Evaluate how vaccines can be studied in the midst of an epidemic.

Vaccines are intended to protect against an infectious agent (virus or
bacterium). However, emerging viruses challenge vaccine testing claims with
exceptions because of the timing of the epidemic and its unexpected –
unanticipated emergence. Evaluate how vaccines can be studied in the midst of
an epidemic e.g. Ebola

This essay
should demonstrate knowledge of the domain of clinical research: phase 1-3
trials, FDA approval, and the ethical norms of using human subjects in
research, defined in the Common Rule. In
addition, the standard of care for diagnosis and treatment may vary by place,
dependent on resources available. Epidemics and emerging viruses create special
circumstances because they are rarely contained in one geographical site, given
the mobility of people in today’s world.
Document your sources carefully and be sure to cite sources within the
text of the essay. Proof your work and use spell check and grammar check to
help with presentation. Clearly state
beside your name number 1, 2 or 3 as the essay topic you have chosen. Give your
essay a title which should be your thesis statement. Your essay will be 7-10
pages (double spaced, typed, 12 font) and submitted through chalk and wire for
assessment using the rubric included in your syllabus.

I need to explain the idea by two cases as examples.
I need at least 7 resources one of them from the book below.
I am international student, so I need simple words and terms.