I wound up with Pfizer, but I actually would have preferred to get J&J, due to the more established vaccine tech with less risk of allergic reaction. They work similarly enough (put *NA into your cells, you build the spike protein yourself, and then react to it) that it’s hard for me to believe that much of the apparent difference in effectiveness is real. J&J scored worse, but on a harder test including the newer strains. So I imagine J&J is comparable to the first shot of Pfizer/Moderna, and although the second shot does make a real difference, the obvious solution is to just get a second shot of J&J. Ideally you would wait until supply caught up with or exceeded demand, and ideally the places administering it would stop caring at that point whether you already had a shot but might charge you for it. In the (likely) worst case where they don’t allow it if you already had a shot, you could lie.
I wound up with Pfizer, but I actually would have preferred to get J&J, due to the more established vaccine tech with less risk of allergic reaction. They work similarly enough (put *NA into your cells, you build the spike protein yourself, and then react to it) that it’s hard for me to believe that much of the apparent difference in effectiveness is real. J&J scored worse, but on a harder test including the newer strains. So I imagine J&J is comparable to the first shot of Pfizer/Moderna, and although the second shot does make a real difference, the obvious solution is to just get a second shot of J&J. Ideally you would wait until supply caught up with or exceeded demand, and ideally the places administering it would stop caring at that point whether you already had a shot but might charge you for it. In the (likely) worst case where they don’t allow it if you already had a shot, you could lie.