Update on the reasoning why the FDA has started the EAU process for 2-5 year olds. Once again, the answer is a matter of degrees, not the binary "yes or no" thinking that it seems many people have trouble moving beyond.
At the dose that Pfizer chose to investigate, the antibody response was lower than hoped for in this age group after two injections. However, at least in adults, the equivalent antibody concentration does confer a decent amount of protection against severe illness, just not to the degree that they would like to start out. So, the thought process goes something like "This is good enough, and it looks like the preliminary data coming in suggests the third dose will boost the antibody level to the original target, so let's get the ball rolling now." I'll need to actually confirm this all when the FDA publishes the EUA paper, but at least that sounds good enough for my 3 year old.
In other news, the makers of Novovax have finally submitted their EUA request to the FDA. This vaccine's niche might be that because it contains a mixture of proteins, it might offer better protection across multiple strains. I suspect it might find a role as a general booster. The downsides of a protein-based vaccine vs. the mRNA versions are that it will almost certainly trigger more allergic reactions, and the manufacturing process isn't nearly as easy to quickly scale-up.