Coronavirus vaccines compared: What to know about shots from Moderna and Pfizer, from safety to side effects
Moderna and Pfizer have COVID-19 vaccines that are safe and effective, based on testing in tens of thousands of people. But there are differences.The Food and Drug Administration granted emergency use authorization for Pfizer's two-shot vaccine last week, and agency regulators are expected to greenlight Moderna's very similar two-dose mRNA shot course later this week. An FDA expert panel will meet Thursday to discuss and vote on Moderna's shot, teeing up an agency decision that could come as soon as Friday.
Moderna vs. Pfizer Covid-19 vaccine: Which is better?
The short answer is neither. In December, the Food and Drug Administration (FDA) released the news the country had been waiting for: The new Covid-19 vaccine, developed by Pfizer and its partner BioNTech, had been approved. A week later, a second vaccine from Moderna was also approved. And now that the vaccine roll-out has begun (albeit slowly), you might be wondering which Covid vaccine is better.
(This is when the Covid-19 vaccine will likely reach you.)
Should you hold off on one vaccine in order to wait for the other? "Absolutely not," says Reynold Panettieri, MD, a professor at the Rutgers Robert Wood Johnson Medical School and director of the Rutgers Institute for Translational Medicine and Science in New Brunswick, New Jersey. "No difference has been shown."
How Moderna's coronavirus vaccine differs from Pfizer's
Moderna's coronavirus vaccine is similar to the Pfizer-BioNTech vaccine that was authorized and shipped out to Americans earlier this week. But there are a few key differences. Most importantly, Moderna's vaccine can be stored in normal freezers and does not require a super-cold transportation network, making it more accessible for smaller facilities and local communities. The US Food and Drug Administration's vaccine advisory committee meets Thursday to review whether to recommend emergency use authorization for Moderna's vaccine, with the FDA's decision expected by Friday.
Basically, the vaccines are very similar in terms of how they work and how effective they are. So get vaccinated with whatever vaccine is available to you. "The sooner that you are starting to build immunity the better it is for you, for your family, for your community, and for the world," says Anne Rimoin, PhD, a professor of epidemiology at UCLA Fielding School of Public Health in Los Angeles. "You should take whatever vaccine you can get first."
Here's a deeper dive into how the two vaccines, Moderna vs. Pfizer compare. (Also, be sure to avoid these Covid-19 vaccine conspiracy theories.)
Both vaccines are extremely effective. In studies published in December 2020 in The New England Journal of Medicine, the Pfizer vaccine was shown to be 95 percent effective in a clinical trial of over 43,000 participants. Moderna's vaccine was 94 percent effective in a trial of over 30,000. "Both are nearly as effective and no different in adverse effects or duration of protection," Dr. Panettieri says. "Get the one you can."
Covid-19 vaccine side effects, explained
What the Moderna and Pfizer/BioNTech vaccines may feel like.On Thursday, a committee that advises the Food and Drug Administration will meet to determine whether the Moderna vaccine should get an emergency use authorization. Ahead of the decision, the agency shared the most comprehensive data to date on what we know about the shot. The same process happened last week with the Pfizer/BioNTech vaccine, which is now being rolled out across America following an EUA Friday night.
(Find out what it’s like to participate in a Covid-19 vaccine trial.)
How is each administered?
Both are given in a series of two shots. They differ slightly in the spacing in between, with Pfizer's second dose given 21 days after the first, and Moderna's 28 days later. In general, you should get the same vaccine for both your first and second dose, according to The New England Journal of Medicine. (Taking one dose of each hasn't been studied.)
What's unknown about each vaccine?
For both vaccines, there are some things scientists don't yet have a lot of information on. "In clinical trials, both vaccines seemed to reduce the risk of severe Covid-19 disease," Dr. Rimoin says. "We still do not know if either prevents asymptomatic infection with the SARS-CoV-2 virus." That's why it's still important to keep wearing face masks and practice social distancing until enough people are vaccinated.
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More than a dozen frontrunners have reached late-stage clinical trials.Many of the other candidates, however, will fail somewhere along the vaccine development pipeline, which includes three rounds of clinical trials with increasingly large pools of volunteers to assess their safety, efficacy, and ability to prompt a response from the immune system. And for those that achieve authorization, there remain important questions that we’ll need more time and further research to answer, including how long the immunity they offer from COVID-19 lasts.
We also don't know exactly how long the vaccine immunity will last; or if one is better than the other against the mutant strains of Covid-19 we're starting to see. Pfizer and Moderna have both had initial promising research (not peer-reviewed) on how well the vaccine does against the Covid-19 virus mutations. But more information is needed. Both companies are also working on a "booster" shot to help the response to the mutations as well.
Even with unknowns, don't put off getting either shot. "The currently available vaccines are comparable, safe, and highly effective," Dr. Rimoin says.
Does either vaccine have side effects?
Both clinical trials found the most common side effects to be non-serious. They include pain where the shot was given, as well as fever, chills, fatigue, and headache, which indicate your immune system is ramping up. Both vaccines had very rare severe adverse effects. "Pfizer and Moderna vaccines are comparable in safety and side effects," Dr. Rimoin says.
The Centers for Disease Control and Prevention (CDC) has noted some cases of a severe allergic reaction called anaphylaxis among those who've been vaccinated. But these were also very rare for both vaccines: 2.5 cases per million doses for the Moderna vaccine during the period of December 21, 2020 to January 10, 2021. And 11.1 cases per million doses for the Pfizer vaccine during the period of December 14 to December 23, 2020, according to the CDC.
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Are allergic reactions common?
When you receive either vaccine you will likely be monitored shortly afterward for allergic reactions. In the CDC's reports, most occurred within 15 minutes of getting the shot. In the rare event you have a reaction, you'll be advised not to get the second shot. People allergic to any of the ingredients in the Pfizer or Moderna vaccine shouldn't get the shot, says the CDC (but neither vaccine contains eggs, preservatives, or latex).
If you have had allergic reactions to food or environmental triggers like pet dander, you should still get the shot. However, if you've had an allergic reaction to another vaccine, ask your doctor first.
"It is common to see adverse vaccine reactions once wider distribution to the general public begins, even if none of these reactions were observed in clinical trials," the Asthma and Allergy Foundation of America's Medical Scientific Council noted in a press statement. "Additional vaccines are in the pipeline so there will likely be more options if it is determined that one vaccine works better in certain populations than others. It's important to let the science do its work, not the headlines. Anyone with concerns about allergy risk should consult with their doctor."
(Here are the things allergists won’t tell you.)
What Are the Differences Between the Pfizer and Moderna COVID-19 Vaccines? Here’s What We Know So Far
NBC News’ speaks to frontline doctors nine months after the beginning of the pandemic to see how they’ve handled their fight against the virus.
How do the vaccines work?
The Moderna and Pfizer vaccines use the same technology, called "messenger RNA" or mRNA. "Both vaccines provide our cells with a building block for generation of the release of viral proteins [the Covid 'spike' protein] from our body," Dr. Panettieri says. "This released protein does not cause infection, but makes the body generate antibodies that fight infection."
Although the vaccine uses RNA to deliver info about the Covid protein so your cells can recognize the real thing, it doesn't affect your own genetic material (DNA). Although this is a new technology, mRNA vaccines have been in the works for a while. That's part of the reason why it was possible to develop them for Covid-19 so quickly.
(Here are other things doctors wish you knew about vaccines.)
Storage, transportation, and shelf life
Moderna's vaccine requirements make it a little bit easier to store than Pfizer's. The Moderna vaccine is transported at minus-4 degrees Fahrenheit, around the same temperature as a regular freezer. Pfizer's has to be shipped and stored at minus 94 degrees Fahrenheit, which requires special freezers most pharmacies and doctors' offices don't have.
Moderna also has a better shelf life: It's good in the fridge for 30 days (or room temperature for 12 hours). Pfizer's must be used within five days after thawing. One additional boon for Moderna: The minimum order is 100. Pfizer's is 975, but some communities don't actually need that much vaccine, so they may opt for Moderna.
But, these differences don't really affect anybody getting the shot. "For the participant receiving the vaccine, it is of no issue," Dr. Panettieri says. "Pfizer requires sophisticated storage requirements. But that should have zero concern for the participant receiving the vaccine. It's a logistics issue for the pharmacies or distributors."
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What ages are the vaccines for?
This is really the only difference when it comes to who should receive one vaccine over the other. "The Pfizer emergency use authorization is for people aged 16 and older," Dr. Rimoin says. "Moderna's is for people 18 and older, though the company has recently begun testing its vaccine in 12- to 17-year-olds."
(Learn how this new Covid-19 disease strikes children.)
What other vaccines are coming, and how do they compare?
“There are hundreds of other Covid-19 vaccines under development—including many with new mechanisms of action—that could prove to be effective, and cheaper and easier to distribute,” Dr. Rimoin says. Johnson & Johnson is submitting its application for Emergency Use Authorization for its vaccine, which the company says is 72 percent effective in the United States (66 percent globally).
“If it shows good safety and efficacy data, this vaccine is going to be a game-changer,” adds Dr. Rimoin. “It is a single dose and does not require extreme cold temperatures for storage like the Pfizer and Moderna vaccines.” Instead, the Johnson & Johnson vaccine can be stored in the fridge for three months, and the fact that it only requires one shot greatly simplifies the process.
How does the Johnson & Johnson vaccine work?
The Johnson & Johnson vaccine works a bit differently than the mRNA vaccines: It uses an adenovirus, a cold virus modified so it can’t make you sick, to transmit info about the Covid “spike” protein to your body, which then recognizes the protein as an invader and fights it. This is similar to the technology being used by the AstraZeneca/Oxford vaccine, which was recently approved in Europe.
Why would I want a vaccine that doesn’t work as well?
Although 72 percent sounds much less effective than the Pfizer and Moderna vaccines, the Johnson & Johnson vaccine is also 85 percent effective globally against severe Covid-19, the most dangerous aspect of the disease. Plus, its ease of use could speed up the process of getting everyone vaccinated.
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"If this were out there and we didn’t have the Moderna 94-95 percent [effectiveness] …we would have said, 'Wow, a 72 percent effective vaccine that’s even more effective against severe disease is really terrific,'" Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said in an interview with CNN. "But now we’re always judging it against 94 to 95 percent."
Optimal care always involves balancing known and potential benefits and risks, says epidemiologist Stanley H. Weiss, MD, a professor of epidemiology at Rutgers School of Public Health in New Brunswick, New Jersey. “Sometimes the enemy of good is ‘better,’ ” he says. "Should someone delay getting effective therapy while awaiting further improvements or access to something else? With SARS-CoV-2, becoming infected carries grave risks."
(Can Covid-19 harm your brain?)
So the benefit of getting any vaccine outweighs waiting for another?
Once the FDA approves the Johnson & Johnson vaccine for emergency use, “my recommendation is to get the vaccine that is made available to you, especially as there can be no assurance as to when or perhaps even if some other vaccine will become available,” Dr. Weiss says. For example, some places that don’t have the capabilities for the cold storage requirements of the other vaccines might be able to administer Johnson & Johnson’s vaccine, he says.
Plus, getting everyone vaccinated as soon as possible will help defeat the virus quicker. “To get the Covid-19 pandemic into check, we need as many people to get vaccinated with effective vaccines as soon as possible,” Dr. Weiss says. “The more rapidly the virus is spreading, the greater the number of viruses. And then the greater the chance that some new variant will arise. This again points to people not delaying."
It’s also possible a second “booster” shot could be added to the Johnson & Johnson vaccine. The company has "a second trial in progress examining efficacy of a two-dose schedule,” Dr. Weiss says. “We will need those results. But I do not recommend waiting for that data before getting an initial dose."
If you have a complex medical history, you can always talk to your doctor about your concerns over which vaccine to get. In general, though, “you should take an approved vaccine if you have the opportunity,” Dr. Weiss says.
The bottom line
Take whatever vaccine you can get first, as they all protect against getting a severe, potentially deadly case of Covid-19. “Any of these vaccines, including Johnson & Johnson’s, are better than current flu vaccines against the flu," which are 40 to 60 percent effective, says Dr. Panettieri. “Any Covid-19 vaccine will likely diminish Covid-19 health consequences compared with no vaccine.”
Next, here’s how to prep for a coronavirus winter.
When you hear the word "addiction," you may think of the negative consequences and changes in behavior that can come from gambling or the abuse of substances such as drugs and alcohol. It's not the same as dependence, which is when the body adapts to a substance and needs more to get the same effect.
The two often go hand-in-hand when it comes to drugs and alcohol, but dependence can exist without addiction. (Think caffeine withdrawal headaches when you skip your cup of Joe.) Although the Diagnostic and Statistical Manual of Mental Disorders (DSM), the 'bible' of psychiatry, doesn't consider all of the following as diagnosable mental health conditions, some are psychological addictions that may trigger unhealthy obsessions or behavior. (Although some are harmless.) Others are substances that can cause physical dependency.
Here are the surprising sensations, habits, and chemical changes that happen when using certain products or engaging in certain behaviors
If you've ever sat with a friend and watched as they applied and then reapplied Chapstick or any other lip balm repeatedly, there's a scientific reason for it, according to Samantha Conrad, MD, a dermatologist at Northwestern Memorial HealthCare in Chicago. The ingredients in some products can end up being extremely drying, which prompts you to feel the need to keep reapplying it.
"In addition, the feeling of being 'addicted to Chapstick' is that the person has become very used to a textural feeling on his or her lips," she says. "When they don't have the product on, they feel that something is missing." (Curious? Find out what really causes chapped lips.)
It's one thing to use whitening strips regularly to remove red wine and coffee stains. It's quite another to be addicted to bleaching your teeth. There's even a term for it: Bleachorexia refers to being addicted to bleaching teeth, says Leslie Renee Townsend, DDS, of Jefferson Dental and Orthodontics in Dallas. "Overuse or misuse of whitening products such as lasers, strips, gels, rinses, or pastes can cause noticeable sensitivity, tooth pain, gum irritation, and weakened enamel, often temporary, but sometimes more permanent," Dr. Townsend says. "At worst, teeth begin to demineralize with time, since whitening products strip tooth enamel resulting in transparent-looking teeth."
If you tend to moisturize more than twice a day, you may want to cut back. Turns out, what you're doing may be counterintuitive and make your skin "addicted" to that product. "There are some theories that constant use of thick moisturizers can make the skin lazy," says Joshua Zeichner, MD, director of cosmetic and clinical research in the department of dermatology at Mount Sinai Hospital in New York City. "By providing a false barrier to the environment, the skin does not have to work as hard as it normally would to maintain adequate hydration levels. If you were to quickly take away the moisturizer, your skin might end up dry and inflamed."
In fact, it's a myth that everyone needs to use a moisturizer. "If you have skin conditions like eczema or if you experience dryness, visible scaling or flaking, redness, or itching, a moisturizer can help," he adds. "However, if your skin looks and feels normal, you do not necessarily need to use a moisturizer regularly." If you want to use a moisturizer, opt for a breathable product that's light and easy to spread. "The newest generation of moisturizers use technology that allows you to experience the benefits of traditional ingredients without a greasy, heavy feeling," Dr. Zeichner adds.
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Exercise
"Exercise addicts tend to feel that exercise is the most important thing in their life," says Rachel Straub, an exercise physiologist in San Diego. "They also use exercise as a coping strategy to control emotions." How you know you're an exercise fanatic: "To check in with yourself, consider if you have to continually increase exercising to feel satisfied, or if you experience irritability or depression when you suddenly reduce the exercise you're getting," Straub says. Need help? Watch out for these 9 signs you're probably exercising too much.
Plastic surgery can quickly become an addiction for some. "Patients seeking Botox often start out wanting to look 'natural,'" says John Layke, MD, a plastic surgeon at Beverly Hills Plastic Surgery Group. "But once they see how Botox smooths out fine lines and relaxes deep furrows, they notice small lines when they make expressions, and they want those gone too. Pretty soon, if the physician lets them, the 'natural' look becomes frozen." Often people can get hooked on facial fillers, especially in the lips and cheeks, and liposuction, adds Dr. Layke. "Procedural 'addicts' are usually unaware of their addiction and most often need to be turned away by their plastic surgeon," he says. "This type of patient literally skips from office to office until someone agrees to give them what they want. It is usually the surgeon or injector who makes the diagnosis of 'addiction.'"
If your allergies prompt chronic red eyes and you routinely reach for over-the-counter eye drops like Visine, you could begin to rely on them. These drops work because of active ingredients such as tetrahydrozoline, a vasoconstrictor that constricts the conjunctival blood vessels so that they appear smaller, making your eyes look less red. "Some patients may find themselves increasing their frequency of use because Visine also has a known rebound effect," says Kelly Voltz, an optometrist in Portland, Oregon. "For some percent of the population, extended use of Visine can cause redness, and patients may find themselves in a cycle of using a product which initially helped the problem but now contributes to it." (Avoid drops by learning the causes of bloodshot eyes and how to prevent them.)
"Addiction is psychosomatic," says Kirby Farrell, PhD, a professor at the University of Massachusetts at Amherst, who has written frequently about the topic. "How you think about yourself affects your body. If you imagine that tattoos can change people's perception of you, you can believe that a new image on your skin will impress others, boost your self-esteem, and eliminate the need for more needlework." At the same time, new ink may not be enough. "In searching for more images, you may be going around in circles, depressed or angry at yourself and not seeing a new, happier face in the mirror. That can feel—and trap you—like an abused substance."
If you're perpetually in need of retail therapy, take note. It turns out there are as many reasons to become addicted to shopping as there are shopping addicts, says April Lane Benson, PhD, author To Buy or Not to Buy: Why We Overshop and How to Stop. "Some of the motivators include wanting to feel better about yourself or to feel more secure," she says. "Shopping can also be a way to soothe oneself, to feel more in control, or to fill an internal void." How do you know if you're an addict? "You can be pretty sure you are if shopping is your equal opportunity all-purpose mood changer, if you've tried to stop and have been unable to, if you're hiding purchases or bills, and/or if you're lying about this to yourself and to others," Benson says.
Thanks to social media algorithms that can see exactly how you're interacting with social media posts, you can be addicted to finding the perfect chairs, potted plants, or woven rug to pull a room together to then post online, says Lindsey Pratt, a therapist in private practice in New York City who specializes in addiction and recovery. "Targeted ads play off this addiction, and it's now easier than ever to curate an experience at home to sell to the world rather than living in reality," she adds. Online shopping can be convenient, but sometimes you need to see furniture in person to make sure it's worth the investment and realistic for your lifestyle.
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Listening to music
This is one addiction you won't need to kick. A study published in Scientific Reports found that listening to enjoyable music creates a natural high. "The body reacts in the same way as when it eats pleasurable food, by releasing the neurotransmitter dopamine," says Duy Nguyen, DO, a board-certified psychiatrist at Beachway Therapy Center in Boynton Beach, Florida. "It is this chemical that makes us want to repeat behaviors to regain that feeling again, which is why we can become addicted to listening to our favorite songs."
Tanning addiction is very common, particularly among young men and women between the ages of 18 and 30. In fact, a study conducted by the Georgetown University Medical Center concluded that 1 in 5 young white women who have used a tanning bed in the last year showed signs of dependence, says dermatologist Deborah S. Sarnoff, MD, president of The Skin Cancer Foundation. Just how bad is tanning? More than 450,000 cases of skin cancer in the United States, Europe, and Australia each year are linked to indoor tanning, per 2017 research published in JAMA Dermatology. How do you know if you're addicted? "There are a few telling signs," Dr. Sarnoff says. "UV light has been shown to trigger a release of endorphins, the feel-good hormone," she says. "You might find yourself craving that feeling of happiness. If you find you're going to the tanning salon more often or staying in the tanning bed longer, that could be a sign of dependence."
If it's as easy to find a date as it is to swipe left or right, it's simple to see how online dating could be addictive. "People are addicted to online dating because so many of us have deep-rooted fantasies of finding Mr. or Ms. right who will change, rescue, or drastically improve our lives," says Isabel James, a matchmaker and relationship coach at Elite Dating Managers, where many clients report checking for potential matches more than 20 times a day. "We like to believe one person can do this, and the media has lead us to believe so as well. Being in love can be one of the greatest things in life, and dating app addictions trail this desire."
The clinical term for this is trichotillomania, and it's when someone can't stop twisting or pulling their hair out, says Anna Guanche, MD, a board-certified dermatologist and founder of the Bella Skin Institute in Calabasas, California. It's not just the hair on your head. Dr. Guanche says some people will pull the hair on their eyebrows or even eyelashes as a compulsive urge or mindless habit, such as when they are watching TV. (Check out these 18 other habits that cause your hair to thin.)
Diet soda can affect your metabolism, and is associated with numerous health problems from type 2 diabetes to high blood pressure. But giving it up can be more complicated than you might think. While the addiction may stem from the artificial sugars in diet soda Sheri Heller, a licensed clinical social worker and addiction specialist based in New York, says the addiction also can stem from weight control and body dysmorphia. "I've worked with [clients] who drink liters of diet soda and can't seem to stop, even when they incur physical maladies," she says.
This is a fairly common addiction, according to Heller. While similar to shopping, the focus here is on specific objects that help conceal feelings of inferiority by creating an elite persona. In the case of shoes, it sometimes can be linked to a foot fetish, Heller says, but more often than not, excessive shoe buying is done to fill some other kind of inner void.
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Television
Binge-watching an occasional show is one thing, but if you find yourself parked in front of the TV all the time, it could be a sign of a bigger issue. "Nielsen Media Research found that the average American watches four to five hours of television each day," says Dr. Nguyen. "By the time they reach 65 years old, that would mean they would have spent an astonishing nine years watching television." Not only can revolving your life around what's on television cause distorted reality and other behavioral issues, but it also promotes a sedentary lifestyle, setting you up for developing health conditions such as cardiovascular and heart disease, says Dr. Nguyen. (Put down that remote. Here are 17 strategies to help beat your TV addiction.)
Posting selfies on social media and incessantly refreshing your feed for new comments and likes all result in a dopamine hit to your system, Pratt says. A social competition to see who looks like they are living the best life feeds the addiction to continue the behavior, she adds.
Whether you enjoy having sex (and therefore feel like you need to have a lot of it) or can't stop looking at porn, Dr. Nguyen says you may have a hypersexual disorder. And while having sex can be good for you, this particular disorder negatively affects your relationships and how you function at work, home, and all other areas of your life. It also means your brain is hardwired similar to someone who has a gambling or drug addiction, Dr. Nguyen says, making it difficult to give up that behavior.
Those who enjoy extreme sports such as rock climbing, snowboarding, and mountain biking are often labeled as "adrenaline junkies" because they are addicted to the thrill and feeling of euphoria they get from those activities, Dr. Nguyen says. A study published in the Journal of Behavioral Addictions found that when people don't participate in those sports over an extended period, they appear to experience symptoms of withdrawal consistent with addictive behaviors.
Constantly being busy has started to become culturally acceptable in the US, particularly in cities and anywhere where there is a level of peer competition, says Pratt. "Being busy can fill the void that is felt when being alone and truly experiencing what it is like to spend time with oneself, [which] is often avoided at a level of addiction," she says. This notion of feeling like you always have to be busy can often start in the workplace.
Saying "I'm sorry" for no reason at all or during a situation that's completely out of your control can be an addiction, says Cindy Shaw, a certified neurolinguistic practitioner, and transformational life and brain health coach. "Unnecessary apologizing is a habit that self-awareness, brain training, and mindfulness can easily aid over time," Shaw says.
From scrutinizing your weight to anticipating the worst outcome of a situation, negative self-talk can quickly become ingrained in a person's brain from a young age. "For many people, negative self-talk has been so pervasive throughout their lives that it's just become a habit [similar to an addiction]," Shaw says. "Intentionally monitoring your inner dialogue and replacing overly harsh thoughts with more neutral or positive sentiments will help you break the habit once and for all."
Similar to how online dating can lead to never-ending possibilities of finding your soulmate, the romantic feelings of love can be addicting, according to a study published in the journal Philosophy, Psychiatry, & Psychology. Researchers discovered behavioral, psychological, and neurophysiological evidence that feelings of love have similar effects to chronic, drug-seeking behavior, and coming down off of these behaviors (like going through a breakup) can lead to feelings of withdrawal.
The act of winning is addictive in itself, and when you combine that with a virtual world that is completely different and more exciting than your real life, that environment can become addicting, says Dr. Nguyen. Some signs of a video game addiction include becoming irritable when not playing over an extended period of time, and needing more and more screen time to feel satisfied and content. This relatively new condition has been named "gaming disorder" by the World Health Organization.
Called pagophagia, chewing ice is considered a form of pica, a type of eating disorder in which someone feels the need to chew items that have no nutritional value. Ice cravings may be specific to an iron deficiency, as well as a red flag for obsessive-compulsive disorder or another developmental issue.
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Moderna and Pfizer have COVID-19 vaccines that are safe and effective, based on testing in tens of thousands of people. But there are differences.The Food and Drug Administration granted emergency use authorization for Pfizer's two-shot vaccine last week, and agency regulators are expected to greenlight Moderna's very similar two-dose mRNA shot course later this week. An FDA expert panel will meet Thursday to discuss and vote on Moderna's shot, teeing up an agency decision that could come as soon as Friday. 
Moderna's coronavirus vaccine is similar to the Pfizer-BioNTech vaccine that was authorized and shipped out to Americans earlier this week. But there are a few key differences. Most importantly, Moderna's vaccine can be stored in normal freezers and does not require a super-cold transportation network, making it more accessible for smaller facilities and local communities. The US Food and Drug Administration's vaccine advisory committee meets Thursday to review whether to recommend emergency use authorization for Moderna's vaccine, with the FDA's decision expected by Friday. 
What the Moderna and Pfizer/BioNTech vaccines may feel like.On Thursday, a committee that advises the Food and Drug Administration will meet to determine whether the Moderna vaccine should get an emergency use authorization. Ahead of the decision, the agency shared the most comprehensive data to date on what we know about the shot. The same process happened last week with the Pfizer/BioNTech vaccine, which is now being rolled out across America following an EUA Friday night. 
More than a dozen frontrunners have reached late-stage clinical trials.Many of the other candidates, however, will fail somewhere along the vaccine development pipeline, which includes three rounds of clinical trials with increasingly large pools of volunteers to assess their safety, efficacy, and ability to prompt a response from the immune system. And for those that achieve authorization, there remain important questions that we’ll need more time and further research to answer, including how long the immunity they offer from COVID-19 lasts. 
We asked three dietitians for their top picks of the healthiest fast food chicken nuggets for your next stop at your favorite fast-food spot. 
NBC News’ speaks to frontline doctors nine months after the beginning of the pandemic to see how they’ve handled their fight against the virus. 
Even with a COVID-19 vaccine available, experts are still learning about the virus itself and the potential long road to recovery. NBC’s Erin McLaughlin talks to some patients as they open up about the symptoms they’re still experiencing. 
The illness has affected nearly every aspect of life. 
