Every once in a while, a stock delivers returns to investors that are hard to believe.

Novavax's (NASDAQ:NVAX) performance in 2020 is one such occasion. The vaccine development company has generated life-changing gains for its shareholders, turning even relatively meager sums into fortunes along the way.

A sharply rising chart.

Novavax has made its investors rich. Image source: Getty Images.

Novavax entered 2020 on a low note. It suffered brutal losses in 2019, following disappointing results for its respiratory syncytial virus (RSV) vaccine candidate ResVax in a phase 3 study. Novavax's stock ended the year down a horrific 89%. 

However, Novavax would go on to recover all of its losses and produce dazzling gains for investors in 2020. In March, the biotech company reported strong phase 3 results for its flu vaccine, NanoFlu, which CEO Stan Erck said could be a "game-changer for the prevention of influenza." 

And in July, Novavax received $1.6 billion in funding from the U.S. government to advance the testing, development, and manufacture of its experimental coronavirus vaccine, NVX-CoV2373. After NVX-CoV2373 demonstrated promising results in a phase 1 study in August, Novavax would go on to sign supply deals with India, Japan, South Korea, and the U.K. 

These announcements fueled a massive rally in Novavax's share price. The stock is now up an incredible 3,360% so far in 2020. So, for every $1,000 you invested in Novavax's stock at its lows in January, you'd have $34,600 today.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.