Vu M. Ngo, Klaus F. Zimmermann, Phuc V. Nguyen, Toan Luu Duc Huynh and Huan H. Nguyen (2022). “How education and GDP drive the COVID-19 vaccination campaign”, OPEN ACCESS: Archives of Public Health 80 (171) 2022. DOI 10.1186/s13690-022-00924-0.