I want to go into a different find of Nursing, I enjoy Nursing but especially infectious disease. How would I get certified in I&D

You don’t need to be certified in ID to work in an ID clinic. Experience helps. Public Health Departments in larger cities have TB clinics, Sexual health clinics, and immigration clinics that can be good places to gain ID experience.

You could take the CIC exam which would make you certified in Infection control (CIC- certified in Infection Control)
I have been a nurse for 40 years and have been in the IP role for 3 years, it's all new daily learning experience for me. IP is definitely a position that is becoming much more in demand. Good Luck.

To get certified, you need to take the certification test through APIC.