Exposure notification is a research area focused on using technology, such as mobile applications, to notify individuals when they have been in close proximity to someone who has tested positive for a contagious disease, such as COVID-19. This technology uses Bluetooth signals to track interactions between individuals and can help notify people who may have been exposed to an infectious person so they can take appropriate precautions, such as getting tested or self-isolating. Exposure notification systems aim to help slow the spread of disease by quickly identifying and notifying those who may have been in close contact with an infected individual.