Coronavirus Vaccines - An Introduction by JAMA is a good starting point. https://www.youtube.com/watch?v=KMc3vL_MIeo
COVID-19 Vaccines goes into greater detail. https://www.youtube.com/watch?v=35Idb_lCU4o
https://www.medicalnewstoday.com/articles/covid-19-how-do-in...
"... In an inactivated vaccine, the pathogen is killed or modified in such a way that it is unable to replicate. It cannot cause disease and is, therefore, suitable for those with a compromised immune system.
The inactivation step usually involves heat, radiation, or chemicals to destroy the pathogen’s genetic material, which stops it from replicating.
Inactivated vaccines can trigger a strong immune reaction, but it is usually not as strong as the reaction that live attenuated vaccines can produce. Due to this, a person may need booster shots to ensure ongoing protection.
The COVID-19 vaccines that Sinovac, Sinopharm, and Bharat Biotech have developed are inactivated vaccines. ..."
example the johnson&johnson vaccine [a vector vaccine] is composed of attenuated [part destroyed] human adenovirus [thus non reproductive] that has an insert of conformationaly stabilized spike sequence. this makes ease of shipping and handling, but lacks good efficacy if you are immune to the adenovirus
One is mRNA (?) variant that gets into your cells and makes them produce just the spike protein. This lets your immune system find this protein out and make antibodies.
The other contains instead a partially destroyed viruses which trains the immune system directly on all their parts - the shell, the spikes, etc.
I don't remember which company makes which kind but both are in production.