Covid-19: standard of living, housing type, origin… These other risk factors for severe forms

An elderly man, with a low standard of living, living in a small social housing, and born in an African country. This is the typical profile of the patient most at risk for a severe form of Covid-19 if infected, according to a comprehensive study by the Department of Research, Studies, Evaluation and Statistics (Drees), published this morning. The databases SI-VIC (the number of Covid patients hospitalized) and Fidéli (the INSEE demographic file on housing and individuals) were compared.

We already knew that age, gender and co-morbidities were important risk factors. This work, performed in mainland France on the period from March 2020 to November 2021, also refer to socio-economic characteristics. Here’s what you need to remember.

Age, the “dominant” factor.

This research confirms it: the elderly are much more at risk of a severe form than young people. The over-60s represent 72% of hospitalized patients, but only 27% of the population. Gender also plays a role, but to a lesser extent: 52% of hospitalized patients over 60 are male, compared to 45% of residents in this age group.

Quality of life

The average standard of living of hospitalized patients is 6% lower than that of the general population. The overrepresentation of the most modest is more evident in the young than in the elderly. If we limit ourselves to 35-49 year olds, the hospitalization rate for the least fortunate is 20% 1.6 times higher than the average. This ratio is 1.5 among the 50-74 year-olds and 1.2 among the over-75s.

These differences can be explained by several factors: poorer health status, more frequent co-morbidities, exposed occupations and thus a risk of contamination, etc. “This income effect may reflect living and working conditions associated with an increased risk of exposure to the virus, as well as a more frequent presence of co-morbidities in the most underprivileged”, summarizes de Drees.

Housing density, “great result”

The type of housing also emerges as a determining criterion. While 15% of the inhabitants of France live in social housing, this is the case for 21% of the hospitalized patients. By focusing on the 35-49 year olds, we come across 16% of the inhabitants and 29% of the seriously ill patients living in social housing. According to the model that takes into account several factors, living in social housing multiplies the risk of hospitalization by 1.5.

Another indicator: the surface area per inhabitant. The smaller it is, the greater the risk of hospitalization, regardless of age group. For example, 25% of 35-49 year olds have less than 20 m² to live in (either alone or in shared housing), but this is the case for 37% of hospitalized patients. With similar characteristics, people with an area of ​​between 40 and 60 m² to live in have a reduced risk of hospitalization of 0.8 compared to people who live in cramped accommodation (less than 20 m² for each).

People born in Africa, especially at risk

Here too the conclusion is clear. 17% of patients aged at least 35 who are hospitalized were born in an African country, compared to 9% of residents. This over-representation can be explained by lower living standards among immigrants, but also by the fact that certain areas with the most foreign-born residents, such as Seine-Saint-Denis, have been particularly affected by this Covid pandemic.

Being born in the Maghreb increases the risk of being hospitalized by 1.7 compared to being born in France, the DREES indicates. This relative risk is slightly lower (1.6) for people born elsewhere in Africa.

Inequality reinforced by vaccination?

The link between a low standard of living and a high risk of hospitalization appears to be stronger during the fourth wave, in the summer of 2021, than during the previous one. At that time, however, 70% of the French population had already been vaccinated. But with great variations. For example, several studies have shown that vaccination rates were higher in the higher social classes than in the low standard of living.

The DREEs have therefore processed the vaccination data provided by Medicare. “The idiosyncrasy of the fourth wave, which affects especially the most modest, could reflect the uneven distribution of vaccination rates in the population, or the overexposure associated with living and working conditions, exacerbated by the greater infectivity of the Delta. variant.”, she says.