Because the company uses mRNA technology—a type of vaccine that uses the genetic code for a key protein in the virus to teach the body to make that protein and learn how to fight it off—editing the vaccine involves a relatively simple change in the code. “The vaccine we are using now has the original spike protein, and the only thing we basically need to do is cut out this part and take the spike protein of the delta variant,” says Özlem Türeci, co-founder and chief medical officer of BioNTech.

The mRNA technology “can serve as what is called a platform technology, which means that if you just make a change of a sequence of the code, the technology is so stable that everything else stays basically the same,” she says. “So in manufacturing, you don’t need to change too many things that you need to discuss with regulators and show that there’s quality control. You can use the original process.”

Making each new version of the vaccine can take only weeks. “If you have the sequence, then we are able in principle to make the vaccine within less than four weeks,” says cofounder and CEO Uğur Şahin, who led the record-breaking 11-month path of the first COVID vaccine from the lab to approval. (Previously, the fastest vaccine ever developed took four years.) “With all the testing which is required, it takes us less than 100 days to really ship the vaccine. It will become shorter with time, because everything is going to be improved and accelerated. That’s really the power of the technology: You can be extremely fast.”