In the early days of the COVID-19 pandemic, Moderna (MRNA -1.89%) was a top performer, from both a share-price and an earnings perspective. As one of the leading coronavirus vaccine companies, the biotech brought in billions of dollars in annual earnings and saw its stock price jump more than 2,300% from January 2020 through early August of 2021. But in recent years, its stock performance and earnings have disappointed investors.With demand for COVID vaccination on the decline, Moderna hasn't been able to c ...