'Tis the season for... coronavirus stocks? Yep. With so much happening on the development and regulatory fronts, now's a great time to look at investing in coronavirus stocks.

But which stocks are the best picks? Here are three top coronavirus stocks to buy in December.

Red gift box containing a device labeled "vaccine."

Image source: Getty Images.

1. Pfizer

There's no disputing that Pfizer (PFE -0.19%), along with its partner BioNTech (BNTX -0.45%), sits atop the COVID-19 world right now. Its BNT162b2 has already picked up authorizations in the U.K. and Canada. The clock is ticking on a likely U.S. emergency use authorization (EUA).

BNT162b2 should make a lot of money for Pfizer. Bernstein analyst Ronny Gal predicts the vaccine will rake in $25 billion over the next five years. That could even be on the low end since Gal's estimate assumes booster shots are needed only every three years. 

Pfizer recently completed the long-awaited merger of its Upjohn unit with Mylan. This transaction removed Upjohn's slate of older drugs with declining sales from Pfizer's lineup and set up the company for stronger growth going forward.

With its shares trading at less than 14 times expected earnings, Pfizer is a lot cheaper than most S&P 500 stocks. It also offers an attractive dividend that currently yields close to 3.6%. I think that this big pharmaceutical stock stands out as one of the best picks for risk-averse investors looking to profit from the coronavirus vaccine race.

2. Novavax

More aggressive investors might not be too excited about buying Pfizer. However, there's another great stock for these investors that I predict could be the biggest winner in the COVID vaccine market next year -- Novavax (NVAX -0.95%).

The biotech's shares have skyrocketed close to3,000% year to date. Much of this massive gain was fueled by excitement over Novavax's coronavirus vaccine candidate NVX-CoV2373. Several Wall Street analysts referred to the experimental vaccine as potentially best in class after Novavax reported terrific early stage results.

Novavax is currently evaluating NVX-CoV2373 in a late-stage study in the U.K. It should report interim results from that study in early 2021. The biotech's planned U.S. late-stage study has been delayed while manufacturing questions are answered, but could begin within the next few weeks.

Good news for its COVID-19 vaccine would send Novavax's share price into orbit. But the biotech also has another promising pipeline candidate, flu vaccine NanoFlu, that could be a blockbuster. Novavax's remaining hurdle to file for U.S. approval of NanoFlu is a manufacturing lot consistency trial.

3. Arcturus Therapeutics

Is there a good coronavirus stock to buy for super-aggressive investors? I think so. Check out Arcturus Therapeutics (ARCT -3.40%), an up-and-coming biotech that I view as the dark horse to really watch in the coronavirus vaccine race.

Arcturus' COVID-19 vaccine ARCT-021 uses a messenger RNA (mRNA) approach like Pfizer's BNT162b2 and Moderna's mRNA-1273. I suspect that ARCT-021 could have a high efficacy rate similar to BNT162b2. However, Arcturus' vaccine holds a big advantage over these vaccines: It requires only one dose.

It's still early for ARCT-021. Arcturus is currently evaluating the experimental vaccine in a phase 1/2 study. However, the company hopes to soon move forward with late-stage testing in Singapore. Speaking of Singapore, it's one of two countries (Israel is the other) to sign supply agreements with Arcturus for its COVID vaccine.

Arcturus stock has soared 875% so far this year. Even with this huge jump, the company's market cap remains at only around $2.6 billion. If ARCT-021 delivers on its potential, Arcturus will be a huge winner for investors willing to take on the higher level of risk associated with the small biotech.