Covid Q&A: When Do Vaccines Begin to Work?

In this week's edition of the Covid Q&A, we look at how long it takes for vaccines to provide protection.

In hopes of making this very confusing time just a little less so, each week Bloomberg Prognosis is picking one question sent in by readers and putting it to an expert in the field. This week's question comes to us from Paul in the U.K. Paul recently received the Pfizer-BioNTech vaccine. He asks: