I am a certified nurse-midwife (since 2000). I completed my undergraduate nursing education at San Francisco State University (BSN, 1988). I graduated from Emory University in 1999 with an MSN/MPH.
I was generally accepting of, and ignorant about, vaccines until ~2010 when my (now previous) employer began mandating flu vaccine as a condition of employment. It was at that point that I began doing more research. The more I have learned, the more concerned I have become.
While there is data to support efficacy (of varying degrees) of (some) vaccines, there is also plenty of reason to be concerned about undesired secondary effects as well - either from the antigen itself, or from other ingredients in the vaccine (ie: preservatives, adjuvants, or contaminates).
There is also abundant conflict of interest among many who make policy and/or conduct research regarding vaccination, and this decreases confidence that their decisions about policy or their conclusions about data are driven primarily by data, and not another (hidden)
agenda. The lack of transparency and refusal to consider other points of view (ie: that vaccines are not as effective, nor as safe as they have been assumed to be) further erodes trust.
For this reason their use should be voluntary, not mandatory - for either adults or children. There should be a much higher degree of freedom regarding vaccines.