This Series paper examines how mother and baby attributes at the individual level interact with breastfeeding determinants at other levels, how these interactions drive breastfeeding outcomes, and what policies and interventions are necessary to achieve optimal breastfeeding. 

Despite increasing evidence about the value and importance of breastfeeding, less than half of the world's infants and young children (aged 0–36 months) are breastfed as recommended. This Series paper examines the social, political, and economic reasons for this problem.

Guidance documents from 33 countries on newborn care for infants whose mothers are diagnosed with confirmed or suspected COVID-19 were assessed for alignment with WHO recommendations, revealing considerable inconsistencies.

During the COVID-19 pandemic, policy makers and practitioners must learn from mistakes made during the HIV pandemic, when breastfeeding was undermined through isolating infants from their mothers, and formula feeding resulted in more infant deaths than the disease.