Well, he is a doctor do he has knowledge and experience in that area. Are you a virologist?
I am a PhD educated biochemist/molecular biologist with experience in research of infectious organisms and countermeasures development.
Rand Paul is an ophthalmologist (eye doctor). Like most physicians, he is not trained in research theory or practice. I seriously doubt that he is capable of developing a PCR assay, extracting nucleic acid from viruses for analysis, growing virus in the lab, or any other of the hundreds of techniques that I had to learn in the process of earning my PhD. Yet Rand Paul keeps passing himself off as an expert in virology.
As a biochemist/molecular biologist who has never studied eye anatomy and function, I do not and will never claim to have expertise in the area of ophthalmology. The fact that I can legally call myself "Doctor" does not magically give me expertise in fields other than biochemistry and molecular biology.
Be wary of people who present themselves as experts in a subject they never studied. They'll often use their degree to fool people into believing they are experts when their degree has nothing to do with the subject matter.