Which vaccine is used most widely in newborns worldwide?

The Bacillus Calmette–Guérin, or BCG, vaccine is among the most widely administered vaccines globally, especially in countries with higher tuberculosis burden. It is usually given soon after birth or in early infancy. Although it does not fully prevent all TB infections, it is highly valuable for protecting young children against severe forms such as TB meningitis and disseminated disease. Its broad use has made it a cornerstone of childhood immunization programs for more than a century.