Table 2.
Summary of nodes and relationships between nodes in a Bayesian network for assessing risks versus benefits of the AstraZeneca COVID-19 vaccine.
| Node name (number) | Description | Potential values | Node type | Parent nodes | Child nodes |
|---|---|---|---|---|---|
| AZ vaccine doses (n1) | Version 1: Vaccine dose number Version 2: Vaccine coverage in population |
Version 1: None, 1st dose, 2nd dose Version 2: None, one dose only, two doses |
Input | N/A – Default priors: 30% unvaccinated, 35% had one dose only, 35% had two doses. | n6, n10, n9 |
| Age group (n2) | Age group | 0–9,10–19, 20–29,30–39, 40–49, 50–59, 60–69, 70+ | Input | N/A – Default priors: population distribution of Australia | n6, n7, n8, n11, n18 |
| SARS CoV-2 variant (n3) | Dominant SARS CoV-2 variant(s) currently circulating | Alpha/wild, Delta | Input | N/A – Default priors: 5% Alpha/wild and 95% Delta | n9, n10, n11 |
| Intensity of community transmission - x% over 6 months (n4) | Probability of infection over 6-months based on different levels of community transmission | None, ATAGI definitions of low, med, high, 1%, 2%, NSW 200 cases/day, NSW 1000 cases/day, Vic 1000 cases/day, QLD 1000 cases/day |
Input | N/A – Defaults to uniform distribution | n14 |
| Sex (n5) | Sex | Male, female | Input | N/A – Defaults to uniform distribution | n12, n13, n18 |
| Vaccine-associated TTS (n6) | Probability of AZ vaccine-associated TTS | Yes, no | Intermediate | AZ vaccine doses (n1), Age group (n2) | n15 |
| CVST over 6 weeks (n7) | Probability of developing CVST over 6 weeks | Yes, no | Intermediate | Age group (n2) | n16 |
| PVT over 6 weeks (n8) | Probability of developing PVT over 6 weeks | Yes, no | Intermediate | Age group (n2) | n17 |
| Vaccine effectiveness against symptomatic infection (n9) | Effectiveness of the vaccine at preventing symptomatic SARS CoV-2 infection | Yes, no | Intermediate | AZ vaccine doses (n1), SARS CoV-2 variant (n3) | n14 |
| Vaccine effectiveness against death (n10) | Effectiveness of the vaccine at preventing deaths from symptomatic SARS CoV-2 infection | Yes, no | Intermediate | AZ vaccine doses (n1), SARS CoV-2 variant (n3) | n18 |
| Relative risk of infection depending on age and variant (n11) | Relative risk of COVID-19 infection depending on age and variant | Yes, no | Intermediate | Age group (n2), SARS CoV-2 variant (n3) | n14 |
| CVST from Covid infection (n12) | Probability of developing CVST if develops symptomatic COVID-19 | Yes, no | Intermediate | Sex (n5), Risk of symptomatic infection under current transmission and vaccination status (n12) | n20 |
| PVT from Covid infection (n13) | Probability of developing PVT if develops symptomatic COVID-19 | Yes, no | Intermediate | Sex (n5), Risk of symptomatic infection under current transmission and vaccination status (n12) | N/A |
| Risk of symptomatic infection under current transmission and vaccination status (n14) | Probability of symptomatic COVID-19 | Yes, no | Intermediate | Intensity of community transmission - x% over 6 months (n4), Vaccine effectiveness against symptomatic infection (n9), Relative risk of infection depending on age and variant (n11) | n19 |
| Die from vaccine-associated TTS (n15) | Proportion of the population that will die from vaccine-associated TTS | Yes, no | Outcome | Vaccine-associated TTS (n6) | N/A |
| Die from CVST (n16) | Probability of dying from CVST (background rate in those who have not had vaccine or infection) | Yes, no | Outcome | CVST over 6 weeks (n7) | N/A |
| Die from PVT (n17) | Probability of dying from PVT (background rate in those who have not had vaccine or infection) | Yes, no | Outcome | PVT over 6 weeks (n8) | N/A |
| Die from Covid (n18) | Probability of dying from COVID-19 | Yes, no | Outcome | Age (n2), Sex (n5), Vaccine effectiveness against death (n10), Risk of symptomatic infection under current transmission and vaccination status (n12) | N/A |
| Die from Covid-related CVST (n19) | Probability of dying from COVID-19 related CVST | Yes, no | Outcome | CVST from SARS COV-2 infection (n13) | N/A |
| Die from Covid-related PVT (n20) | Probability of dying from COVID-19 related PVT | Yes, no | Outcome | PVT from SARS COV-2 infection (n14) | N/A |