Here's how the top 3 coronavirus vaccines compare when it comes to efficacy, cost, and more

• In November, AstraZeneca and Oxford University released preliminary results from late-stage trials that showed that their vaccine candidate was about 70% effective in protecting against COVID-19.
• The vaccine joins two others — one made by Pfizer and BioNTech, another by Moderna — as frontrunners in the race for a vaccine to address the coronavirus pandemic.
• There are key differences between the three vaccines, in terms of cost, distribution, regulatory approval, and more.

As the race for a safe and effective COVID-19 vaccine continues, three candidates have become frontrunners: one from Pfizer and BioNTech, another from Moderna, and another from AstraZeneca and Oxford University.

But each of these candidates has important differences, with widespread implications for their distribution and use. Take a look at Business Insider's chart below to compare.

Cost

AstraZeneca's vaccine is significantly cheaper than Moderna's and Pfizer's, AP reported. Unlike its two competitors, AstraZeneca is the only one of the three to pledge not to make a profit from the vaccine during the pandemic. Pfizer's vaccine clocks in at about $20 per dose, Moderna's at $15 to $25 a dose, and AstraZeneca's jab about $4, based on each company's contracts with the US government.

Read more: Pharmacies, doctor's offices and hospitals are gearing up to give coronavirus vaccines to millions of Americans. Here's how they're preparing and how much they stand to profit along the way.

Distribution

The potential success of the AstraZeneca vaccine is especially important for nations outside of the US and the UK. Of the three candidates, AstraZeneca is the only one to have already struck a deal with COVAX, a global initiative to distribute COVID-19 vaccines equitably, including to low-income nations, according to data from the Duke Global Health Innovation Center.

"The Oxford/AstraZeneca vaccine is really good news for the rest of the world," said Andrea Taylor, assistant director of programs at Duke Global Health Innovation Center, according to CNN.

COVAX has placed an order for 300 million doses from AstraZeneca. Meanwhile, Pfizer-BioNTech isn't part of the COVAX initiative, and Moderna is part of the COVAX project, but has not "quite aligned with them on how many doses and when those doses would be available," according to Axios.

Storage

Of the three, Pfizer's vaccine will be the most difficult to store and distribute. The vaccine must be kept at -94 degrees Fahrenheit for storage, and can be kept in a special dry ice case for up to 30 days, Pfizer says. To make matters more difficult, dry ice is already in high demand, according to WBUR.

Meanwhile, Moderna's vaccine can be kept in a standard freezer, at -4 degrees Fahrenheit long term, and can survive in a standard refrigerator for about a month. Of the three, AstraZeneca's vaccine candidate is the hardiest, since it's able to be refrigerated for up to 6 months, according to AstraZeneca.

Efficacy & Approval

While AstraZeneca's vaccine has obvious advantages, due to its cost and ease of distribution, the vaccine has also come under fire for concerns about the way it reported results from its trial. After announcing that its vaccine was 62% effective for a regimen of 2 full doses a month apart and 90% effective for a regimen of a half dose followed by a full dose, questions began to be raised about AstraZeneca's data and disclosures, according to The New York Times.

AstraZeneca's vaccine likely won't be authorized in the US until after shots from Pfizer and Moderna, because the company's late-stage trial is still ongoing here. Pfizer was the first of the three to file for FDA emergency use authorization, followed by Moderna. Pfizer's vaccine was approved for emergency use in the UK on Wednesday.