That's incorrect. You must have misunderstood.
A biologics license (aka "full approval") of a vaccine requires 6 months of safety data following the final dose in the series in a phase 3 clinical trial.. An EUA requires 2 months. During the panel meeting they were debating whether to issue an EUA or wait for a biologics license application, which could have happened as early as.... February.
What they are doing now with the continued trials is primarily to understand how the immune response holds up over time. Yes, they continue to follow up on safety data, but they do this for all vaccines after
approval as well as before.
As the American Academy of Pediatrics said
, vaccines do not have long term effects that manifest themselves more than about 6 weeks after your shot. That's been the case for every vaccine in the modern era.
The reason that most vaccine trials take so long isn't the phase 3 trial, it's because most vaccine candidates don't work. We got lucky with COVID in that it has an easy target (the spike protein) and we had a new tech 30 years in the making (and testing) ready to go.
Vaccines are among the safest medications you can take. This one is out of your system in ~36 to ~48 hours. All it does is show something to the immune system so the immune system can recognize it in the future.