We've been down this path before with vaccines. Often what seems promising early on doesn't pan out long-term.
This is why clinical trials are so lengthy. You have to operate at the time-constants of biology and the human body rather than political or business time-constants. The former are far longer than the latter.
BTW if you get a COVID vaccine right now, you are literally a clinical trial subject/participant. COVID vaccine clinical trials do not end until 2023 in the US based on FDA documents.
Clinical trials for vaccines take a while because we don't intentionally infect people and it takes a long time for the test population to naturally catch whatever it is.
They went fast for COVID because it's a pandemic and everyone was getting it.
This is why clinical trials are so lengthy. You have to operate at the time-constants of biology and the human body rather than political or business time-constants. The former are far longer than the latter.
BTW if you get a COVID vaccine right now, you are literally a clinical trial subject/participant. COVID vaccine clinical trials do not end until 2023 in the US based on FDA documents.