Public health is a great field to be in! Right out of college, you may want to consider entry-level research or data analyst positions at various companies. I do not have experience in the field myself, but I do have a friend who got a entry-level data analyst position in the National Institutes of Health (NIH). Here is another article that may address your question more directly - https://www.linkedin.com/pulse/20140731114012-1181952-how-to-seek-out-a-public-health-career-without-experience/. There are usually plenty of great jobs available for those with bachelors + work experience in a field, but a masters (or graduate degree) will definitely help you advance professionally. I have found that is often helpful to "stalk" people on LinkedIn that have positions you would like to hold to see what types of experience and education they have!