Did you know that you can use MOOC (Massive Open Online Courses) to further your education or to learn more about areas of interest?
A list of the courses available can be found at https://www.coursera.org. You can take a course for free or enroll and pay a nominal fee for a certificate. Most courses can be completed in four to six weeks at your own pace, and you can enroll at any time. Two examples of public health courses are psychological first aid (https://www.coursera.org/learn/psychological-first-aid) and systems thinking in public health (https://www.coursera.org/learn/systems-thinking), both offered by Johns Hopkins University.
Take some time to browse the course offerings and check back periodically as new courses are added regularly.