Researchers have gained new understanding of the virus that causes hepatitis B and the ‘spiky ball’ that encloses its genetic blueprint. They looked at how the capsid — a protein shell that protects the blueprint and also drives the delivery of it to infect a host cell — assembles itself. The capsid is an important target in developing drugs to treat hepatitis B, a life-threatening and incurable infection that afflicts more than 250 million people worldwide.