When the history books are written about the COVID-19 pandemic, two biotechs will almost certainly be included. Gilead Sciences (GILD 3.62%) became the first company to win emergency use authorization from the Food and Drug Administration for a new drug for treating COVID-19, remdesivir (which is marketed under the brand name Veklury). Moderna (MRNA -3.58%) ranks as one of the leaders in the race to develop a coronavirus vaccine.

So far this year, Moderna has been by far the bigger winner in terms of stock performance. Its shares have soared more than 240%, while Gilead's shares are down year to date. But which of these coronavirus-focused stocks is the better pick for long-term investors?

Dollar sign surrounded by coronavirus molecules.

Image source: Getty Images.

The case for Gilead Sciences

Veklury seems on track to become another blockbuster drug for Gilead by the end of this year, even before it wins full FDA approval. The big question, though, is how much money the COVID-19 therapy will make for Gilead over the long run.

That total could be boosted considerably if Gilead's testing of an inhaled version of remdesivir is successful. The biotech is currently evaluating an inhaled version of the drug in a phase 1 clinical study targeting patients in outpatient settings, such as nursing homes. 

However, the main reason for investors to consider buying Gilead isn't its coronavirus program. Gilead remains a market leader in treating HIV and hepatitis C. It's also quickly establishing a major presence in the cancer treatment market.

Gilead's 2017 acquisition of Kite immediately launched the biotech to the forefront of the cancer cell therapy arena. The company's recent business development efforts, especially its pending acquisition of Immunomedics, hold the potential to make Gilead a major player in treating solid tumors.

Don't be surprised if Gilead extends its dominance in HIV even more, though. It's evaluating long-acting capsid inhibitor lenacapavir in a phase 3 clinical study targeting heavily treatment-experienced individuals with HIV. Gilead's pipeline also includes four candidates that the company thinks could potentially cure HIV.

Even with the Immunomedics acquisition, Gilead will have an ample cash stockpile. The company shouldn't have any problems keeping its dividends flowing and still funding smaller deals in the future to boost growth.

The case for Moderna

Moderna belongs to an elite group of companies with COVID-19 vaccine candidates in late-stage testing. The biotech thinks that it could have preliminary results for its candidate, mRNA-1273, by November. It's quite possible that Moderna's vaccine will become one of the first two to win FDA emergency use authorization.

The company stands to make a lot of money very quickly if mRNA-1273 receives a regulatory green light. Moderna landed a $1.525 billion deal with the U.S. government to supply 100 million doses of its coronavirus vaccine, with an option for the U.S. to buy another 400 million doses. 

Moderna also has signed an agreement with Canada to supply 20 million doses of mRNA-1273. It's in discussions with the European Commission and Japan about potential supply deals as well.

Success for mRNA-1273 would go a long way toward validating Moderna's entire messenger RNA (mRNA) platform. The company's pipeline includes six other mRNA prophylactic vaccines in clinical testing, plus two in preclinical development. Moderna recently announced plans to develop a flu vaccine using its mRNA technology.

The biotech's opportunities aren't just limited to vaccines to prevent viral infection. Moderna has five clinical-stage mRNA programs targeting cancer and another program targeting coronary artery disease. The company is partnering with AstraZeneca on two of those programs and with Merck on two others. 

Better coronavirus stock?

I think that your investing style will dictate which of these biotech stocks you like better.

Investors who are more risk-averse will probably prefer Gilead Sciences. It's profitable, has multiple blockbuster products on the market already, and pays a dividend. More aggressive investors, though, might find Moderna more to their liking. The stock arguably has greater growth prospects than Gilead does, albeit with a much higher risk level, too.

My personal nod goes to Moderna. I'm not convinced that Gilead will be able to deliver enough growth to move its share price appreciably, especially if it fails to win FDA approval for filgotinib in treating rheumatoid arthritis. On the other hand, I'm cautiously optimistic about Moderna's chances with mRNA-1273 and think a win for the vaccine could fire up investors' enthusiasm about the rest of the company's pipeline.