Again sorry for the late replies;
I am currently looking into the storage and transportation of vaccines, I have talked to 2 nurses so far, one says she picks up her vaccines from a pharmacy or similar on the day, for the day, where as the other will often have vaccines for several days and would therefore keep them in the fridge.
Do you have to keep vaccines for a long period of time?
One of my ideas is to have a built in refrigerated module, possibly one that you could take out and then put in your fridge when your at home, this would have a power source that would have to be recharged (probably daily).
Another idea would be to have a special insulated module to keep the required temperature, this may have slots to put the ice/gel packs around the vaccines, but not touching them in case it causes accidental freezing.
Do you think these would be useful? or would the fact that you already have a vaccine transport bag mean you keep using that? and therefore maybe just an available slot to put them in?
Although I am aiming to design a trolley, I am also looking into the possibility of it being more of an over-the-shoulder bag, or at least having it as an option. Forgetting the problems that you have had with trolleys and over the shoulder bags in the past, would you prefer a trolley or bag, if they did more-or-less the same thing?