Infectious diseases and related complications, such as pneumonia and sepsis, are the world’s number one cause of morbidity and mortality among children younger than five years of age. More than 3 million deaths result from such diseases and complications each year, with drug resistance a major exacerbating factor. Globally, more than 214 000 infants (under one year of age) die because of antimicrobial resistance annually, with up to 40% of all bacterial infections among babies showing drug resistance. Neonates (up to four weeks old) and infants are especially vulnerable because their immune systems are not fully developed, their behaviours naturally expose them to more and different microbes than adults, and children living in poverty are especially susceptible to drug-resistant bacteria because of water, sanitation and hygiene problems. Few paediatric-focused formulations are under development today.