The Corona Immunitas Digital Follow-Up eCohort to Monitor Impacts of the SARS-CoV-2 Pandemic in Switzerland: Study Protocol and First Results

Speierer, Alexandre; Chocano-Bedoya, Patricia; Anker, Daniela; Schmid, Alexandra; Keidel, Dirk; Vermes, Thomas; Imboden, Medea; Levati, Sara; Franscella, Giovanni; Corna, Laurie; Amati, Rebecca; Harju, Erika; Luedi, Chantal; Michel, Gisela; Veys-Takeuchi, Caroline; Zuppinger, Claire; Nusslé, Semira Gonseth; D’Acremont, Valérie; Tall, I; Salberg, Éric; Baysson, Hélène; Lorthe, Elsa; Pennacchio, Francesco; Frei, Anja; Kaufmann, Marco; Geigges, Marco; West, Erin; Schwab, Nathalie; Cullati, Stéphane; Kahlert, Christian; Stringhini, Silvia; Vollrath, Fabian; Probst‐Hensch, Nicole; Rodondi, Nicolas; Puhan, Milo A.; Wyl, Viktor von

doi:10.3389/ijph.2022.1604506

Cited by 17 publications

(18 citation statements)

References 14 publications

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“…Furthermore, relevant actions for transmission prevention were also quite frequently reported, as almost 3 out of 4 exposure-notified SwissCovid app users reported getting tested or having entered quarantine during the Omicron variant phase. These estimates fall in line with other studies using the same [ 28 ] or different Swiss survey databases [ 29 ]. However, they could be prone to reporting biases, such as social desirability bias, characterized as the tendency of survey respondents to answer questions in a manner that will be viewed favorably by others.…”

Section: Discussionsupporting

confidence: 92%

Performance of the Swiss Digital Contact-Tracing App Over Various SARS-CoV-2 Pandemic Waves: Repeated Cross-sectional Analyses

Daniore¹,

Nittas²,

Menges³

et al. 2022

JMIR Public Health Surveill

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Background Digital proximity-tracing apps have been deployed in multiple countries to assist with SARS-CoV-2 pandemic mitigation efforts. However, it is unclear how their performance and effectiveness were affected by changing pandemic contexts and new viral variants of concern. Objective The aim of this study is to bridge these knowledge gaps through a countrywide digital proximity-tracing app effectiveness assessment, as guided by the World Health Organization/European Center for Prevention and Disease Control (WHO/ECDC) indicator framework to evaluate the public health effectiveness of digital proximity-tracing solutions. Methods We performed a descriptive analysis of the digital proximity-tracing app SwissCovid in Switzerland for 3 different periods where different SARS-CoV-2 variants of concern (ie, Alpha, Delta, and Omicron, respectively) were most prevalent. In our study, we refer to the indicator framework for the evaluation of public health effectiveness of digital proximity-tracing apps of the WHO/ECDC. We applied this framework to compare the performance and effectiveness indicators of the SwissCovid app. Results Average daily registered SARS-CoV-2 case rates during our assessment period from January 25, 2021, to March 19, 2022, were 20 (Alpha), 54 (Delta), and 350 (Omicron) per 100,000 inhabitants. The percentages of overall entered authentication codes from positive tests into the SwissCovid app were 9.9% (20,273/204,741), 3.9% (14,372/365,846), and 4.6% (72,324/1,581,506) during the Alpha, Delta, and Omicron variant phases, respectively. Following receipt of an exposure notification from the SwissCovid app, 58% (37/64, Alpha), 44% (7/16, Delta), and 73% (27/37, Omicron) of app users sought testing or performed self-tests. Test positivity among these exposure-notified individuals was 19% (7/37) in the Alpha variant phase, 29% (2/7) in the Delta variant phase, and 41% (11/27) in the Omicron variant phase compared to 6.1% (228,103/3,755,205), 12% (413,685/3,443,364), and 41.7% (1,784,951/4,285,549) in the general population, respectively. In addition, 31% (20/64, Alpha), 19% (3/16, Delta), and 30% (11/37, Omicron) of exposure-notified app users reported receiving mandatory quarantine orders by manual contact tracing or through a recommendation by a health care professional. Conclusions In constantly evolving pandemic contexts, the effectiveness of digital proximity-tracing apps in contributing to mitigating pandemic spread should be reviewed regularly and adapted based on changing requirements. The WHO/ECDC framework allowed us to assess relevant domains of digital proximity tracing in a holistic and systematic approach. Although the Swisscovid app mostly worked, as reasonably expected, our analysis revealed room for optimizations and further performance improvements. Future implementation of digital proximity-tracing apps should place more emphasis on social, psychological, and organizational aspects to reduce bottlenecks and facilitate their use in pandemic contexts.

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Section: Discussionsupporting

confidence: 92%

Performance of the Swiss Digital Contact-Tracing App Over Various SARS-CoV-2 Pandemic Waves: Repeated Cross-sectional Analyses

Daniore¹,

Nittas²,

Menges³

et al. 2022

JMIR Public Health Surveill

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“…CIT is part of Corona Immunitas (CI), a nationwide research program led by the Swiss School of Public Health (SSPH+) [14]. Detailed information about the study design is reported elsewhere [14,15].…”

Section: Methodsmentioning

confidence: 99%

Prevalence and association of frailty with SARS-CoV-2 infection in older adults in Southern Switzerland—Findings from the Corona Immunitas Ticino Study

Jiang

Corna

Amati

et al. 2022

Preprint

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Background Frailty is an age-associated state of increased vulnerability to stressors that strongly predicts poor health outcomes. Epidemiological evidence on frailty is limited during the COVID-19 pandemic, and whether frailty is associated with the risk of infection is unknown. Objectives We derived a robust Frailty Index (FI) to measure the prevalence of frailty and its risk factors in community-dwelling older adults in Southern Switzerland (Ticino), and we explored the association between frailty and serologically confirmed SARS-CoV-2 infection. Methods In September 2020, we recruited a random sample of community-dwelling older adults (65+) in the Corona Immunitas Ticino prospective cohort study (CIT) and assessed a variety of lifestyle and health characteristics. We selected 30 health-related variables, computed the Rockwood FI, and applied standard thresholds for robust (FI < 0.1), pre-frail (0.1 ≤ FI < 0.21), and frail (FI ≥ 0.21). Results Complete data for the FI was available for 660 older adults. The FI score ranged between zero (no frailty) and 0.59. The prevalence of frailty and pre-frailty were 10.3% and 48.2% respectively. The log-transformed FI score increased by age similarly in males and females, on average by 2.8% (p < 0.001) per one-year increase in age. Out of 481 participants with a valid serological test, 11.2% were seropositive to either anti-SARS-CoV-2 IgA or IgG. The frailty status and seropositivity were not statistically associated (p = 0.236). Conclusion Advanced age increases the risk of frailty. The risk of COVID-19 infection in older adults may not differ by frailty status.

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“…This prospective population based multi-region cohort study is part of the Corona Immunitas research programme in Switzerland 16,17 , for which we had completed four phases of seroprevalence studies between April 2020 and October 2021 using a standardised protocol. The current study includes results from phases five and six, for which assessments were conducted between 1 March and 1 April 2022 and 30 May and 11 July, respectively.…”

Section: Study Design Sampling and Participantsmentioning

confidence: 99%

Development of hybrid immunity during a period of high incidence of infections with Omicron subvariants: A prospective population based multi-region cohort study

Frei

Kaufmann

Amati

et al. 2022

Preprint

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Background Seroprevalence and the proportion of people with neutralizing activity against SARS-CoV-2 variants was high in early 2022. Since it is unclear how immunity in the general population evolves, the aim of this study was to assess the development of functional and hybrid immunity in the general population during a period of high incidence of infections with Omicron variants. Methods This prospective population based multi-region cohort study is part of the Corona Immunitas research programme in Switzerland. In March 2022, we randomly selected individuals from the general population in southern (canton of Ticino) and north-eastern (canton of Zurich) Switzerland, who were assessed again in June/July 2022. We supplemented the June/July 2022 sample with a random sample from western Switzerland (canton of Vaud). We assessed SARS-CoV-2 specific IgG antibodies against spike and nucleocapsid proteins and the presence of SARS-CoV-2 neutralising antibodies against three variants (wildtype, Delta, Omicron). Findings In June/July 2022, seroprevalence was >98% in 2553 individuals from the general Swiss population. The proportion of individuals with neutralising antibodies against wildtype, Delta, and Omicron was 94.2%, 90.8%, and 84.9%, and at least 51% of the participants developed hybrid immunity. Individuals with hybrid immunity had, compared to those with only vaccine- or infection-induced immunity, highest levels of both, anti-spike IgG antibodies titres (4518 vs. 4304 vs. 269 WHO U/ml) and neutralisation capacity against wildtype (99.8% vs. 98% vs. 47.5%), Delta (99% vs. 92.2% vs. 38.7%), and Omicron (96.4% vs. 79.5% vs. 47.5%). Interpretation This first study on functional and hybrid immunity in the general population after Omicron waves showed that SARS-CoV-2 has become endemic. The high levels of antibodies and neutralization in the general populations support the emerging recommendations of some countries where booster vaccinations are still strongly recommended for vulnerable persons but less strongly recommended for individuals in the general population.

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The Corona Immunitas Digital Follow-Up eCohort to Monitor Impacts of the SARS-CoV-2 Pandemic in Switzerland: Study Protocol and First Results

Cited by 17 publications

References 14 publications

Performance of the Swiss Digital Contact-Tracing App Over Various SARS-CoV-2 Pandemic Waves: Repeated Cross-sectional Analyses

Performance of the Swiss Digital Contact-Tracing App Over Various SARS-CoV-2 Pandemic Waves: Repeated Cross-sectional Analyses

Prevalence and association of frailty with SARS-CoV-2 infection in older adults in Southern Switzerland—Findings from the Corona Immunitas Ticino Study

Development of hybrid immunity during a period of high incidence of infections with Omicron subvariants: A prospective population based multi-region cohort study

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