Study how the immune system helps to protect us against diseases and pathogens such as viruses, bacteria, and parasites.

Top ranked hospital devoted entirely to respiratory, allergic and immune system diseases. Offers links to assist in research.

This site offers a wealth of information regarding HIV and AIDS. Content ranges from basic health information found under "FAQ" to topical information such as the risk of AIDS to teens and home care options.

Complete medical education project explores the role and uses of vaccines now and in the past. Find information and analysis about vaccination controversies; answers to frequent questions about vaccinations; timelines of diseases,...

In addition to discussing the use of a vegan diet to lower the risk of arthritis, this article also talks about diet as a means of preventing other diseases and disorders.