I probably read 10-15 medical papers most weeks about Covid and I've read a lot about the gap between doses in the past month. I really hope we don't go down the path, and that we actively discourage people from trying to do this themselves because I've seen a lot of people on social media in recent days trying to push out their appointments.
Yes there is a growing data to show that this may deliver a longer lasting antibody response, but we don't fully understand this. We know in general that longer gaps between vaccines offers a better immune response, and that many (use hepatitis as an example) can be up to 6 months. We do know that T-cell responses may be just as important (or potentially more important) than simply looking at antibodies. At the moment Pfizer still recommend 3 weeks, and the CDC emergency approval has not changed from that - what is going to be interesting is whether final approval sees this timeframe change.
Many countries look the approach of increasing the gap so that they could get more jabs in arms because a single jab offered far more protection than no jab. Delta has now changed that though, and to have good protection two jabs are essential. The sooner we can get both jabs in people's arms, the better.
Any discussion about whether antibodies might be weaker 12 months from now isn't that important in the greater scheme of things because it's pretty clear now that at least a single booster doses is going to be a thing. What is going to be really interesting is how vaccines such as Novavax may work as a booster.