities between 27 February 2020 and 05 August 2020 in the Canton of Zurich, Switzerland. We evaluated the proportion of individuals reporting not to have fully recovered since SARS-CoV-2 infection, and the proportion reporting fatigue (Fatigue Assessment Scale), dyspnea (mMRC dyspnea scale) or depression (DASS-21) at six to eight months after diagnosis. Furthermore, the proportion of individuals with at least one healthcare contact after their acute illness was evaluated. Multivariable logistic regression models were used to assess factors associated with these main outcomes. RESULTS: Symptoms were present in 385 (89%) participants at diagnosis and 81 (19%) were initially hospitalized. At six to eight months, 111 (26%) reported not having fully recovered. 233 (55%) participants reported symptoms of fatigue, 96 (25%) had at least grade 1 dyspnea, and 111 (26%) had DASS-21 scores indicating symptoms of depression. 170 (40%) participants reported at least one general practitioner visit related to COVID-19 after acute illness, and 10% (8/81) of initially hospitalized individuals were rehospitalized. Individuals that have not fully recovered or suffer from fatigue, dyspnea or depression were more likely to have further healthcare contacts. However, a third of individuals (37/111) that have not fully recovered did not seek further care. CONCLUSIONS: In this population-based study, a relevant proportion of participants suffered from longer-term consequences after SARS-CoV-2 infection. With millions infected across the world, our findings emphasize the need for the timely planning of resources and patient-centered services for post-COVID-19 care.


Subject(s)
COVID-19/complications , Health Services , Adolescent , Adult , COVID-19/epidemiology , Cohort Studies , Cost of Illness , Depression/epidemiology , Dyspnea/epidemiology , Fatigue/epidemiology , Female , Humans , Male , Middle Aged , Quality of Life , Switzerland , Young Adult
7.
Swiss Med Wkly ; 150: w20457, 2020 12 14.
Article in English | MEDLINE | ID: covidwho-979197

ABSTRACT

In the wake of the pandemic of coronavirus disease 2019 (COVID-19), contact tracing has become a key element of strategies to control the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Given the rapid and intense spread of SARS-CoV-2, digital contact tracing has emerged as a potential complementary tool to support containment and mitigation efforts. Early modelling studies highlighted the potential of digital contact tracing to break transmission chains, and Google and Apple subsequently developed the Exposure Notification (EN) framework, making it available to the vast majority of smartphones. A growing number of governments have launched or announced EN-based contact tracing apps, but their effectiveness remains unknown. Here, we report early findings of the digital contact tracing app deployment in Switzerland. We demonstrate proof-of-principle that digital contact tracing reaches exposed contacts, who then test positive for SARS-CoV-2. This indicates that digital contact tracing is an effective complementary tool for controlling the spread of SARS-CoV-2. Continued technical improvement and international compatibility can further increase the efficacy, particularly also across country borders.


Subject(s)
COVID-19/transmission , Contact Tracing/methods , Disease Notification/methods , Mobile Applications , Smartphone , COVID-19/epidemiology , COVID-19/prevention & control , Confidentiality , Humans , SARS-CoV-2 , Switzerland/epidemiology , Wireless Technology
8.
JMIR Public Health Surveill ; 7(1): e25701, 2021 01 06.
Article in English | MEDLINE | ID: covidwho-978994

ABSTRACT

BACKGROUND: Digital proximity tracing apps have been released to mitigate the transmission of SARS-CoV-2, the virus known to cause COVID-19. However, it remains unclear how the acceptance and uptake of these apps can be improved. OBJECTIVE: This study aimed to investigate the coverage of the SwissCovid app and the reasons for its nonuse in Switzerland during a period of increasing incidence of COVID-19 cases. METHODS: We collected data between September 28 and October 8, 2020, via a nationwide online panel survey (COVID-19 Social Monitor, N=1511). We examined sociodemographic and behavioral factors associated with app use by using multivariable logistic regression, whereas reasons for app nonuse were analyzed descriptively. RESULTS: Overall, 46.5% (703/1511) of the survey participants reported they used the SwissCovid app, which was an increase from 43.9% (662/1508) reported in the previous study wave conducted in July 2020. A higher monthly household income (ie, income >CHF 10,000 or >US $11,000 vs income ≤CHF 6000 or

Subject(s)
COVID-19/psychology , Contact Tracing/instrumentation , Mobile Applications/standards , Physical Distancing , Adult , Aged , COVID-19/complications , COVID-19/transmission , Contact Tracing/trends , Female , Humans , Male , Middle Aged , Mobile Applications/statistics & numerical data , Surveys and Questionnaires , Switzerland
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