Risk factors and risk groups

(Latest update 30 September 2021)

ECDC’s weekly COVID-19 country overview presents age-specific COVID-19 case notification rates, death rates, and vaccination uptake by country, based on data for confirmed COVID-19 cases reported by EU/EEA countries to The European Surveillance System (TESSy). ECDC’s weekly COVID-19 surveillance report uses data from countries that have reported relevant case-level information throughout the pandemic to estimate age-, age-sex specific risk, and changes over time in those risks, for hospitalisation, severe hospitalisation, and death.

Several underlying conditions have a significant independent effect on severe COVID-19 outcomes. Severity of COVID-19 is associated with increased age,  pre-existing medical conditions and the male sex [1-3]. Underlying health conditions reported among adult patients with severe COVID-19 disease include diabetes [4-6], obesity [4,7], hypertension [3,4], history of heart failure[4,8], ischaemic heart disease [4,17,18], solid organ tumours [4,9], chronic obstructive pulmonary disease (COPD) [4,10], chronic respiratory disease[4], chronic kidney disease [4,11,12], immune compromised status [4], cancer [4,13,14], neurological conditions [4,15], smoking [4,16], and pregnancy [14,17]. Severe disease is here defined as admission to hospital/intensive care unit (ICU), mechanical ventilation, or death.

With regard to mortality among hospitalised COVID-19 cases, high-certainty evidence in age-/sex-adjusted analyses has identified diabetes mellitus, renal disease and dementia as significant risk factors for mortality. Furthermore, there is moderate certainty evidence that ischaemic heart disease, stroke, solid organ tumours and obesity are also risk factors. Mortality among cases detected in the community setting is associated with a history of heart failure, stroke, diabetes, and end-stage renal disease. There is high-or-moderate certainty evidence of an association between hospitalisation for COVID-19 and diabetes, heart failure, COPD, renal disease, obesity, and ischaemic heart disease in the community setting [4].

Age is a very important predictor of severe COVID-19. The risk of severe outcomes increases sharply with increasing age, even after controlling for other potential confounding factors, including sex and underlying conditions. Age is also an important effect modifier in the associations between certain underlying conditions and severe COVID-19 outcomes. While some pre-existing medical conditions are known risk factors for severe disease and ICU admission in all age groups, including children and adolescents [18-20,21], it is still not fully understood how these pre-existing conditions influence the course of COVID-19. The absolute probability of being hospitalised or dying increases with age, but findings indicate that for some conditions a younger person may have the same or an even higher probability of severe outcome than an older person without these conditions. This is relevant for age and risk-factor based prioritisation of vaccination, particularly in the young [22].

Residents of long term care facilities and nursing homes

(last update 14/11/2020)

Residents of long-term care facilities (LTCFs) are a medically and socially vulnerable group. Medically vulnerable people in the context of this analysis are those with an elevated risk of severe disease and death due to COVID-19. These include, but are not limited to, older people (aged 60 years and above) including those living in long-term care facilities, and people with underlying health conditions [23,24].

European countries that have established surveillance systems in LTCFs have reported that 5-6% of all LTCF residents died of COVID-19, and that LTCF residents accounted for up to 72% of all COVID-19 related deaths (Table) [25,26].

COVID-19 outbreaks in LTCFs can have devastating effects, since the residents are already vulnerable due to their age and frequent underlying health problems, meaning that there is a high likelihood of unfavourable outcomes [27].

Socially vulnerable groups include individuals who are more liable to suffer from the consequences of the measures imposed (feelings of abandonment, loneliness), while being less able to comply with them due to their living conditions [24,28]. Furthermore, social vulnerability in LCTF residents may be exacerbated when non-pharmaceutical interventions are in place that limit physical personal interactions or impact access to health services [28,29].

The rapid spread of SARS-CoV-2 within and between LTCFs is fuelled by the transmission dynamics of COVID-19, including the potential for asymptomatic transmission amongst and between staff and residents [25,27,30,31]. 

Factors that have hampered the response to COVID-19 in LTCFs have included insufficient availability of personal protective equipment (PPE) and human resources; insufficient training in infection prevention and control (IPC) including use of PPE and case management; and the possible reduced access to essential healthcare services [29,30,32-37]. Furthermore, there are substantial differences in the organisation of long-term care between and within European countries, affecting infectious disease preparedness and response in LTCFs. These were well documented by the European Social Policy Network (ESPN), in its 2018 report for the European Commission Directorate General for Employment, Social Affairs and Inclusion [35], and in the country-level reports summarised in that document [36]. The report analyses ‘the four main challenges which are common to all European countries: the access and adequacy of long-term care provision, the quality of formal home care as well as residential services, the employment of informal carers, and the financial sustainability of national long-term care systems. A WHO policy objective for mitigation of the impact of COVID-19 across long-term care recommends that countries ‘initiate steps for the transformation of health and long-term care systems to appropriately integrate and ensure continuous, effective governance of long-term care services’ [37].

Further information on ECDC’s options for intervention to prevent transmission and implement testing strategies can be found in the following documents:

  • ‘Infection prevention and control and preparedness for COVID-19 in healthcare settings’ [29];
  • ‘Surveillance of COVID-19 in long-term care facilities in the EU/EEA’[32];
  • ‘COVID-19 testing strategies and objectives’ [38];
  • ‘Guidelines for the implementation of non-pharmaceutical interventions against COVID-19’ [28].
  • ‘Guidance for discharge and ending isolation of people with COVID-19’ [39].

There is also an increased risk of severe COVID-19 impact in other similar settings with medically and socially vulnerable persons. These include hospital long-term care wards, hostels (without any type of nursing care), sheltered care homes, day centres, home-based centres, and facilities for protected living. These settings may require specific interventions, but if special provisions are not available, guidance for long-term care facilities and community care can be consulted. ECDC’s document ‘Guidance on the provision of support for medically and socially vulnerable populations in EU/EEA countries and the United Kingdom during the COVID-19 pandemic’ [40] contains considerations for institutions supporting the homeless and people with alcohol or drug dependence.

For more information and resources, see Prevention and control of COVID-19 in long-term care facilities.