Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose

Kirsty Morrison; Lucy Cullen; Allan B. James; Vera Chua; Christopher Sullivan; Chris Robertson; Jade Carruthers; Rachael Wood; Karen Jeffrey; Calum MacDonald; Syed Ahmar Shah; Igor Rudan; Colin R. Simpson; Colin McCowan; Srinivasa Vittal Katikireddi; Zoe Grange; Lewis Ritchie; Aziz Sheikh

doi:10.1016/j.vaccine.2023.07.070

Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose

Kirsty Morrison^* (Corresponding Author), Lucy Cullen, Allan B. James, Vera Chua, Christopher Sullivan, Chris Robertson, Jade Carruthers, Rachael Wood, Karen Jeffrey, Calum MacDonald, Syed Ahmar Shah, Igor Rudan, Colin R. Simpson, Colin McCowan, Srinivasa Vittal Katikireddi, Zoe Grange, Lewis Ritchie, Aziz Sheikh

^*Corresponding author for this work

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Abstract

Background: Vaccination continues to be the key public health measure for preventing severe COVID-19 outcomes. Certain groups may be at higher risk of incomplete vaccine schedule, which may leave them vulnerable to COVID-19 hospitalisation and death. Aim: To identify the sociodemographic and clinical predictors for not receiving a scheduled COVID-19 vaccine after previously receiving one. Methods: We conducted two retrospective cohort studies with ≥3.7 million adults aged ≥18 years in Scotland. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) of not receiving a second, and separately a third dose between December 2020 and May 2022. Independent variables included sociodemographic and clinical factors. Results: Of 3,826,797 people in the study population who received one dose, 3,732,596 (97.5%) received two doses, and 3,263,153 (86.5%) received all doses available during the study period. The most strongly associated predictors for not receiving the second dose were: being aged 18–29 (reference: 50–59 years; aOR:4.26; 95% confidence interval (CI):4.14–4.37); hospitalisation due to a potential vaccine related adverse event of special interest (AESI) (reference: not having a potential AESI, aOR:3.78; 95%CI: 3.29–4.35); and living in the most deprived quintile (reference: least deprived quintile, aOR:3.24; 95%CI: 3.16–3.32). The most strongly associated predictors for not receiving the third dose were: being 18–29 (reference: 50–59 years aOR:4.44; 95%CI: 4.38–4.49), living in the most deprived quintile (reference: least deprived quintile aOR:2.56; 95%CI: 2.53–2.59), and Black, Caribbean, or African ethnicity (reference: White ethnicity aOR:2.38; 95%CI: 2.30–2.46). Pregnancy, previous vaccination with mRNA-1273, smoking history, individual and household severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, and having an unvaccinated adult in the household were also associated with incomplete vaccine schedule. Conclusion: We observed several risk factors that predict incomplete COVID-19 vaccination schedule. Vaccination programmes must take immediate action to ensure maximum uptake, particularly for populations vulnerable to severe COVID-19 outcomes.

Original language	English
Pages (from-to)	5863-5876
Number of pages	14
Journal	Vaccine
Volume	41
Issue number	40
Early online date	7 Sept 2023
DOIs	https://doi.org/10.1016/j.vaccine.2023.07.070
Publication status	Published - 15 Sept 2023

Bibliographical note

Funding Information:
We thank Dave Kelly from Albasoft (Inverness, UK) for his support with making primary care data available, Vicky Hammersley and Natalia Matveyev (University of Edinburgh, Edinburgh, UK) for their support with project management and administration, Graham McGowan and the COVID-19 vaccinate uptake team (Public Health Scotland, Glasgow, UK) for providing vaccination data, and Ruth Dryden, Ross McQueenie, and Heather Williams, (Public Health Scotland, Glasgow, UK) for their help with interpretation of findings. We also thank Rebecca Craig and Jane Oliver (Vaccine Confidence and Equity Team, Public Health Scotland, Glasgow, UK) for leading the clinical risk groups exploratory session on COVID-19 vaccination uptake which helped inform our interpretation. We acknowledge the support of the EAVE II Patient Advisory Group.

Funding Information:
Funding: UK Research and Innovation (Medical Research Council); Research and Innovation Industrial Strategy Challenge Fund; Chief Scientist's Office of the Scottish Government; Health Data Research UK; National Core Studies – Data and Connectivity. SVK acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02), the Scottish Government Chief Scientist Office (SPHSU17) and the Medical Research Council (MC_UU_00022/2).

Data Availability Statement

The data that has been used is confidential.

Keywords

COVID-19 vaccination
Incomplete vaccine schedule
Vaccine hesitancy
Vaccine uptake

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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Cite this

Morrison, K., Cullen, L., James, A. B., Chua, V., Sullivan, C., Robertson, C., Carruthers, J., Wood, R., Jeffrey, K., MacDonald, C., Shah, S. A., Rudan, I., Simpson, C. R., McCowan, C., Vittal Katikireddi, S., Grange, Z., Ritchie, L., & Sheikh, A. (2023). Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose. Vaccine, 41(40), 5863-5876. https://doi.org/10.1016/j.vaccine.2023.07.070

Morrison, K, Cullen, L, James, AB, Chua, V, Sullivan, C, Robertson, C, Carruthers, J, Wood, R, Jeffrey, K, MacDonald, C, Shah, SA, Rudan, I, Simpson, CR, McCowan, C, Vittal Katikireddi, S, Grange, Z, Ritchie, L & Sheikh, A 2023, 'Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose', Vaccine, vol. 41, no. 40, pp. 5863-5876. https://doi.org/10.1016/j.vaccine.2023.07.070

@article{1b8cc92f477f412eb7d877f043840d70,

title = "Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose",

abstract = "Background: Vaccination continues to be the key public health measure for preventing severe COVID-19 outcomes. Certain groups may be at higher risk of incomplete vaccine schedule, which may leave them vulnerable to COVID-19 hospitalisation and death. Aim: To identify the sociodemographic and clinical predictors for not receiving a scheduled COVID-19 vaccine after previously receiving one. Methods: We conducted two retrospective cohort studies with ≥3.7 million adults aged ≥18 years in Scotland. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) of not receiving a second, and separately a third dose between December 2020 and May 2022. Independent variables included sociodemographic and clinical factors. Results: Of 3,826,797 people in the study population who received one dose, 3,732,596 (97.5%) received two doses, and 3,263,153 (86.5%) received all doses available during the study period. The most strongly associated predictors for not receiving the second dose were: being aged 18–29 (reference: 50–59 years; aOR:4.26; 95% confidence interval (CI):4.14–4.37); hospitalisation due to a potential vaccine related adverse event of special interest (AESI) (reference: not having a potential AESI, aOR:3.78; 95%CI: 3.29–4.35); and living in the most deprived quintile (reference: least deprived quintile, aOR:3.24; 95%CI: 3.16–3.32). The most strongly associated predictors for not receiving the third dose were: being 18–29 (reference: 50–59 years aOR:4.44; 95%CI: 4.38–4.49), living in the most deprived quintile (reference: least deprived quintile aOR:2.56; 95%CI: 2.53–2.59), and Black, Caribbean, or African ethnicity (reference: White ethnicity aOR:2.38; 95%CI: 2.30–2.46). Pregnancy, previous vaccination with mRNA-1273, smoking history, individual and household severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, and having an unvaccinated adult in the household were also associated with incomplete vaccine schedule. Conclusion: We observed several risk factors that predict incomplete COVID-19 vaccination schedule. Vaccination programmes must take immediate action to ensure maximum uptake, particularly for populations vulnerable to severe COVID-19 outcomes.",

keywords = "COVID-19 vaccination, Incomplete vaccine schedule, Vaccine hesitancy, Vaccine uptake",

author = "Kirsty Morrison and Lucy Cullen and James, {Allan B.} and Vera Chua and Christopher Sullivan and Chris Robertson and Jade Carruthers and Rachael Wood and Karen Jeffrey and Calum MacDonald and Shah, {Syed Ahmar} and Igor Rudan and Simpson, {Colin R.} and Colin McCowan and {Vittal Katikireddi}, Srinivasa and Zoe Grange and Lewis Ritchie and Aziz Sheikh",

note = "Funding Information: We thank Dave Kelly from Albasoft (Inverness, UK) for his support with making primary care data available, Vicky Hammersley and Natalia Matveyev (University of Edinburgh, Edinburgh, UK) for their support with project management and administration, Graham McGowan and the COVID-19 vaccinate uptake team (Public Health Scotland, Glasgow, UK) for providing vaccination data, and Ruth Dryden, Ross McQueenie, and Heather Williams, (Public Health Scotland, Glasgow, UK) for their help with interpretation of findings. We also thank Rebecca Craig and Jane Oliver (Vaccine Confidence and Equity Team, Public Health Scotland, Glasgow, UK) for leading the clinical risk groups exploratory session on COVID-19 vaccination uptake which helped inform our interpretation. We acknowledge the support of the EAVE II Patient Advisory Group. Funding Information: Funding: UK Research and Innovation (Medical Research Council); Research and Innovation Industrial Strategy Challenge Fund; Chief Scientist's Office of the Scottish Government; Health Data Research UK; National Core Studies – Data and Connectivity. SVK acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02), the Scottish Government Chief Scientist Office (SPHSU17) and the Medical Research Council (MC_UU_00022/2). ",

year = "2023",

month = sep,

day = "15",

doi = "10.1016/j.vaccine.2023.07.070",

language = "English",

volume = "41",

pages = "5863--5876",

journal = "Vaccine",

issn = "0264-410X",

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number = "40",

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TY - JOUR

T1 - Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland

T2 - Two retrospective cohort analyses of the primary schedule and third dose

AU - Morrison, Kirsty

AU - Cullen, Lucy

AU - James, Allan B.

AU - Chua, Vera

AU - Sullivan, Christopher

AU - Robertson, Chris

AU - Carruthers, Jade

AU - Wood, Rachael

AU - Jeffrey, Karen

AU - MacDonald, Calum

AU - Shah, Syed Ahmar

AU - Rudan, Igor

AU - Simpson, Colin R.

AU - McCowan, Colin

AU - Vittal Katikireddi, Srinivasa

AU - Grange, Zoe

AU - Ritchie, Lewis

AU - Sheikh, Aziz

N1 - Funding Information: We thank Dave Kelly from Albasoft (Inverness, UK) for his support with making primary care data available, Vicky Hammersley and Natalia Matveyev (University of Edinburgh, Edinburgh, UK) for their support with project management and administration, Graham McGowan and the COVID-19 vaccinate uptake team (Public Health Scotland, Glasgow, UK) for providing vaccination data, and Ruth Dryden, Ross McQueenie, and Heather Williams, (Public Health Scotland, Glasgow, UK) for their help with interpretation of findings. We also thank Rebecca Craig and Jane Oliver (Vaccine Confidence and Equity Team, Public Health Scotland, Glasgow, UK) for leading the clinical risk groups exploratory session on COVID-19 vaccination uptake which helped inform our interpretation. We acknowledge the support of the EAVE II Patient Advisory Group. Funding Information: Funding: UK Research and Innovation (Medical Research Council); Research and Innovation Industrial Strategy Challenge Fund; Chief Scientist's Office of the Scottish Government; Health Data Research UK; National Core Studies – Data and Connectivity. SVK acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02), the Scottish Government Chief Scientist Office (SPHSU17) and the Medical Research Council (MC_UU_00022/2).

PY - 2023/9/15

Y1 - 2023/9/15

N2 - Background: Vaccination continues to be the key public health measure for preventing severe COVID-19 outcomes. Certain groups may be at higher risk of incomplete vaccine schedule, which may leave them vulnerable to COVID-19 hospitalisation and death. Aim: To identify the sociodemographic and clinical predictors for not receiving a scheduled COVID-19 vaccine after previously receiving one. Methods: We conducted two retrospective cohort studies with ≥3.7 million adults aged ≥18 years in Scotland. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) of not receiving a second, and separately a third dose between December 2020 and May 2022. Independent variables included sociodemographic and clinical factors. Results: Of 3,826,797 people in the study population who received one dose, 3,732,596 (97.5%) received two doses, and 3,263,153 (86.5%) received all doses available during the study period. The most strongly associated predictors for not receiving the second dose were: being aged 18–29 (reference: 50–59 years; aOR:4.26; 95% confidence interval (CI):4.14–4.37); hospitalisation due to a potential vaccine related adverse event of special interest (AESI) (reference: not having a potential AESI, aOR:3.78; 95%CI: 3.29–4.35); and living in the most deprived quintile (reference: least deprived quintile, aOR:3.24; 95%CI: 3.16–3.32). The most strongly associated predictors for not receiving the third dose were: being 18–29 (reference: 50–59 years aOR:4.44; 95%CI: 4.38–4.49), living in the most deprived quintile (reference: least deprived quintile aOR:2.56; 95%CI: 2.53–2.59), and Black, Caribbean, or African ethnicity (reference: White ethnicity aOR:2.38; 95%CI: 2.30–2.46). Pregnancy, previous vaccination with mRNA-1273, smoking history, individual and household severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, and having an unvaccinated adult in the household were also associated with incomplete vaccine schedule. Conclusion: We observed several risk factors that predict incomplete COVID-19 vaccination schedule. Vaccination programmes must take immediate action to ensure maximum uptake, particularly for populations vulnerable to severe COVID-19 outcomes.

AB - Background: Vaccination continues to be the key public health measure for preventing severe COVID-19 outcomes. Certain groups may be at higher risk of incomplete vaccine schedule, which may leave them vulnerable to COVID-19 hospitalisation and death. Aim: To identify the sociodemographic and clinical predictors for not receiving a scheduled COVID-19 vaccine after previously receiving one. Methods: We conducted two retrospective cohort studies with ≥3.7 million adults aged ≥18 years in Scotland. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) of not receiving a second, and separately a third dose between December 2020 and May 2022. Independent variables included sociodemographic and clinical factors. Results: Of 3,826,797 people in the study population who received one dose, 3,732,596 (97.5%) received two doses, and 3,263,153 (86.5%) received all doses available during the study period. The most strongly associated predictors for not receiving the second dose were: being aged 18–29 (reference: 50–59 years; aOR:4.26; 95% confidence interval (CI):4.14–4.37); hospitalisation due to a potential vaccine related adverse event of special interest (AESI) (reference: not having a potential AESI, aOR:3.78; 95%CI: 3.29–4.35); and living in the most deprived quintile (reference: least deprived quintile, aOR:3.24; 95%CI: 3.16–3.32). The most strongly associated predictors for not receiving the third dose were: being 18–29 (reference: 50–59 years aOR:4.44; 95%CI: 4.38–4.49), living in the most deprived quintile (reference: least deprived quintile aOR:2.56; 95%CI: 2.53–2.59), and Black, Caribbean, or African ethnicity (reference: White ethnicity aOR:2.38; 95%CI: 2.30–2.46). Pregnancy, previous vaccination with mRNA-1273, smoking history, individual and household severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, and having an unvaccinated adult in the household were also associated with incomplete vaccine schedule. Conclusion: We observed several risk factors that predict incomplete COVID-19 vaccination schedule. Vaccination programmes must take immediate action to ensure maximum uptake, particularly for populations vulnerable to severe COVID-19 outcomes.

KW - COVID-19 vaccination

KW - Incomplete vaccine schedule

KW - Vaccine hesitancy

KW - Vaccine uptake

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DO - 10.1016/j.vaccine.2023.07.070

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Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose

Abstract

Bibliographical note

Data Availability Statement

Keywords

UN SDGs

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