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Table 1 Model parameters, including distributions used in the probabilistic sensitivity analysis

From: The impact of COVID-19 vaccination in prisons in England and Wales: a metapopulation model

Parameter

Mean (SE)

Distribution

Source and notes

R0

5.08 (1.41)

log-normal

[23]

Percentage reduction in R0 due to shielding and cohorting

40%

beta

[17]

Vaccine efficacy against infection – first dose

60% (10–70%)

beta

[24, 25]

Vaccine efficacy against infection – second dose

80% (10–90%)

beta

Vaccine efficacy against disease – first dose

60% (50–90%)

beta

Vaccine efficacy against disease – second dose

85% (50–95%)

beta

Waning of vaccine immunity

Vaccine efficacy falls by 19% (95%CI 8%-34%) over six months

beta

[26]

Duration of natural immunity

16% (95%CI 13–19%) reduction in immunity over one year

beta

[27]

Staff turnover

8.4% per year (0.1%)

beta

[28]. In-migration assumed to be equal to out-migration

New people incarcerated

0.60% per day (0.17%)

beta

[29]. Based on new receptions into local male prisons. In-migration assumed to be equal to out-migration

Number vaccinated per day

20

fixed

Assumption based on insights of author from HMPPS (O’Mara)

Community incidence

0.001 per 10,000 people per day (0.0015)

fixed

[30]

   

[31]

Population size of those incarcerated

820

fixed

[29]. HMPPS Prison Population Tool. Mean for local male prisons

Staff population size – Staff Group 1

70

fixed

[28]. Mean for local male prisons

Staff population size – Staff Group 2

315

fixed

[28]. Mean for local male prisons

Age distribution of people who are incarcerated

 

fixed

[29]. HMPPS Prison Population Data Tool, December 2020. Mean for local male prisons

Age distribution of staff

 

fixed

[32]

Contact patterns—Staff Group 1

80% of contacts with other staff in Group 1; 20% with Staff Group 2

fixed

Internal HMPPS correspondence

Contact patterns—Staff Group 2

20% of contacts with Staff Group 1; 40% with other staff in Group 2; 40% with people who are incarcerated

fixed

Internal HMPPS correspondence

Contact patterns—individuals who are incarcerated

40% of contacts with Staff Group 1; 60% of contacts with other people who are incarcerated

fixed

Internal HMPPS correspondence

Quality-Adjusted Life Year (QALY) loss per symptomatic case

0.008 (4.7 × 10–5)

beta

[33]

QALY loss per non-fatal hospitalisation

0.018 (0.0018)

beta

[34]

QALY loss per non-fatal ICU admission

0.154 (0.0304)

beta

[35]

QALY loss per fatality—staff

Age-dependent (SMR = 2, qCM = 0.9, discount rate = 0.35)

 

[36]

QALY loss per fatality – people who are incarcerated

Age-dependent (SMR = 2.3, qCM = 0.9, discount rate = 0.35)

 

[36, 37]

QALY loss per Adverse Event Following Immunisation (AEFI)—minor

1/365.25

fixed

[20]

Frequency of AEFI—minor

Age-dependent

fixed

[38]

QALY loss per AEFI—fatal

Age-dependent (SMR = 2, qCM = 0.9, discount rate = 0.35)

fixed

[36]

Frequency of AEFI—fatal

0.18 × 3/1000000

fixed

[39, 40]

Lateral Flow Device (LFD) sensitivity

0.8 (0.125)

beta

[41]

LFD uptake among prison staff

0.508 (0.107)

beta

[9]

Vaccine coverage

0.675 (0.148)

beta

[42]