A German professor came up with a COVID19 antigen vaccine - and is now sued by the government. The article by Spiegel is in German,
The original article (in German)
Here is a recent blog posts in English: ⇚ Please use the link to see translation
QUOTE "With a single 2000-litres reactor, 35 g of antigen can be produced per day, which would suffice for 1 million persons. Using a high-density culturing system, five times as much can be yielded. Within half a year it would be possible to produce enough vaccine for 80% of the population in Germany in a medium-scale laboratory."