Vaccination (IMAGE) Swiss Tropical and Public Health Institute Caption An improved understanding of what influences immune system development is key to informing vaccine design for children from low- and middle-income countries. Credit Christian Heuss Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.