Medical Ethics

What is public health, and how is it different from other kinds of medical practices?  What are some examples of public health policies?  In the era of COVID-19, what are some of the moral issues raised by governmental involvement in collective and individual health?  In other words, ought the government, in the form of the CDC, for example, have the right to dictate and/or enforce both personal and group behaviors for the public good?  Why or why not?