The fun of exposing the medical professionals/bureaucracy for what they are.
Mabye @biobook can answer this: How in the world do they know the efficacy of the vaccine? Why would one need 2 doses when antibodies are high after 1 dose?
The literature that publishes clinical trial efficacy explains that. You might need background in biology/medicine/statistics to fully understand what you’re reading.
The 2nd dose in general is to boost antibodies, but FWIU it also affects immunity in the longer term. That second part (long term immunity) is more relevant to those who recovered from COVID.
Medical bureaucracy offers guidance based on what is known, and we don’t have all the data yet. What we do know is that there are known concerns with regards to waiting for another dose could be problematic. How those will play out in the longer term with regards to COVID-vaccination is up in the air both regarding immunity data and the trajectory of the pandemic.