Though often overlooked in lists of activities pertaining to global health, European collaborations with UCSF researchers are very common. Large clinical trials studying medications for diseases such as heart disease, cancer, or HIV often include European cohorts in their studies. UCSF scientists often gain training in Europe and vice versa. UCSF researchers are part of trans-national networks that study topics as diverse as neonatal stroke and HIV and hepatitis C coinfection among injection drug users (IDU).