IJPDS International Journal of Population Data Science IJPDS 2399-4908 Swansea University 10.23889/ijpds.v9i5.2736 9:5:247 Conclusions and Implications Aldridge Sarah J 1 Agrawal Utkarsh 2 Murphy Siobhán 3 Millington Tristan 4 Akbari Ashley 1 Almaghrabi Fatima 4 Anand Sneha N 2 Bedston Stuart 1 Goudie Rosalind 2 Griffiths Rowena 1 Joy Mark 2 Lowthian Emily 5 de Lusignan Simon 2 Patterson Lynsey 6 7 Robertson Chris 8 9 Rudan Igor 10 Bradley Declan T 3 7 Lyons Ronan 1 Sheikh Aziz 4 Owen Rhiannon K 1 Population Data Science, Swansea University Medical School, Faculty of Medicine, Health, and Life Science, Swansea University Nuffield Department of Primary Care Health Sciences, University of Oxford Centre for Public Health, Queen’s University Belfast Usher Institute, University of Edinburgh Department of Education and Childhood Studies, School of Social Sciences, Swansea University Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, UK Public Health Agency Department of Mathematics and Statistics, Strathclyde University Public Health Scotland Centre for Global Health, Usher Institute, the University of Edinburgh 18 09 2024 2024 9 5 2736 This work is licenced under a Creative Commons Attribution 4.0 International License. This article is available from the IJPDS website at: https://ijpds.org/article/view/2736 Background and Objectives

SARS-CoV-2 infection in children and young people (CYP) can lead to life threatening conditions including COVID-19, transmission to more vulnerable individuals, or even long COVID. Vaccination against COVID-19 reduces the chance of infection and transmission of the virus, but vaccine uptake in the UK has been shown to decrease with age.

 Approach

We undertook a multistate-model approach to estimate hazard ratios on national cohorts constructed from linked health and administrative data, adjusting for several demographic factors. The models were applied to 3,433,483 CYP aged 5-17 years between 4th August 2021 and 31st May 2022. The results were combined in a random effects meta-analysis.

 Results

Uptake of the first COVID-19 vaccine in CYP was lower compared to older age groups in the UK, and diminished further with subsequent doses (34%, 20% and 2% for 1st, 2nd, and booster dose respectively). Age of the CYP and vaccination status of the adults in the household were identified as important risk factors. For example, 5-11-year-olds were less likely to receive their first vaccine compared to 16-17-year-olds (adjusted Hazard Ratio [aHR]: 0.10 (95%CI: 0.06-0.19), and CYP in unvaccinated households were less likely to receive their first vaccine compared to partially vaccinated households (aHR: 0.19, 95%CI 0.13-0.29).

 Conclusions and Implications

Our work highlights the need for targeted strategies to increase COVID-19 vaccine acceptance and uptake among CYP, especially considering the influence of parental consent and household factors. Further research could help identify risk factors in household types to investigate more direct associations, which may be influenced by factors such as living with vulnerable people, familial structure, or deprivation.