Yesterday a reporter in Israel has counted its antibodies in a laboratory. Afterwards she interviewed a scientist and he has translated the numbers. She had just 15 defenses in a certain amount of her blood after 5 months. If you had 1000, she would be very well protected. 15 defenses is almost no protection. She got a refresher immediately. As a rule of fist, the younger one is, the longer the vaccination protection holds.
You do not know that yet. For the age group under 60, no refresh vaccine will be necessary this year. At the age group over 60, this could look different. But you have to wait, still the data is too thin to conclusions ziato be able to do.
In addition, it must be remembered that many people in developing countries (esp. Africa) do not even receive an emission. This will take precedence over a refresh vaccination for older ones.
In the risk groups you will probably make it this autumn and see what happens
That is not fixed yet. I had already asked for my second vaccination, but the Robert Koch Institut has not decided yet.