Just which vaccine are we talkign about exactly? There are many projects currently done in many countries. According to a tracker I sometimes chck there are over 160 projects in a pre-clinical phase, 24 in phase I (i.e. general safety in a small group of healthy subjects), 19 in phase II (focus on dosage with several hundred subjects), 11 in phase III (test of efficacy in several thousands of subjects over a longer period of time) and 2 have already been admitted. The one that has been making international headlines these days as the best one so far and a possible gamechanger for the entire planet was developed by the German company BioNTech, a relatively small nerdy research company founded by two idealistic professors of medicine that has spent the last 12 years or so researching the use of mRNA treatment to combat cancer, based on the Nobel Prize winning research of of Fire and Mello. They are playing the long game, investing years and years of research into a possible new generation of cancer treatment that would revolutionize oncology, not out for a quick buck. With this pandemic they applied their expertise to the development of a Covid vaccine based on that new technology, but the are not the only ones banking on that approach. Of the many projects currently being run some are based on traditional vaccine methods and some work based on this relatively new mRNA approach. This one was tested it on about 44.000 subjects and it has shown to be both safe and effective. There is another German biotech company, CureVac, which is using a similar approach, the one Trump unsuccessfully tried to buy out under the condition that Americans would get the vaccine before the rest of the planet, which announced that they too will be ready in a few weeks. Several others will likely follow. They are all complying to medical test procedures.
It has nothing to do with China or the Republican party and it most definitely isn't a "rushed cocktail of vitamins and chemicals". It is part of a completely new generation of impressive hightech vaccines.
The 2006 Nobel Prize in Physiology or Medicine - Advanced information - NobelPrize.org
COVID-19 | BioNTech
RNA vaccine - Wikipedia