I got into 4 international health programs (BU, JH, Emory, and Columbia). I studied abroad for 7 months and while it wasn't health related, its what made me decide to go into PH and I wrote about that in my essays. I also speak 2 languages other than English and have 1 yr domestic work in public health with non-English speaking populations.
If you don't technically have the work experience, just explain how your other work or study experiences have given you skills that can contribute to global health. If you have exp. working with different populations or cultures that would probably be good too.