Sorry your friend may have been exposed up to 20 days prior to being vaccinated. Three to four days is more common. she may have been exposes up to a week later. point is vaccine is a preventive and the vaccine needs in excess of 3 weeks to be fully effective. Blame this on the vaccine if you are that un scientific. My money would be on something more in line with actually being exposed to the virus - Nothing to do w the vaccine directly IMHO.

love, joy, peace, patience, kindness, goodness, faithfulness, 23 gentleness, self-control

& Proverbs 21:19