The so-called "V-Day" (Vaccine Day) has finally arrived. Following months of development and testing, the U.S. Food and Drug Administration (FDA) approved the very first coronavirus disease 2019 (COVID-19) vaccine for emergency use authorization (EUA) late last week, paving the way for the first round of inoculations, which began on Monday, Dec. 14.

Pfizer's (NYSE:PFE) and BioNTech's (NASDAQ:BNTX) vaccine, BNT162b2, was the first to get the green light from the FDA for emergency use, with Moderna's (NASDAQ:MRNA) mRNA-1273 expected to follow within the next week, or possibly sooner.

Now that COVID-19 vaccines are finally rolling out, Americans can turn to the next most pressing question: How much will they cost?

While President-Elect Joe Biden has proposed making coronavirus vaccines free for Americans, the actual cost to the federal government will vary pretty dramatically between vaccine candidates. Let's take a closer look at the cost variances of the four late-stage or EUA-approved players.

Multiple syringes lying atop a messy pile of one hundred dollar bills.

Image source: Getty Images.

Pfizer/BioNTech

The first vaccine to get EUA from the FDA will have a cost per dose of $19.50. That's derived from selling 100 million doses to the U.S. Department of Health and Human Services for $1.95 billion. Since BNT162b2 is given in two doses multiple weeks apart, we're talking about a $39 total cost for treatment. 

Al told, $39 seems like a bargain for a vaccine that delivered 95% vaccine effectiveness (VE) in late-stage clinical trials. At the moment, a 95% VE sits head and shoulders above all other vaccine developers.

Perhaps the biggest concern for this promising COVID-19 vaccine is getting it to consumers. The Pfizer/BioNTech vaccine needs to be kept at ultra-cold temperatures during transport to remain stable (close to minus 100 degrees Fahrenheit). While there are solutions being implemented, such as the use of dry ice during transport, the logistical challenges of BNT162b2 have opened the door for other COVID-19 vaccine candidates to eventually take market share.

A physician administering a vaccine to an elderly woman.

Image source: Getty Images.

Moderna

Moderna's coronavirus vaccine is also quite promising -- and relatively costly, when compared to its peers. According to CEO Stephane Bancel, Moderna is planning to charge between $25 and $37 per dose of mRNA-1273, depending on how much of the product is purchased at a given time. The more that's bought, presumably, the lower the per-dose cost. Since this is also a two-dose treatment, the full cost of Moderna's vaccine ranges from $50 to $74. 

If you're wondering why consumers or countries might choose Moderna over its rivals, look to both VE and safety. Moderna's vaccine produced a nearly identical VE of 94.1% in the late-stage COVE trial. Perhaps even more important, grade 3 adverse events were minimal, potential giving Moderna a one-up over Pfizer/BioNTech in the safety department.

Moderna's mRNA-1273 is expected to receive a vote from the FDA's advisory panel on Dec. 17. If all goes well, it could receive EUA and begin distribution shortly thereafter.

A lab researcher using a pipette to place samples under a high-powered microscope.

Image source: Getty Images.

AstraZeneca/Oxford

Another vaccine candidate in the mix is AZD1222, which was developed by Big Pharma AstraZeneca (NASDAQ:AZN) and Oxford University. AstraZeneca has made the decision to supply its vaccine at cost (i.e., without generating a profit). This implies a per-dose cost of between $3 and $4, with a grand total expenses of $6 to $8. 

With a cost that's well below its peers, you'd think the AstraZeneca/Oxford vaccine would see plenty of demand. However, that's not a given following the release of late-stage VE data on AZD1222. One arm of the trial provided a VE of 62% for patients receiving two full doses at least one month apart. Another arm, which involved an initial half dose followed by a full dose at least a month later, led to a 90% VE. The difference in VE between the cohort with two full doses and the cohort with an initial half dose has left the scientific community a bit baffled.

On a combined basis, AZD1222 achieved a VE of 70%. That's still better than the average effectiveness of an influenza vaccine (typically 50% to 60%), but it pales in comparison to the Pfizer/BioNTech and Moderna vaccines.

A doctor speaking with a young male patient.

Image source: Getty Images.

Johnson & Johnson

Finally, there's JNJ-78436735, which is being developed by the largest healthcare stock by market cap in the U.S., Johnson & Johnson (NYSE:JNJ). In August, the Biomedical Advanced Research and Development Authority agreed to buy 100 million doses of Johnson & Johnson's vaccine for "over $1 billion." This works out to perhaps $10, or just a smidge over, per dose. 

Phase 1/2a clinical trial results from October for JNJ-78436735 showed detectable levels of antibodies in 99% of trial participants, with 98% of participants positive for neutralizing antibodies. Johnson & Johnson anticipates reporting its phase 3 trial results in January, but will lag the other three developers in potentially launching its vaccine.

However, J&J has one big advantage over its peers: Its vaccine is only administered in a single dose. If Johnson & Johnson's late-stage trial were to produce a VE that's somewhat similar to Pfizer/BioNTech and Moderna, there's little question that its total cost and the convenience of a single shot would vault it to front-runner status.

It's going to be an interesting next couple of months, to say the least.