Global socioeconomic inequalities in vaccination coverage, supply, and confidence

Categories: Disease & Virus

May 9, 2025

Vaccination coverage analysis

Globally, coverage for four vaccines showed a slight upward trend from 2015 to 2019 (DTP1: from 89% to 90%; DTP3 and POL3: from 85% to 86%; MCV1: from 84% to 86%) (Fig. 1 and Supplementary Fig. 1). However, coverage declined between 2019 and 2021, reaching its lowest point since 2015 in 2021 (DTP1: from 90% to 86%; DTP3, MCV1, and POL3: from 86% to 81%). In 2022, coverage increased for all four vaccines (DTP1: from 86% to 89%; DTP3 and POL3: from 81% to 84%; MCV1: from 81% to 83%). In 2023, the coverage of DTP1, DTP3, and MCV1 remained unchanged from 2022, while POL3 coverage showed a slight decline (from 84% to 83%). For the economic-related inequality analysis, data from 189 (96.9% of the 194 WHO Member States) countries/territories were included, while for the education-related inequality analysis, data from 191 (98.5%) countries/territories were used. Global economic- and education-related between-country inequalities in vaccination coverage were observed, with a statistically significant (alpha = 0.05) positive concentration index (all p < 0.001). From 2015 to 2019, the economic-related inequalities between countries for the coverage of four vaccines decreased, with the largest reduction observed in DTP3 (Fig. 1 and Supplementary Table 1). Over the same period, education-related between-country inequalities declined for DTP3 and POL3 coverage, remained stable for DTP1 coverage, and fluctuated for MCV1 coverage. However, these inequalities across all four vaccines increased in 2020, peaked in 2021, and then declined in 2022. The economic-related inequalities further decreased in 2023 relative to 2022.

**Fig. 1: Global economic- and education-related between-country inequalities in vaccination coverage.**

The African Region (AFR) had the lowest vaccination coverage, with over 30% of countries/territories reporting coverage below 75% for DTP3, MCV1, and POL3 (n = 47, Supplementary Fig. 2). In the Region of the Americas (AMR), there was a declining trend in vaccination coverage, with Haiti and Venezuela having notably lower DTP3 and POL3 coverage compared to other countries/territories (n = 35, Supplementary Fig. 3). 82% and 92% of countries/territories reported coverage for the four vaccines over 75% in the South-East Asia Region (SEAR) (n = 11) and European Region (EUR) respectively (n = 53) (Supplementary Figs. 4, 5). Somalia in the Eastern Mediterranean Region (EMR) and Papua New Guinea in the Western Pacific Region (WPR) exhibited notably lower vaccination coverage compared to other countries/territories in their respective region (Supplementary Figs. 6, 7). From 2015 to 2019, economic- and education-related inequalities between WHO regions gradually declined (Supplementary Table 2). However, inequalities increased in 2020 and 2021 before decreasing again in 2022. In 2023, a slight increase in economic-related inequalities in DTP3, MCV1, and POL3 coverage was observed compared to 2022.

EMR exhibited the highest levels of economic- and education-related inequalities, followed by the WPR, while the EUR demonstrated the lowest levels of inequalities (Fig. 2). Economic- and education-related between-country inequalities in six WHO regions did not show a similar trend between 2015 and 2023. Before 2020, economic-related inequalities in coverage of four vaccines exhibited a decreasing trend in the EUR, SEAR, EMR, and WPR, while showing an increasing trend in the AMR. The economic-related inequalities in coverage of DTP3 and POL3 exhibited an increasing trend in the AFR. In 2020, compared to 2019, economic-related inequalities increased in six WHO regions. In 2021, economic-related inequalities decreased in the EUR compared to 2020, but increased in other WHO regions. By 2022, economic-related inequalities had decreased compared to 2021 in AFR, SEAR, and WPR, but continued to rise significantly in the AMR and EMR. The economic-related inequalities in DTP1 and DTP3 coverage had increased in the AMR in 2023 than 2022. The education-related inequalities in coverage of four vaccines increased in the AMR and EMR since 2020. Between-country inequalities were statistically significant (p < 0.001) in the EMR and WPR between 2015 and 2023 (Supplementary Tables 3, 4). Sensitivity analyses revealed that the values and trends of economic-related inequalities at both global and regional levels, calculated using GDP per capita and GDP per capita in PPP, were closely aligned (Supplementary Fig. 8 and Tables 5, 6).

**Fig. 2: Regional economic- and education-related between-country inequalities in vaccination coverage.**

The coverage of four vaccines in LICs was lower than that in high-income-countries (HICs), upper-middle-income countries (UMICs), and lower-middle-income countries (LMICs). The coverage of four vaccines in LICs exhibited a downward trend from 2015 to 2021, followed by an increasing trend from 2021 to 2023 (Supplementary Fig. 9 and Table 7). From 2015 to 2021, inequalities between country-income groups gradually increased (Supplementary Table 8). Since 2022, economic-related inequalities have shown a decline. Economic-related between-country inequalities within country-income groups were not statistically significant (Supplementary Table 9). Statistically significant education-related between-country inequalities in MCV1 (concentration index: 0.032 to 0.051) and POL3 coverage (concentration index: 0.023 to 0.039) were observed in the LMICs between 2015 and 2022 (p < 0.001) (Supplementary Table 10). In 2015 and 2016, the concentration index (below zero) associated with education in DTP1, DTP3, and POL3 coverage was statistically significant (p < 0.001) in the HICs.

Vaccine supply analysis

After excluding “No Response” (NR), “No data” (ND), and missing values (retaining only “Yes” or “No” responses), 195 countries/territories reported DTP-containing vaccine (DTPCV) and MCV stock-out status for at least 1 year between 2015 and 2022, and 185 countries/territories did so for inactivated polio vaccine (IPV) (Supplementary Tables 11, 12). A higher proportion of countries/territories in LICs, LMICs, and UMICs provided DTPCV and MCV stock-outs information compared to HICs. Across all four income groups, the proportion of countries/territories reporting stock-outs status in 2020 was lower than in 2019. Over 2015–2022, 94 countries/territories reported at least one DTPCV stock-out, 76 reported at least one MCV stock-out, and 87 reported at least one IPV stock-out at the national level (Fig. 3). Among them, four countries (Austria, Brazil, Dominica, and Romania) reported DTPCV stock-outs in more than five of the 8 years; two (Dominica and Swaziland) did so for MCV, and two (North Korea and Namibia) for IPV. Additionally, 83 of 154 (providing stock-out information) countries/territories reported at least one stock-out of home-based vaccination records (HBR) for children and/or women between 2015 and 2023, with 12 reporting stock-outs for more than 5 of the 9 years (Supplementary Fig. 10).

**Fig. 3: The reported frequency of national-level vaccine stock-outs from 2015 to 2022.**

Vaccine confidence analysis

A total of 122,146 individuals from 141 countries were included, with the global proportion of individuals with high vaccine confidence standing at 77.00% (Supplementary Table 13). The proportion of individuals with high vaccine confidence was the highest in the SEAR and the lowest in the EUR (Supplementary Fig. 11). Additionally, disparities in proportion of individuals with high vaccine confidence were noted across country-income groups, with the highest proportion observed in LICs and the lowest in the HICs. For the economic-related inequality analysis of vaccine confidence, data from 137 countries were included, while for the education-related inequality analysis, data from 138 countries were used. Globally, the socioeconomic-related between-country inequalities in vaccine confidence were statistically significant (p < 0.001) (Fig. 4). Countries/territories with higher GDP per capita or mean years of schooling were more likely to show lower vaccine confidence. In the LMICs (concentration index: −0.034, 95% confidential interval [95% CI]: −0.066, −0.002, p = 0.039), UMICs (concentration index: −0.064, 95% CI: −0.096, −0.032, p < 0.001), and HICs (concentration index: −0.037, 95% CI: −0.066, −0.008, p = 0.014), education-related between-country inequalities were statistically significant (Supplementary Table 14). In the AFR, economic-related concentration index was −0.030 (95% CI: −0.052, −0.008, p = 0.009).

**Fig. 4: Vaccine confidence by education and income.**

There were 49 countries/territories exhibiting statistically significant education-related within-country concentration indices, with 38 having an index below zero and 11 above zero (Fig. 5 and Supplementary Figs. 12, 13). Income-related within-country inequalities with statistical significance were observed in 41 countries/territories, with index below zero in 28 and above zero in 13. The pro-less-educated and pro-poor within-country inequalities in vaccine confidence (higher vaccine confidence among less-educated/poorer populations) were more likely to be detected in the LICs, LMICs, and UMICs. Within the HICs, nine countries/territories reported pro-well-educated within-country inequalities, while four exhibited pro-less-educated within-country inequalities. There were ten countries/territories reporting pro-rich within-country inequalities in high vaccine confidence within the HICs.