There's no beating around the bush -- the coronavirus disease 2019 (COVID-19) pandemic has been a life-altering event for billions of people worldwide for more than a year. There have been nearly 187 million cases confirmed globally, leading to more than 4 million deaths. 

But if there's one bright light among the challenges we've collectively faced, it's been the swiftness to which effective COVID-19 vaccines were developed. Whereas most therapies take a decade to make the full trip from lab conceptualization to fully approved drug, some pharmaceutical stocks and biotech companies were able to complete this task in under a year.

As you can imagine, life-saving vaccines have the potential to generate a lot of revenue for the companies developing them. Based on what we've been told from these drugmakers, what we can infer from first-quarter sales, and what we can "guestimate" from Wall Street's consensus forecasts, here's how much revenue each drugmaker is on track to generate from COVID-19 vaccines in 2021.

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

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Pfizer/BioNTech: $40.7 billion, combined

The unquestioned global sales leader is the messenger-RNA-based COVID-19 vaccine developed by Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX), known scientifically as BNT162b2. In November, when Pfizer and BioNTech concluded their phase 3 study, their vaccine was shown to be 95% effective against the now-original strain of the disease 28 days after the first dose. This incredible efficacy helped the duo win emergency-use authorization (EUA) in the U.S. and elsewhere. 

After reporting $3.46 billion in first quarter sales of BNT162b2, Pfizer increased its COVID-19 vaccine revenue forecast to $26 billion from a prior estimate of $15 billion. Meanwhile, BioNTech recorded 1.75 billion euros (about $2.08 billion) in COVID-19 alliance revenue and product sales, and ultimately upped its own forecast to 12.4 billion euros ($14.7 billion), from a previous projection of 10 billion euros. On a combined basis, Pfizer and BioNTech foresee $40.7 billion in sales for BNT162b2 in 2021. 

Perhaps the craziest thing is this figure might still be conservative. Pfizer's $26 billion vaccine estimate is based on existing contracts to deliver 1.6 billion doses this year. However, the company intends to produce up to 2.5 billion vaccines in 2021. If some of these additional doses find a buyer, Pfizer and BioNTech could easily generate over $50 billion in sales this year from BNT162b2. 

A lab technician using a multi-pipette device to place liquid samples into a row of test tubes.

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Moderna: $19.2 billion

The other bona fide superstar on the COVID-19 vaccine front is biotech stock Moderna (NASDAQ:MRNA). Moderna's messenger-RNA COVID-19 vaccine, mRNA-1273, was equally impressive in clinical trials. In late November, the company released the primary efficacy analysis of its phase 3 COVE study, which demonstrated a vaccine efficacy of 94.1%, along with 100% efficacy against severe forms of COVID-19. 

In the first quarter, ended in March, Moderna racked up $1.73 billion in vaccine sales, as well as $194 million in grant revenue. More importantly, the company foresees vaccine production coming in between 800 million and 1 billion doses in 2021. Considering that Moderna's vaccine is the high-water mark in terms of price per dose, it's expected to generate $19.2 billion in revenue. That's actually up $800 million from the company's prior sales forecast for mRNA-1273 earlier this year. 

Since Moderna wasn't generating product revenue prior to the pandemic, it's arguably the most direct way for investors to try to benefit from the global vaccination campaign.

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AstraZeneca: $1.5 billion to $2.5 billion (author estimate)

Whereas Pfizer/BioNTech and Moderna have been forthcoming with sales projections for their COVID-19 vaccines, the same can't be said for U.K.-based pharmaceutical company AstraZeneca (NASDAQ:AZN). The company's vaccine (AZD1222), known as Vaxzevria in Europe, where it has EUA approval, achieved an average vaccine efficacy of 70%, based on trial data that was presented late last year. 

In the first quarter, Vaxzevria generated $275 million in sales for AstraZeneca, with $224 million originating in Europe, $43 million coming from emerging markets, and $8 million derived from the rest of the world. In total, it delivered 68 million doses. This means a dose of AstraZeneca's vaccine is being sold at cost, which is around $4. 

But, as noted, the company hasn't provided any full-year sales guidance for its COVID-19 vaccine. While CEO Pascal Soriot has stated that his company is on track to eventually reach 200 million doses of production on a monthly basis, it's not clear what the demand for AstraZeneca's vaccine will look like outside of Europe. On one hand, any vaccine with an efficacy of 70% is better than nothing. But with Pfizer/BioNTech and Moderna performing so much better from an initial efficacy standpoint, and AstraZeneca's vaccine being linked to very rare cases of blood clots, my personal expectation is that sales improve in subsequent quarters, though they don't soar. 

A lab technician holding a vial of blood in their left hand while making notes on paper with their right hand.

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Johnson & Johnson: $1 billion to $3 billion (author estimate)

Like AstraZeneca, Johnson & Johnson (NYSE:JNJ) has pledged to sell its COVID-19 vaccine at cost for as long as the pandemic is ongoing. The J&J vaccine, known scientifically as JNJ-78436735, is the only single-dose vaccine on this list, and it was found to be 66.3% effective in clinical studies at preventing laboratory-confirmed COVID-19 infection. 

During the first quarter, Johnson & Johnson reported $100 million in sales of its COVID-19 vaccine solely from the United States, with each dose costing about $10. But the J&J vaccine is also being examined for possible rare links to thrombosis in patients. This led to a temporary sales halt in the U.S., and it delayed the company's vaccine rollout in Europe. 

There's obvious value with the J&J vaccine for folks who dislike the idea of getting two shots. Likewise, it's also a clinically proven safer option than not getting a vaccine at all. However, it's nominally lower initial efficacy and the U.S. blood-clotting scare are bound to lower its sales potential in the near-term. While I'd expect sales to pick up in 2022, especially in emerging markets, J&J's lack of sales guidance for its vaccine tells the story that it won't be a huge contributor in 2021. My prediction, based on its slow start, is anywhere from $1 billion to $3 billion in global sales.

A physician administering a vaccine into the left arm of a patient.

Image source: Getty Images.

Novavax: $2.16 billion, Wall Street estimate

Last, but not least, I'm including clinical-stage biotech company Novavax (NASDAQ:NVAX), because it looks to have a very good shot (pun intended) at gaining EUA for its COVID-19 vaccine candidate NVX-CoV2373 during the third quarter.

In March, Novavax reported trial data from a large-scale study in the U.K., with NVX-CoV2373 demonstrating 96.4% efficacy against the original strain of the virus and 89.7% overall efficacy, with other variants included.  Then, in June, the company lifted the hood on its phase 3 trial conducted in the U.S. and Mexico, which demonstrated almost identical efficacy of 90.4%. With a favorable safety profile, it looks to have a very good chance of gaining EUA in the U.S., U.K., and Europe. 

The big issue for Novavax hasn't been trial data. Rather, it's been the delays. It was initially expected to file for EUA in the second quarter. Further, the company may not be up to full vaccine production until sometime in the fourth quarter. Thus, it's really hard to say how quickly sales could ramp up in 2021 for Novavax -- and Wall Street's full-year sales estimates illustrate this challenge. Of the five analysts to offer a revenue estimate, the totals range from a low of $897 million to a peak of $3.05 billion. Based on the average estimate, Wall Street has Novavax dialed in for more than $2.1 billion in COVID-19 vaccine sales in the second half of 2021.

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.