| [1] | Dalton M, Sanderson B, Robinson LJ, Homer CSE, Pomat W, Danchin M, et al. Impact of COVID-19 on routine childhood immunisations in low- and middle-income countries: a scoping review. PLoS Global Public Health 2023;3(8):e0002268. https://doi.org/10.1371/journal.pgph.0002268. |
| [2] | Shet A, Carr K, Danovaro-Holliday MC, Sodha SV, Prosperi C, Wunderlich J, et al. Impact of the SARS-CoV-2 pandemic on routine immunisation services: evidence of disruption and recovery from 170 countries and territories. Lancet Global Health 2022;10(2):e186 − 94. https://doi.org/10.1016/S2214-109X(21)00512-X. |
| [3] | O’Brien KL, Lemango E. The big catch-up in immunisation coverage after the COVID-19 pandemic: progress and challenges to achieving equitable recovery. Lancet 2023;402(10401):510 − 2. https://doi.org/10.1016/s0140-6736(23)01468-x. |
| [4] | Hausdorff WP, Madhi SA, Kang G, Kaboré L, Tufet Bayona M, Giersing BK. Facilitating the development of urgently required combination vaccines. Lancet Global Health 2024;12(6):e1059 − 67. https://doi.org/10.1016/S2214-109X(24)00092-5. |
| [5] | Romero M, Góngora DS, Caicedo ML, Benchabane D, Lopez JG. Cost-minimization and budget impact analysis of a hexavalent vaccine (Hexaxim®) in the colombian expanded program on immunization. Value Health Reg Issues 2021;26:150 − 9. https://doi.org/10.1016/j.vhri.2021.06.001. |
| [6] | Kurosky SK, Davis KL, Krishnarajah G. Effect of combination vaccines on completion and compliance of childhood vaccinations in the United States. Hum Vaccines Immunother 2017;13(11):2494 − 2502. https://doi.org/10.1080/21645515.2017.1362515. |
| [7] | World Health Organization. Vaccination schedule. 2025. https://immunizationdata.who.int/global?topic=Vaccination-schedule&location. [2026-4-11]. |
| [8] | United Nations International Children’s Emergency Fund. UNICEF data warehouse. 2025. https://data.unicef.org/dv_index/?q=immunization. [2026-4-11]. |
| [9] | World Health Organization. Country groupings. 2026. https://www.who.int/observatories/global-observatory-on-health-research-and-development/classifications-and-standards/country-groupings. [2026-4-11]. |
| [10] | The World Bank. World bank country and lending groups. 2025. https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups. [2026-04-11]. |
| [11] | World Health Organization. Progress and challenges with achieving universal immunization coverage. 2025. https://www.who.int/publications/m/item/progress-and-challenges. [2026-4-11]. |
| [12] | GBD 2023 Vaccine Coverage Collaborators. Global, regional, and national trends in routine childhood vaccination coverage from 1980 to 2023 with forecasts to 2030: a systematic analysis for the Global Burden of Disease Study 2023. Lancet 2025;406(10500):235 − 60. https://doi.org/10.1016/s0140-6736(25)01037-2. |
| [13] | World Health Organization. Immunization agenda 2030: a global strategy to leave no one behind. 2020. https://www.who.int/teams/immunization-vaccines-and-biologicals/strategies/ia2030. [2026-4-11]. |
| [14] | Duan YQ, Shi JY, Wang ZB, Zhou SD, Jin YZ, Zheng ZJ. Disparities in COVID-19 vaccination among low-, middle-, and high-income countries: the mediating role of vaccination policy. Vaccines (Basel) 2021;9(8):905. https://doi.org/10.3390/vaccines9080905. |
| [15] | Kallenberg J, Mok W, Newman R, Nguyen A, Ryckman T, Saxenian H, et al. Gavi’s transition policy: moving from development assistance to domestic financing of immunization programs. Health Aff 2016;35(2):250 − 8. https://doi.org/10.1377/hlthaff.2015.1079. |
| [16] | World Health Organization. The big catch-up: an essential immunization recovery plan for 2023 and beyond. 2023. https://www.who.int/publications/i/item/9789240075511. [2026-4-11]. |