In September, the Centers for Disease Control and Prevention predicted that by the third quarter of next year, enough vaccines will be available for the coronavirus that Americans should start to be able to return to their normal lives. But that doesn't mean that COVID-19 will be gone by then. And the estimate could change depending on spikes in cases -- and on whether companies developing vaccines run into problems along the way.

That's why investing in coronavirus stocks could still be a good move for investors today. Any company that's busy as a result of COVID-19 is likely to remain that way for the foreseeable future. And one of those companies is drugmaker Gilead Sciences (GILD 3.18%). Let's look at whether its stock is a good investment during the pandemic.

What makes Gilead a good coronavirus stock to buy

Treating patients who have COVID-19 will be necessary until the disease is gone. And Gilead's drug remdesivir was one of the early treatment options that medical experts were excited about. On May 1, the U.S. Food and Drug Administration (FDA) granted emergency use authorization (EUA) to remdesivir for use in patients with severe COVID-19 (where blood oxygen is low or a ventilator is needed). Nearly four months later, on Aug. 28, the FDA expanded that authorization to include all patients who are in hospitals due to COVID-19.

Two hospital workers in personal protective equipment, consulting over a clipboard

Image source: Getty Images.

In April, the National Institute of Allergy and Infectious Diseases (NIAID) released the results of a study on remdesivir that showed that hospitalized patients with advanced COVID-19 who took the drug recovered 31% more quickly than others, speeding up recovery time by four days. A study released earlier this month in the New England Journal of Medicine found that hospitalized COVID-19 patients taking remdesivir recovered five days quicker, compared with median recovery times, than patients who only received a placebo. Meanwhile, another study found that when remdesivir was taken with Eli Lilly's drug Olumiant, which treats rheumatoid arthritis, it could help accelerate recovery time by an additional day.

It's clear that remdesivir is effective in reducing the recovery time of patients with COVID-19, so it could be an attractive coronavirus stock to own. Demand is likely to remain strong for the foreseeable future. And the company's CEO, Daniel O'Day, told CNBC that Gilead has "ample supply" of the drug, and that by the end of October it will have enough to supply patients around the world.

Why the stock isn't soaring

Despite the optimism around remdesivir, Gilead's shares aren't taking off as much as earlier in the year.

The problem with remdesivir is that while it has improved recovery times for patients, it's not a cure; remdesivir is not able to prevent death in many cases. The most recent report showed that by day 29, the mortality rate with remdesivir was 11.4% compared to 15.2% with the placebo. And so while there's been progress in treating COVID-19, the results have been a bit underwhelming, and not the solution that investors and medical experts were likely hoping for.

There are also alternatives, such as Regeneron's (REGN 0.84%) REGN-COV2 antibody cocktail, which President Donald Trump took under a "compassionate use" request (the company is currently seeking EUA from the FDA) when he contracted COVID-19. Early results from a study are showing that Regeneron's antibody treatment appears to be effective in reducing the viral levels of patients with the coronavirus, while also improving symptoms in people who aren't yet hospitalized. Eli Lilly also issued a press release earlier this month saying that its own antibody treatments were effective in battling COVID-19, as they've reduced viral loads and prevented hospitalizations due to COVID-19.

With more options available to COVID-19 patients and remdesivir not the silver bullet many people thought it might be for the coronavirus, it's easy to see why investors aren't as bullish on Gilead anymore.

Does Gilead's cheaper price make it a buy?

Gilead's stock is trading near its 52-week low of $61.65 and is down around 1% year to date, while the S&P 500 is up 9%. Its forward price-to-earnings (P/E) ratio of 9 looks cheap for value investors, but that's also around the multiple they were paying for Gilead's stock a year ago.

Remdesivir has been available for months for COVID-19 patients. But without clear evidence that it can stop the coronavirus and significantly improve mortality rates, there's no real reason to be bullish on it, especially as more treatment options become available. Gilead may be a decent investment if you're looking for a good dividend stock -- it currently yields more than 4.2%, well above the S&P 500's average of about 2%. But for coronavirus stocks, there are simply better options out there.