Keep your expectations in check.It now seems so long ago that Pfizer (PFE +0.50%) became the first company in the biopharmaceutical industry to generate over $100 billion in annual sales. The drugmaker achieved this milestone thanks to its dominance in the coronavirus vaccine market. However, this niche has since shrunk considerably -- and it could become even smaller next year. Regulators in the U.S. are making it harder for healthy individuals to get vaccinated.Pfizer needs a way to replace this dwindling ...