How does Pfizer make its Covid-19 vaccine? We went behind the scenes to see the 60-day process, step by step. https://www.nytimes.com/interactive/2021/health/pfizer-coronavirus-vaccine.html

It begins in a suburb of St. Louis, where vials of DNA containing a coronavirus gene are held in deep freeze.

Bacteria are then modified to take up that DNA, and swirled in a growth medium so they multiply.

Workers here told us they’re proud to be involved with the vaccine. “Every vial that goes to every person goes through us first,” said Sahar Gholami, a lab technician who prepares extracted DNA for shipping to the next facility in the chain.

The next facility will use the DNA as a template to create messenger RNA, the key component of the vaccine. A third facility will finish and package the vaccine.

More than half of the vaccine production timeline is dedicated to testing. “We make hundreds of millions of doses of product going into a lot of people. That’s an awesome responsibility,” said Chaz Calitri, vice president of operations.

See our step-by-step visual explainer for the full process behind the Pfizer-BioNTech vaccine. https://www.nytimes.com/interactive/2021/health/pfizer-coronavirus-vaccine.html