MoA—The AstraZeneka vaccine was developed by Oxford University. It will be a no-profit vaccine as its development was financed by public money. The cost per dose will be below $3-4.
Both of the mRNA vaccines developed by Moderna and Pfizer are for-profit vaccines. They seem to be quite good (and no, they do not modify your DNA) but they will cost between $25 and $35 per shot. They also require an elaborate and expensive distribution chain as they can only be stored at very low temperatures. The adenovirus based vaccines can be stored in a normal refrigerator.
The mRNA vaccines hyped in the U.S. media are simply too expensive to be used around the world. If we want to limit the global effects of the SARS-CoV-2 pandemic we will have to use the cheaper vector based vaccines.