vaccines

In this discussion board (DB), please post your original thread include the following in your discussion:

Find at least 2 credible resources for vaccine development. The resource can be a video, government website, documentary, etc. Write the resources in APA format at the bottom of your original post. The vaccine does not have to be against COVID-19.  For example, you can research Polio, MMR, Hep B vaccine among many others that have already been developed and tested.
Summarize the information you gathered.
Questions you may want to answer in your summary: What was the vaccine for? What was the timeline from development to general use for the public? What precautions should be taken?
These posts need to be a couple of paragraphs and should not exceed a page (minimum of 250 words required for full credit of original post).  Your original, first post must include the resource in APA format and is due by Friday, (PST, 11:59 pm).