The interesting point is that the CCP didn't even try to do a sub-unit (e.g., S-protein targeting) vax. They certainly could have gone that route if they wanted to.
It is not surprising that the CCP whole virus vaxs are less effective. Coronaviruses are big and complex which can make it harder in general to get a whole virus vax working.
In contrast, sub-unit vaccines are designed to target a specific feature or characteristic of a pathogen -- in SARS2 the spike protein is targeted.
There are tradeoffs with using sub-unit vaxs that the CCP certainly considered. Including that it may be easier for pathogens to mutate to avoid/defeat the narrowly targeted sub-unit vaccines.
Also, there are some plausible theories that using sub-unit vaxs in the middle of a raging pandemic accelerates the mutations and could lead to "blinding" the vaccinated immune systems to the mutated virus. One immunologist suggests we are doing a global 'gain-of-function' experiment.
I don't understand his theory enough to repeat it here, but one comment struck me. He said if you wanted to rapidly evolve/mutate SARS2 into something more dangerous (e.g., gain-of-function), this is exactly how he would do it.
You’re talking about Geert Vanden Bossche? The veterinarian (dogs and cats doctor)? Who posted a nonsensical bunch of fearmongering to LinkedIn and Twitter rather than publishing it in a scientific journal because a science journal would understand it’s laughably stupid nonsense? Yeah, I’m not worried about that. Saw it, laughed at it, all better now.
And coronaviruses are not that “big and complex”. Measles is larger, Influenza is about the same size, as is HIV. Herpesvirus features a genome size that’s 4-8 times larger (125kb to 240kb versus 29.8-29.9kb for SARS-CoV-2). adenovirus 2(Ad2) has a genome size of ~36kb.
Further, the size or complexity of the virus is not terribly relevant to the immunopathology surrounding it.