Table 4 Multivariate logistic regression analyses to characterize factors associated with the outcomes of interest.

Model 1. Perceived risk of developing COVID-19

Log likelihood = − 330.14; χ² = 190.43 (14 df); p < 0.0001

Older

1.06

0.01

1.04–1.08

 < 0.001

Being affected by chronic diseases

2.68

0.6

1.73–4.16

 < 0.001

Reporting at least one common symptom compatible with COVID-19 in the previous 3 months

1.55

0.33

1.03–2.35

0.037

Poor knowledge about effective infection control measures for COVID-19

0.56

0.14

0.34–0.92

0.023

Believing that COVID-19 will cause serious consequences in their prison

3.12

1.07

1.59–6.12

0.001

Perceiving to be at high risk of severe complications caused by COVID-19

2.4

0.73

1.32–4.35

0.004

Believing that COVID-19 will continue to spread in Italy

1.86

0.41

1.21–2.86

0.005

Institution

Prison 1

1^a

Prison 2

0.67

0.14

0.43–1.02

0.062

Married/cohabitant

1.37

0.3

0.89–2.1

0.152

Not having sons/daughters

0.67

0.18

0.39–1.14

0.142

Having had depression symptoms

1.55

0.38

0.96–2.51

0.075

Having had generalized anxiety symptoms

1.24

0.31

0.76–2.01

0.392

Not having received information about COVID-19 from family and friends

0.75

0.15

0.5–1.12

0.159

Need of additional information about COVID-19

1.42

0.34

0.88–2.27

0.149

Model 2. Self-confidence about the ability to protect themselves from SARS-CoV-2 infection

Log likelihood = − 305.41; χ² = 74.67 (9 df); p < 0.0001

Not reporting at least one common symptom compatible with COVID-19 in the previous 3 months

0.45

0.01

0.3–0.69

 < 0.001

Institution

Prison 1

1.79

0.38

1.18–2.73

0.006

Prison 2

1^a

Working activity inside the prison

2.31

0.5

1.51–3.54

 < 0.001

No generalized anxiety symptoms

0.61

0.13

0.4–0.92

0.019

No need of additional information about COVID-19

0.46

0.1

0.3–0.71

 < 0.001

Foreigners

0.57

0.23

0.26–1.26

0.163

Not believing that COVID-19 will cause serious consequences in their prison

0.65

0.17

0.39–1.09

0.103

Poor knowledge about effective infection control measures for COVID-19

0.78

0.2

0.46–1.3

0.339

Having received information about COVID-19 from physicians

1.47

0.38

1.18–2.73

0.132

Model 3. Willingness to receive COVID-19 vaccination

Log likelihood = − 343.85; χ² = 126.81 (10 df); p < 0.0001

Older

1.04

0.009

1.02–1.06

 < 0.001

Institution

Prison 1

1^a

Prison 2

2.71

0.62

1.73–4.25

 < 0.001

Prison 3

4.46

1.07

2.78–7.14

 < 0.001

Knowing that a COVID-19 vaccination is available

2.61

0.6

1.67–4.1

 < 0.001

Believing that COVID-19 is more serious than influenza

2.21

0.84

1.05–4.66

0.037

Self-confidence about the ability to protect themselves from SARS-CoV-2 infection

1.65

0.4

1.03–2.64

0.038

High school or university degree

1.34

0.29

0.87–2.06

0.176

Being affected by chronic diseases

1.24

0.28

0.79–1.94

0.341

Not believing that COVID-19 will continue to spread in Italy

0.82

0.16

0.55–1.21

0.321

Having received information about COVID-19 from family and friends

1.34

0.27

0.9–2.01

0.150