A complete guide to Pfizer stock A complete guide to Pfizer stock Oliver Brett May 10, 2021 3:42 PM Long before it rolled out the first Covid-19 vaccine, Pfizer had been at the forefront of mass production of medicine across the globe. But what are its strengths and weaknesses going forward? Our guide endeavours to give you the answers. Share: What does Pfizer do? Founded by two German immigrants in New York in the middle of the 19th century, Pfizer has grown from its early roots mass-producing citric acid and penicillin to become one of the biggest names in “big pharma”, developing and produces medicines and vaccines for immunology, oncology, cardiology, endocrinology, and neurology.