Overview
Title I of HIPAA — the Health Insurance Portability and Accountability Act of 1996 (Pub. L. 104-191) — protects people's access to health insurance when they change or lose a job. It doesn't cover patient privacy — that's Title II — instead, Title I focuses on making sure health coverage moves with you and isn't taken away or watered down because you've been sick.
Most Title I protections took effect for group health plan years beginning on or after July 1, 1997, under interim final rules published April 8, 1997 (62 FR 16893).
Note on the Affordable Care Act (2010)
The ACA later expanded on several Title I protections — most notably, it eliminated preexisting condition exclusions entirely for most plans (see the note below). Title I's rules still form the legal foundation, but some have been superseded in practice.