Even though scientists have developed vaccines for many of the most common diseases in wealthy countries, the world still lacks vaccines for the biggest killers. Malaria, tuberculosis (TB), and HIV together kill more than 5 million people every year.

To create effective vaccines for these diseases, Grand Challenges in Global Health projects are focused on solving three key challenges:

• Identifying the specific types of immune responses that effective vaccines must elicit.
• Identifying effective new antigens for eliciting these immune responses.
• Improving the reliability of the animal tests that are used to evaluate potential vaccines prior to human trials.

Recent advances in scientific understanding of the causes of disease, the biology of the immune system, and genetics offer significant potential for the development of effective vaccines for HIV, TB, malaria, and many other diseases prevalent in the developing world.