Coverage of primary and booster vaccination against COVID-19 by socioeconomic level: A nationwide cross-sectional registry study

Abstract

High and equitable COVID-19 vaccination coverage is important for pandemic control and prevention of health inequity. However, little is known about socioeconomic correlates of booster vaccination coverage. In this cross-sectional study of all Norwegian adults in the national vaccination program (N = 4,190,655), we use individual-level registry data to examine coverage by levels of household income and education of primary (≥2 doses) and booster (≥3 doses) vaccination against COVID-19. We stratify the analyses by age groups with different booster recommendations and report relative risk ratios (RR) for vaccination by 25 August 2022. In the 18-44 years group, individuals with highest vs. lowest education had 94% vs. 79% primary coverage (adjusted RR (adjRR) 1.15, 95%CI 1.14-1.15) and 67% vs. 38% booster coverage (adjRR 1.55, 95% CI 1.55-1.56), while individuals with highest vs. lowest income had 94% vs. 81% primary coverage (adjRR 1.10, 95%CI 1.10-1.10) and 60% vs. 43% booster coverage (adjRR 1.23, 95%CI 1.22-1.24). In the ≥45 years group, individuals with highest vs. lowest education had 96% vs. 92% primary coverage (adjRR 1.02, 95%CI 1.02-1.02) and 88% vs. 80% booster coverage (adjRR 1.09, 95%CI 1.09-1.09), while individuals with highest vs. lowest income had 98% vs. 82% primary coverage (adjRR 1.16, 95%CI 1.16-1.16) and 92% vs. 64% booster coverage (adjRR 1.33, 95%CI 1.33-1.34). In conclusion, we document large socioeconomic inequalities in COVID-19 vaccination coverage, especially for booster vaccination, even though all vaccination was free-of-charge. The results highlight the need to tailor information and to target underserved groups for booster vaccination.

Factors underlying COVID-19 booster vaccine uptake among adults in Belgium

“…Bennett et al and Della Polla et al reported on the possible effect of previous COVID-19 infection on first and second booster intention respectively, based on self-reported surveys with limited study samples, but the results were not significant [9,10]. A study by Hansen et al showed a significant negative effect of COVID-19 infection on first booster uptake [11], which is in line with our study results.…”

“…Studies investigating booster willingness showed as well conflicting results concerning sex [5][6][7]. Regional differences in booster uptake could possibly be explained partially by socioeconomic factors and migration background which can influence vaccine hesitancy [2,8,9,11,12]. The Belgian regional effect was also demonstrated by a previous study concerning PC uptake in Belgium [13].…”

“…Our database does not contain any perception data, hence we cannot link observational data with opinionated data. Thirdly, our model included basic demographic factors and infection history as predictors, but other individual-level factors can influence booster uptake as well, as shown in other studies [11][12][13][14]16]. Variables such as household income, migration background, level of social deprivation, profession (healthcare or non-healthcare) and underlying illnesses, will be considered in future analyses to provide a more comprehensive understanding of booster uptake.…”

“…We identified only few articles that described registry-based studies examining the association between socio-demographic and economic factors, and COVID-19 (booster) vaccination. These studies showed a higher vaccine uptake among older individuals, females and those without prior COVID-19 infection while lower uptake was observed among socially deprived individuals and those with a migrant background [11][12][13][14][15][16]. Even though several studies looked into previous COVID-19 infection, none of the aforementioned studies have examined the potential impact of both frequency and timing of individual COVID-19 infections on booster uptake, specifically [3,6,[9][10][11]16].…”