My dad also has an MPH, so not only did I get a nice informal medical education, I got a lot of stuff on public health measures as well.
One of his MAJOR mantras- after prevention is cheaper than cures- is that public health policies have saved more lives than medicine ever will. Pharma researchers and MDs may develop a vaccine, but public health officials are the ones who set the policies regarding who gets them and when- especially if they’re deemed crucial enough to mandate inoculations for subgroups or even huge swaths of a population.