Etiologic and prognostic roles of frailty, multimorbidity and socioeconomic characteristics in the development of SARS-CoV-2 infection and related severe health outcomes: systematic reviews of population-based studies

Abstract The study had 2 objectives, to: 1) evaluate the etiologic roles of frailty, multimorbidity and socioeconomic status on SARS-CoV-2 infection probability, hospitalization, intensive care unit (ICU) admission, mechanical ventilation and COVID-19 related mortality; 2) investigate the prognostic roles of mentioned risk factors on the likelihood of hospitalization, ICU admission, mechanical ventilation, COVID-19 mortality, functioning, quality of life, disability, mental health and work absence. Three systematic reviews were performed, for each risk factor. The reviews shared first screening steps relying on a common population-based approach. Initial search took place on 7 April 2021 in PubMed, Embase, PsycINFO and WHO Covid-19 database. An update was performed for frailty only, on 1 February 2022, due to the scarce literature retained initially. Prospero registration number: CRD42021249444. Initial search retrieved 10 139 records; 411 studies were read in full text. An update for frailty retrieved 565 records. Finally, the total number of included studies was: for multimorbidity, objective 1 N = 2, objective 2 N = 13; frailty, objective 1 N = 2, objective 2 N = 3; socioeconomic characteristics, objective 1 N = 57, objective 2 N = 30. The risk of severe short-term outcomes such as mortality, ICU admission or hospitalization increased with increasing disease burden and socioeconomic deprivation. Literature on long-term impacts was not identified. The evidence indicates a dose-effect association across all risk factors and outcomes. There is a lack of work conducted on population-based representative samples accounting for frailty and multimorbidity. Measures of multimorbidity and frailty were heterogeneous between studies. Most of the studies observing socioeconomic determinants were performed in the USA and the UK; hence the need for more research in different contexts. Further evidence is required in order to estimate the impact of crisis among general population.

The study had 2 objectives, to: 1) evaluate the etiologic roles of frailty, multimorbidity and socioeconomic status on SARS-CoV-2 infection probability, hospitalization, intensive care unit (ICU) admission, mechanical ventilation and COVID-19 related mortality; 2) investigate the prognostic roles of mentioned risk factors on the likelihood of hospitalization, ICU admission, mechanical ventilation, COVID-19 mortality, functioning, quality of life, disability, mental health and work absence. Three systematic reviews were performed, for each risk factor. The reviews shared first screening steps relying on a common population-based approach. Initial search took place on 7 April 2021 in PubMed, Embase, PsycINFO and WHO Covid-19 database. An update was performed for frailty only, on 1 February 2022, due to the scarce literature retained initially. Prospero registration number: CRD42021249444. Initial search retrieved 10 139 records; 411 studies were read in full text. An update for frailty retrieved 565 records. Finally, the total number of included studies was: for multimorbidity, objective 1 N = 2, objective 2 N = 13; frailty, objective 1 N = 2, objective 2 N = 3; socioeconomic characteristics, objective 1 N = 57, objective 2 N = 30. The risk of severe short-term outcomes such as mortality, ICU admission or hospitalization increased with increasing disease burden and socioeconomic deprivation. Literature on long-term impacts was not identified. The evidence indicates a dose-effect association across all risk factors and outcomes. There is a lack of work conducted on population-based representative samples accounting for frailty and multimorbidity. Measures of multimorbidity and frailty were heterogeneous between studies. Most of the studies observing socioeconomic determinants were performed in the USA and the UK; hence the need for more research in different contexts. Further evidence is required in order to estimate the impact of crisis among general population.

Background:
Contact tracing is a public health intervention implemented in synergy with other measures, such as testing, physical distancing, and vaccination, to curb the COVID-19 pandemic. Digital solutions have been developed worldwide to enhance the contact tracing process. The aim of the study was to evaluate the effectiveness and impact of tracking COVID-19 patients using digital tools.

Methods:
A systematic literature review was performed on eight online databases to identify observational studies on digital contact tracing, published 2020-2021, in English. Studies identified through the 'Population Health Information Research Infrastructure' project were also included. An ad hoc form has been deployed for data extraction of relevant information. Quality assessment of the included studies will be performed using validated tools.

Results:
Over 8000 records were identified, of which 27 met the inclusion criteria: 16 modelling and 11 population-based studies. A study was based on GPS technology, four were Bluetooth-based, and others used digital technologies and manual tracing. The uptake rate of the tools ranged 19-100% across the studies. Most studies compared digital contact tracing with other strategies (e.g., no intervention, lockdown). Digital contact tracing was associated with improved identification of contact persons (9 studies), reduction of the effective reproduction number or covid-19 infections (8 studies), and increased effectiveness in combination with other containment measures (9 studies). Security and privacy issues were considered in 8 studies.

Conclusions:
Digital contact tracing contributes in reducing further transmission, especially with sufficient population uptake of the applications and in combination with other public health measures. However, its deployment has been limited by security and privacy issues. Further studies are required to investigate the combined impact of digital and conventional contact tracing and enhance privacy and security.
iii30 European Journal of Public Health, Volume 32 Supplement 3, 2022