I don't use the word "incomparable" very often. That's mainly because most things don't fit the description. It's easy to find comparisons for pretty much everything. 

However, I think it's appropriate to describe 2020's race to develop coronavirus vaccines as incomparable. There has never been so much progress made to fight a global pandemic in such a short period. 

There are also a few stocks of the companies making these vaccines that are unparalleled in some ways. Here are three extraordinary coronavirus vaccine stocks that you can buy right now.

Physician holding a syringe and needle with a COVID-19 vaccine vial

Image source: Getty Images.

1. Johnson & Johnson

Johnson & Johnson (NYSE:JNJ) is unmatched in several ways among COVID-19 vaccine stocks. It's by far the largest in terms of market cap and revenue. It's the only Dividend Aristocrat in the group. But there's also something unique about J&J's coronavirus vaccine itself -- at least among the vaccines that are either in late-stage development or that have already won emergency use authorization (EUA).

All of the other leading COVID vaccines require two doses administered three or four weeks apart. Johnson & Johnson's JNJ-78436735, however, requires only one dose. That could give J&J a big competitive advantage if the experimental vaccine wins EUA.

Actually, though, Johnson & Johnson's coronavirus vaccine isn't the main reason to consider buying this stock. The best reason to invest in J&J is that it provides the kind of stability that few other stocks can. The company has been in business since 1886. It's weathered recessions, depressions, world wars, and huge changes in healthcare.

Another part of the stability J&J offers is its sheer size. It operates three multibillion-dollar business segments spanning consumer health, medical devices, and pharmaceuticals. No other healthcare company is as diversified as J&J is. Risk-averse investors seeking to profit from COVID-19 vaccines won't find a steadier choice than Johnson & Johnson.

2. Novavax

Johnson & Johnson won't be very attractive to investors looking for sizzling growth. Thankfully, there's a coronavirus vaccine stock that has already generated fantastic gains this year and could soar much higher in 2021 and beyond. That stock is Novavax (NASDAQ:NVAX).

So far this year, Novavax stock has skyrocketed well over 3,000%. That puts the biotech in a league of its own among COVID-19 vaccine makers with late-stage candidates. Even with this remarkable performance, though, Novavax's market cap still stands below $10 billion.

There's also another way that Novavax stands out from the pack. It's the only company with late-stage COVID-19 and flu vaccine candidates. The biotech reported impressive results from a phase 3 study of experimental flu vaccine NanoFlu earlier this year.

Why is this a big deal? Novavax is exploring the potential to combine the two vaccines for post-pandemic use. If COVID-19 turns out to be as seasonal as the flu, that could be a winning formula for this high-flying biotech stock. Even if not, Novavax could soon have two blockbuster vaccines on the market.  

3. Arcturus Therapeutics

For investors who like even more thrills and adventure, check out Arcturus Therapeutics (NASDAQ:ARCT). I view Arcturus as the most intriguing dark horse in the coronavirus vaccine race right now.

The two COVID-19 vaccines that have already won EUA are based on messenger RNA (mRNA) technology -- as is Arcturus' ARCT-021. That could bode well for the chances that the company's vaccine candidate will be safe and highly effective. It doesn't, however, give Arcturus a unique angle.

What does make Arcturus special, though, is that ARCT-021 is a single-dose mRNA vaccine. If Johnson & Johnson's single-dose vaccine doesn't achieve really high efficacy, it could put Arcturus at the center of attention, assuming all goes well with its clinical testing of ARCT-021.

Arcturus lags behind J&J, Novavax, and other current leaders in COVID-19 vaccine development. The biotech is currently evaluating its experimental vaccine in phase 1/2 clinical testing. However, Arcturus hopes to quickly advance ARCT-021 into later-stage studies.

Israel and Singapore have already inked supply deals for the vaccine. I think more countries will line up to buy from Arcturus if its clinical testing goes well. This small biotech stock will almost certainly become much larger next year if that happens. 

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.