The University of Michigan offers a Master of Science in Population and Health Sciences via Coursera. The program is quite expensive... Program: 42 credits Resident: $960/credit Non-Resident: $1060/hour URL: https://www.coursera.org/degrees/master-of-population-science-umich
Michigan is a constant top ten school in Public Health (ranked slightly above my Univ of Minnesota) per US News. That price is close to their regular tuition rates for a MPH or MS on-campus degree program.