Which coronavirus vaccine will you get?

• Pfizer and Moderna's coronavirus vaccines are very similar in terms of how they were made, and their safety and efficacy.
• There may be slight differences in how they work in older populations, but experts say more data is needed before we make that conclusion.
• Because Pfizer's needs to be stored at very cold temperatures, it will be distributed at larger institutions while Moderna's vaccine may be more likely to be distributed at smaller clinics and pharmacies.
• As vaccine rollouts continue, and more enter the pool, experts will learn more about whether some vaccines are more effective in certain populations.

Both the Pfizer-BioNTech and Moderna coronavirus vaccines are now authorized for emergency use in the United States, meaning expert panels have agreed their benefits outweigh their risks given what's currently known and the urgent need to combat the pandemic.

More vaccines are being tested, and some are expected to join the list of vaccines distributed across the US.

"The plan is that we have more than one 'winner,'" Dr. Anthony Fauci said on the first episode of a new podcast hosted by Microsoft founder Bill Gates and actress Rashida Jones.

But with multiple vaccines, who will receive which one, and does it matter? President-elect Joe Biden and Vice President Mike Pence have both gotten the Pfizer vaccine, for example, while the nation's top infectious-disease expert Dr. Anthony Fauci is set to receive Moderna's Tuesday.

At the moment, experts say, choice is a luxury we don't have or need.

"Right now, we are trying to maximize getting out the [authorized] vaccines," California State Senator and pediatrician Dr. Richard Pan told Insider. "Whichever vaccine is offered to you first is the one you should take."

The currently authorized vaccines are very similar and, for now, people won't have a choice

Both vaccines are made from mRNA and require two doses.

Both seem to be quite safe and highly effective, with clinical trials finding Pfizer's vaccine 95% effective, and Moderna's 94.1% effective, at preventing symptomatic disease.

The shots also seem pretty comparable in their ability to fight severe infections and reduce deaths, and share the same major unknowns. For instance, we don't know how long either protects people, whether they also block against asymptomatic spread, or how safe and effective they are in pregnant people and children.

One main, though minor, difference right now between the two vaccines seems to in side effects, with participants in Moderna's trial more readily reporting reactions including injection site pain, fatigue, headache, and muscle pain.

Pfizer's data suggests its vaccine may also have a slight edge on Moderna's when it comes to protecting older people, but experts say time will tell if that is actually the case, given the small sample size of older people in Pfizer's trial.

On the other hand, as Business Insider's Hilary Brueck and Andy Dunn reported, Moderna's shots may be superior in combatting severe illness.

Still, those are moot points right now, as individuals don't have a choice between the two vaccines - and that's OK.

"There is not much difference between them, so either one is a good option," Annmarie Munana, master instructor of nursing at Chamberlain University in Chicago, where she serves on the city's Department of Public Health - Scientific COVID-19 Vaccine Work Group, told Insider.

It is important, however, to make sure your second dose is made by the same manufacturer as your first, she said.

The Pfizer vaccine will need to be stored at larger institutions

The one key difference between the two vaccines that could affect their current distribution is how they're stored, Pan said. The Pfizer vaccine needs to be kept at very cold temperatures, and so can only be given out at larger institutions that can handle that requirement.

The Moderna vaccine, by contrast, "does not require low temperature storage," he said, "so you'll likely see this vaccine available in clinics and pharmacies."

As we learn more, different populations may receive different shots

As Pfizer and Moderna's clinical trials continue and experts track their rollouts, they'll learn whether some vaccines are more suitable for certain people than others.

Later on, as additional vaccines - which may be made differently than Pfizer and Moderna's and come with different side effects, for instance - are added to the pool, who gets which one could become more deliberate.

"Once additional vaccines are approved and are more plentiful and widely distributed, there may be more flexibility and options, and it will be important for patients and their clinicians to discuss the best option for them," Munana said.

For instance, Fauci said on Gates' and Jones' podcast, "there may be one vaccine that seems to work better in the elderly than in the young, and one may work better in children than it works in the elderly. When you learn that, and it will take some time to learn that, you may have more of a selective distribution, depending on the demographic group."

Meantime, the fact that multiple safe, effective vaccines are being distributed in the US less than a year after the novel coronavirus entered the human population is worth appreciating.

"Remember, this is the first time our country has done this type of nationwide emergency vaccine distribution," Munana said. "It is impressive to see so many industries from pharma and technology, to transportation and medical supplies, come together for one common distribution effort."