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This has been updated as of March 1, 2021.

COVID-19 Coronavirus Vaccine

The rapid pace of COVID-19 vaccine news is hard enough for the general population to keep up with. But if you are immunocompromised or have an autoimmune condition, it’s even tougher to tell what the evolving headlines mean for you.

Could the vaccine’s effectiveness be dampened by immunosuppressant medications, such as disease-modifying antirheumatic drugs (DMARDs) and biologics? Have clinical trials included people with rheumatic or autoimmune conditions? How will people with these chronic illnesses be prioritized?

This article will explore these issues and help educate you about deciding to get a COVID-19 vaccine as someone who has an autoimmune condition, is immunocompromised, or takes immunosuppressant medication.

Should You Get a COVID-19 Vaccine If You’re Immunocompromised or Have an Autoimmune Condition?

The answer is generally yes. The U.S. Centers for Disease Control and Prevention has said that people with weakened immune systems or autoimmune conditions can get a COVID-19 vaccine. Guidance from medical organizations that oversee the care of people with autoimmune conditions, including the American College of Rheumatology and the American College of Asthma, Allergy, and Immunology recommend the COVID-19 vaccine for most patients.

The decision to get a COVID-19 vaccine, including whether you need to make any adjustments to your immunosuppressant medications after you get the vaccine, is something you need to discuss with your doctor.

But experts want patients to know that the benefits of getting the vaccine for most people who are immunocompromised or have autoimmune conditions far outweigh any risks or question marks.

“We want patients to get a COVID-19 vaccine — hard stop,” says rheumatologist Jeffrey Curtis, MD, MPH, a Professor of Medicine at the University of Alabama at Birmingham who led the task force that created the ACR COVID-19 vaccine guidance.

Where We Stand Now

What is the current status of coronavirus vaccine development? Around the world, there are almost 70 different vaccines in clinical trials on humans and nearly another 90 in pre-clinical phases (being studied in the lab or in animals).

There are a number of leading candidates in various stages of testing, review, and deployment, and they work in different ways. The U.S. front-runners currently making the most headlines are from the following pharmaceutical companies:

  • Pfizer and its partner BioNTech
  • Moderna
  • AstraZeneca in collaboration with the University of Oxford
  • Johnson & Johnson
  • Novavax

The Pfizer BioNTech, Moderna, and Johnson & Johnson vaccines have received emergency use authorization from the U.S. Federal Drug Administration (FDA).

How Vaccines Traditionally Work

When many of us think of vaccines, we think of an injection that contains a live germ that has been weakened (“attenuated”) in order to trigger a controlled immune system response that “trains” the body to fight that germ if encountered in the future. This approach was used to develop vaccines against conditions such as measles, mumps, and rubella.

Live vaccines offer strong protection against disease, but they may not be recommended for people who are immunocompromised because there’s a chance such vaccines could kick off a risky immune response.

Another approach to immunization involves “inactivated” vaccines, in which a “killed” germ is used to teach the body to build immunity. The flu and polio shots, as well as the rabies vaccine, are inactivated. These kinds of vaccines offer less protection (thus requiring boosters), and are therefore thought to be safer for people who are immunocompromised.

The New Technology Behind the COVID-19 Vaccines

The COVID-19 pandemic has forced scientists into new scientific territory:

mRNA Vaccines

Their approach makes use of messenger RNA (mRNA), which carries instructions from the coronavirus’s genetic code that show your cells how to manufacture the coronavirus “spike” protein (those protrusions dotting the coronavirus). This teaches your body to recognize the spike protein on coronavirus germs as foreign and mount an immune system response.

Because mRNA are delicate, this vaccine is encased in a lipid particle envelope to transport the mRNA inside human cells.

The Pfizer and Moderna “envelopes” are made differently from each other, which is why the Pfizer vaccine would need to be stored at approximately -100 degrees F (presenting distribution challenges) and the Moderna vaccine can be kept for a time in a standard refrigerator.

Both vaccines require two doses about three weeks (Pfizer) to a month (Moderna) apart.

Viral vector vaccines

At the same time, AstraZeneca and Johnson & Johnson have been testing a different kind of vaccine called a viral vector vaccine. This uses the virus that causes the common cold (called adenovirus) to get the coronavirus genetic material into cells, where it teaches the body to recognize the coronavirus spike protein. The adenovirus is genetically modified so it cannot replicate and cause disease.

The AstraZeneca vaccine requires two doses. Johnson & Johnson is studying a two-dose and a single-dose version. The one-dose version is authorized by the FDA and results from the two-dose trial will be available later this spring.

Which COVID-19 Vaccines Are Approved?

On December 11, 2020, the U.S. Food and Drug Administration (FDA) granted emergency use authorization (EUA) to the Pfizer vaccine based on the data from its phase 3 clinical trial, which has been shown to achieve 95 percent efficacy. A week later on December 18, 2020, the Moderna vaccine, which has 94 percent efficacy, received emergency use authorization. The Johnson & Johnson vaccine was authorized on February 27, 2021. Efficacy varied by geography, but overall it reduced moderate to severe cases of COVID-19 by 66 percent. (In the U.S., it reduced moderate to severe/critical cases by 72 percent and severe/critical cases by 86 percent).

It’s important not to get too hung up on comparing clinical trial results between the Johnson & Johnson and other vaccines, because it would be like comparing apples to oranges. The trials were conducted at different times during the pandemic. The Johnson & Johnson trial had to contend with new coronavirus variants that the Pfizer and Moderna vaccine trials did not.

EUA is not official FDA approval, but would allow the vaccine to be used because there’s a life-threatening emergency and the safety and efficacy data show benefits that outweigh potential risks.

AstraZeneca is completing phase 3 clinical trials in the United States and is currently being used in other countries.

Were Immunocompromised People Included in COVID-19 Vaccine Clinical Trials?

When it comes to any new vaccine, people living with inflammatory or autoimmune conditions — such as inflammatory rheumatic diseases (rheumatoid arthritis, axial spondyloarthritis, lupus); inflammatory bowel disease (Crohn’s disease and ulcerative colitis); psoriasis; and multiple sclerosis — have long had vaccine worries that the general public doesn’t. There are two general main concerns:

  • That a vaccine might unsafely activate their immune system
  • That immunosuppressant medications might reduce the vaccine’s effectiveness

In the case of the COVID-19 vaccines, there is not a lot that can be definitively said about how people with such medical conditions might react because they were not included in the clinical trials.

This is not unique to COVID-19 vaccines. It’s common for vaccine trials to start by only studying healthy people without medical conditions or medications that could affect the results.

However, just because people on immunosuppressant medication were not included in the clinical trials does not mean the vaccines are unsafe for them. This is a common misperception.

The American College of Rheumatology vaccine guidance addresses this: “There is no direct evidence about mRNA COVID-19 vaccine safety and efficacy in [rheumatic and musculoskeletal disease patients]. Regardless, there is no reason to expect vaccine harms will trump expected COVID-19 vaccine benefits.”

Examples of Clinical Trial Exclusion Criteria

Clinical trials for vaccines include a protocol that details who can participate (inclusion criteria) and who cannot participate (exclusion criteria).

A review of the exclusion criteria for the Pfizer vaccine’s clinical trials says it barred “immunocompromised individuals with known or suspected immunodeficiency” as well as “individuals who receive treatment with immunosuppressive therapy,” and even people who were “anticipating the need for immunosuppressive treatment within the next six months.”

As for the Moderna vaccine, clinical trials excluded participants with an “immunosuppressive or immunodeficient state,” as well as those who have “received systemic immunosuppressants or immune-modifying drugs for >14 days in total within six months prior to screening.”

Johnson & Johnson’s trial allowed people with certain underlying medical conditions to participate in if their signs and symptoms are stable and well-controlled. “Participants with clinical conditions stable under non-immunomodulator treatment (e.g., autoimmune thyroiditis, autoimmune inflammatory rheumatic disease such as rheumatoid arthritis) may be enrolled at the discretion of the investigator. Non-immunomodulator treatment is allowed as well as steroids at a non-immunosuppressive dose or route of administration.” However, people on immunosuppressant medications would likely be excluded.

In the AstraZeneca trials, with narrow exceptions, volunteers in “any confirmed or suspected immunosuppressive or immunodeficient state” were not allowed to participate.

So How Do We Get Vaccine Data on Immunocompromised People?

It’s important to know that just because these patient populations were not included in the initial clinical trials does not mean patients can’t get the vaccine.

People with autoimmune and inflammatory diseases and those on immunosuppressive therapies will be evaluated after the vaccines are on the market, which is common practice.

“Typically, patients are studied in phase 4 trials, or post-marketing surveillance, when a drug has been FDA approved,” says Mario Castro, MD, Vice Chair for Clinical and Translational Research in the Department of Internal Medicine and a pulmonologist at the University of Kansas School of Medicine, via email. With the information from phase 3 studies, he adds, scientists know what the expected efficacy and safety of a vaccine is so when they can begin studying “more difficult patient populations” they have some idea of what to anticipate.

Remember that providers and patients dealing with rheumatologic and autoimmune conditions have navigated this same data blind spot every time a new vaccine comes out.

“This is very, very typical,” says Leonard Calabrese, DO, head of the Cleveland Clinic’s Section of Clinical Immunology. “If you take the most recent vaccine for shingles, there were 36,000 patients in the clinical trial, but there were only a few score of patients with autoimmune disease, and none of them were on significant immune suppression. So now it’s several years later and we’re just figuring it out.”

Researchers are starting to study people with autoimmune conditions and those taking immunosuppressant medication after they get a COVID-19 vaccine to check for things like effectiveness and side effects, and whether they’re different from that of the general population. Read more here about this research and what we might learn from it.

Vaccine Safety and Efficacy for Immunocompromised Patients

Even in the absence of specific data, experts in rheumatologic and autoimmune diseases have enough clinical experience to make recommendations on a number of issues. Here are answers to common concerns.

Could COVID-19 Vaccines Activate the Immune System in an Unsafe Way?

The current COVID-19 vaccine candidates are not considered “live,” which reduces concerns about their safety in immunocompromised people.

The ACR guidance says, “beyond known allergies to vaccine components, there are no known additional contraindications to COVID-19 vaccination.” This means that simply having an autoimmune or inflammatory rheumatic disease — or taking immunomodulating medication to treat it — is not a reason to not get a COVID-19 vaccine.

“We have no reason to believe these vaccines will be any less safe in an immune-mediated inflammatory disease population,” says Dr. Calabrese. “These are not live vaccines, and there’s no reasonable concern that our patients will have higher risks. But as with anything, it deserves careful study.”

“If you’re taking immunosuppressant biologics, say, for arthritis, live attenuated vaccines are not recommended,” says Vinicius Domingues, MD, a rheumatologist in Daytona Beach, Florida, explaining that a dose of a live virus that would not trigger disease in healthy patients could trigger disease in someone who is immunosuppressed. “But these new COVID-19 vaccines don’t carry live viruses. They can’t trigger disease, which is great for this patient population.”

While it’s helpful to hear that the mRNA and viral vector COVID-19 vaccine candidates are safer for immunosuppressed patients than live vaccines, it’s reasonable to wonder how the safety profiles of the mRNA and viral vector mechanisms compare to each other.

Based on these two vaccine mechanisms, we have no reason to believe there’s a difference in safety between them for immunocompromised patients, says Nilanjana Bose, MD, a board-certified rheumatologist with the Rheumatology Center of Houston. But she adds that we don’t yet have the data to know for sure.

Is This Super-Fast Vaccine Development Safe?

Another concern is the lightning-fast development of the COVID-19 vaccines, which has left even people who don’t have chronic conditions worrying if corners are being cut.

“Obviously this is a compressed timeline, but we have had very strong processes in place for a long time that determine how we review evidence,” says Grace Lee, MD, Professor of Pediatrics at Stanford University School of Medicine and Associate Chief Medical Officer for Practice Innovation at Stanford Children’s Health. “All the steps of our routine decision-making process for every vaccine will be the same for these vaccines. It’s just that we’re having many more meetings on a much tighter timeline.”

Dr. Lee is a member of the U.S. Advisory Committee on Immunization Practices (ACIP), which is a group within the U.S. Centers for Disease Control and Prevention (CDC) that makes recommendations on the use of vaccines. She is a member of the ACIP’s COVID-19 Vaccines Workgroup and Chair of the COVID-19 Vaccine Safety Technical Subgroup.

In addition, she says, the CDC has set up extra surveillance for COVID-19 vaccines. So multiple systems will be in place in order to have all eyes on safety as approval and rollout occurs.

Do the Vaccines Work as Well in Immunocompromised Patients?

Based on what experts know about how patients respond to other kinds of vaccines (such as the flu or shingles vaccine), there’s good reason to think that COVID-19 vaccines will not work as well in people who take medication that affects immune system function.

People who are on immunosuppressant medication tend to mount a less strong response to vaccines generally, noted Kevin Winthrop, MD, MPH, Professor of Infectious Diseases, Ophthalmology and Professor of Public Health and Preventive Medicine at Oregon Health & Science University in Portland, during a Facebook Live discussion with the Spondylitis Association of America.

Dr. Domingues explains why: “For you to have a good response to a vaccine that achieves protection from disease, your body needs to be able to mount a strong immune response in general. But for patients who are on immunosuppressant medications, their response is weakened.”

This is true for all vaccines, not just for the COVID-19 candidates, he points out. One well-known example is patients taking methotrexate or biologic drugs who are due for a flu vaccine. “The efficacy can be lower for people on these medications because their immune response is weaker overall,” Dr. Domingues adds.

However, that doesn’t mean that the COVID-19 vaccine doesn’t work — it may just work less well than in people who don’t take these medications. But even a slightly less effective vaccine may still help prevent severe disease that requires hospitalization (or worse).

Think of it this way: If you had a choice between being in a snowstorm wearing a winter coat, hat, gloves, and scarf (fully effective vaccine) versus a just a winter coat (less effective vaccine) versus just a T-shirt (no vaccine), of course you’d prefer having all the winter attire. But having the coat is way better than just the T-shirt.

Should You Stop Taking Immunosuppressant Medications After Getting a COVID-19 Vaccine to Help Increase Its Effectiveness?

Because immunosuppressant medications decrease the immune system’s response to a vaccine, temporarily stopping certain medications after you get a vaccine or OR trying to time when you get the vaccine so it occurs at a certain point during the course of your treatment may help make the vaccine more effective.

While there’s no data on this from COVID-19 vaccines directly, experts are making some recommendations based on indirect evidence from what is known from other kinds of vaccines and how the immune system works generally.

The ACR guidance addresses this in more detail, and you can read more about which medications they suggest pausing vs. continuing here. But this advice needs to be individualized for everyone. Your doctor may have a different recommendation for your situation.

Also, keep in mind that different medications work in different ways, so just because it’s suggested that one medication be temporarily paused after getting the COVID-19 vaccine — say, methotrexate — doesn’t mean that your biologic should necessarily be stopped too.

Two medications that patients have a lot of questions about are methotrexate and rituximab. We have separate resources on these medications here:

What About Vaccine Side Effects If You’re Immunocompromised?

Another common worry involves the side effects that are expected from the COVID-19 vaccines. Mild side effects from vaccines are common and to be expected. They’re a sign that your body is revving an immune response. Common side effects from the first COVID-19 vaccines include:

  • Pain and stiffness at the injection site
  • Fatigue
  • Headache
  • Muscle aches
  • Joint stiffness

Dr. Bose is advising patients to be prepared for possible discomforts including fever and body aches, which she says “seem more pronounced than with other vaccines.”

For his part, Dr. Domingues says the immediate side effects “seem to be quite reasonable and safe,” but points out there is not yet any data on the possibility of long-term side effects. However, considering the known risks of COVID-19 infection, his recommendation is clear: “Overall we still believe the risk benefit analysis is in favor of vaccination by far.”

What About Allergic Reactions to the COVID-19 Vaccine?

Allergic reactions have been a concern for the mRNA COVID-19 vaccines from Pfizer and Moderna, but as of now the only people who should not get a COVID-19 vaccine because of allergy-related concerns is very narrow. It includes you if:

  • You’ve had a severe allergic reaction (anaphylaxis) after a previous dose of an mRNA COVID-19 vaccine or any of its components
  • You’ve had an immediate allergic reaction of any severity to a previous dose of an mRNA COVID-19 vaccine or any of its components (including polyethylene glycol [PEG])*
  • You’ve had an immediate allergic reaction of any severity to polysorbate (due to potential cross-reactive hypersensitivity with the vaccine ingredient PEG)*

* The CDC says these groups should not receive an mRNA COVID-19 vaccine at this time unless they have been evaluated by an allergist-immunologist and it is determined that the person can safely receive the vaccine (such as under observation, in a setting with advanced medical care available).

Read more here about what to know if you have concerns about having a history of allergies:

How Are People with Chronic Conditions Being Prioritized for the Vaccine?

The CDC has been promoting a phased approach to the vaccine rollout, with health care workers and people living and working in long-term care facilities prioritized first, then extending eligibility to older adults and essential workers, and then to people with chronic health conditions. However, it is up to individual states to decide who is eligible to get a vaccine in that state and when.

In some states, people with high-risk medical conditions are currently eligible to receive COVID-19 vaccines. This doesn’t necessarily include autoimmune conditions, but rather focuses on many conditions that are comorbidities for inflammatory and autoimmune patients, including: obesity, diabetes, COPD, heart conditions, chronic kidney disease, cancer, sickle cell disease, and those who have undergone solid organ transplantation.

This article from Verywell Health shows how you can sign up for a COVID-19 vaccine in every state.

In addition, the American College of Rheumatology says in its guidance that people with autoimmune and inflammatory arthritis should be prioritized for vaccination before the non- prioritized general population of similar age and sex.

The Bottom Line

First, know that doctors and public health experts strongly encourage most patients with autoimmune diseases and who take immunosuppressant medications to get vaccinated.

“I think it’s important for everyone to try to get vaccinated,” says Dr. Bose. “I would advise anyone who tells me they have concerns to get more informed. We are optimistic this will work.”

“I’m confident we’ll be engaging in shared decision-making with patients who can’t wait for perfect data,” says Dr. Calabrese.

Dr. Calabrese will help his own patients decide when to get the vaccine by factoring in the severity of their underlying disease as well as their risks for severe COVID-19, such as having high blood pressure, obesity, or kidney disease. He’ll also consider their concerns regarding COVID-19, which range from ‘I’m not worried because I’m hunkered down’ to ‘the pandemic is ruining my life.’

If you want to read about the experiences of patients with autoimmune and inflammatory diseases who got the COVID-19 vaccine, check out these patient stories:

In the meantime, just because vaccines are finally on the way doesn’t mean we can loosen up on the protective habits that we know help prevent COVID-19 transmission. Doctors are urging patients to continue wearing masks, maintaining social distancing, and washing hands.

“People with autoimmune conditions can have a reduced response to any threats to their immune system and they may be vulnerable to COVID-19 [complications], but also to flu and other infections,” says Bala Murugan, MD, Acting Chief Medical Officer at the Arkansas Department of Health and board member of the National Association of Chronic Disease Directors. “In a pandemic we expect that they follow the three Ws — wearing masks, watching distance, and washing hands — carefully more so than the general population because of the nature of their underlying immune conditions.”

Read more here about what to do after getting a COVID-19 vaccine and what to expect about getting the second dose of a COVID-19 vaccine.

Get Free Coronavirus Support for Chronic Illness Patients

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A Phase 1/2/3, Placebo-Controlled, Randomized, Observer-Blind, Dose-Finding Study to Evaluate the Safety, Tolerability, Immunogenicity, and Efficacy OF SARS-COV-2 RNA Vaccine Candidates Against COVID-19 in Healthy Individuals. Pfizer. https://pfe-pfizercom-d8-prod.s3.amazonaws.com/2020-09/C4591001_Clinical_Protocol.pdf.

 A Phase III Randomized, Double-blind, Placebo-controlled Multicenter Study in Adults to Determine the Safety, Efficacy, and Immunogenicity of AZD1222, a Non-replicating ChAdOx1 Vector Vaccine, for the Prevention of COVID-19. AstraZeneca. September 17, 2020. https://s3.amazonaws.com/ctr-med-7111/D8110C00001/52bec400-80f6-4c1b-8791-0483923d0867/c8070a4e-6a9d-46f9-8c32-cece903592b9/D8110C00001_CSP-v2.pdf.

A Phase 3, Randomized, Stratified, Observer-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1273 SARS-CoV-2 Vaccine in Adults Aged 18 Years and Older. Moderna TX, Inc. August 20, 2020.  https://www.modernatx.com/sites/default/files/mRNA-1273-P301-Protocol.pdf.

A Randomized, Double-blind, Placebo-controlled Phase 3 Study to Assess the Efficacy and Safety of Ad26.COV2.S for the Prevention of SARS-CoV-2-mediated COVID-19 in Adults Aged 18 Years and Older. Clinical Protocol. September 15, 2020. https://www.jnj.com/coronavirus/covid-19-phase-3-study-clinical-protocol.

Coronavirus Vaccine Tracker. New York Timeshttps://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html.

COVID-19 Vaccine Clinical Guidance Summary for Patients with Rheumatic and Musculoskeletal Disease. American College of Rheumatology. February 8, 2021. https://www.rheumatology.org/Portals/0/Files/COVID-19-Vaccine-Clinical-Guidance-Rheumatic-Diseases-Summary.pdf.

COVID-19 Vaccination Considerations for Persons with Underlying Medical Conditions. COVID-19. U.S. Centers for Disease Control and Prevention. December 29, 2020. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/underlying-conditions.html.

COVID-19 Vaccines & Spondyloarthritis. Facebook Live. Spondylitis Association of America. https://fb.watch/2hZD-oPpBH.

Different COVID-19 Vaccines. Coronavirus Disease 2019 (COVID-19). U.S. Centers for Disease Control and Prevention. November 24, 2020. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html.

Emergency Use Authorization for Emergency Use of Moderna COVID‐19 Vaccine for the Prevention of Coronavirus Disease 2019 (COVID-19) for Individuals 18 Years of Age and Older. U.S. Food & Drug Administration. December 18, 2020. https://www.fda.gov/media/144636/download.

Emergency Use Authorization for Emergency Use of Pfizer-BioNTech COVID‐19 Vaccine for the Prevention of Coronavirus Disease 2019 (COVID-19) for Individuals 16 Years of Age and Older. U.S. Food & Drug Administration. December 11, 2020. https://www.fda.gov/media/144412/download.

Hesselstrand R, et al. Immunogenicity and safety of pneumococcal vaccination in patients with systemic sclerosis. Rheumatology. April 2018. doi: https://doi.org/10.1093/rheumatology/kex471.

How CDC Is Making COVID-19 Vaccine Recommendations. COVID-19 (Coronavirus Disease). U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations-process.html.

Information from the American College of Rheumatology Regarding Vaccination Against SARS-CoV-2. American College of Rheumatology. September 9, 2020. https://www.rheumatology.org/Portals/0/Files/ACR-Information-Vaccination-Against-SARS-CoV-2.pdf.

Interview with Bala Murugan, MD, Acting Chief Medical Officer at the Arkansas Department of Health and board member of the National Association of Chronic Disease Directors

Interview with Grace Lee, MD, Professor of Pediatrics at Stanford University School of Medicine and Associate Chief Medical Officer for Practice Innovation at Stanford Children’s Health

Interview with Jeffrey Curtis, MD, MPH, a rheumatologist and Professor of Medicine at the University of Alabama at Birmingham

Interview with Leonard Calabrese, DO, head of the Cleveland Clinic’s Section of Clinical Immunology

Interview with Maria Danila, MD, a rheumatologist at the University of Alabama Birmingham

Interview with Mario Castro, MD, Vice Chair for Clinical and Translational Research in the Department of Internal Medicine and a pulmonologist at the University of Kansas School of Medicine

Interview with Nilanjana Bose, MD, a board-certified rheumatologist with the Rheumatology Center of Houston

Interview with Vinicius Domingues, MD, a rheumatologist in Daytona Beach, Florida

Lenfant T, et al. Recombinant Zoster Vaccine in Patients with Rheumatic Diseases: A Retrospective Study of 622 Patients [abstract]. Arthritis & Rheumatology. November 2020. https://acrabstracts.org/abstract/recombinant-zoster-vaccine-in-patients-with-rheumatic-diseases-a-retrospective-study-of-622-patients.

Murphy R. How to Sign Up For a COVID-19 Vaccine in Every State. Verywell Health. February 9, 2021. https://www.verywellhealth.com/covid-19-vaccine-registration-by-state-5096997.

Understanding How COVID-19 Vaccines Work. Coronavirus Disease 2019 (COVID-19). U.S. Centers for Disease Control and Prevention. November 2, 2020. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html.

Understanding mRNA COVID-19 Vaccines. Coronavirus Disease 2019 (COVID-19). U.S. Centers for Disease Control and Prevention. November 23, 2020. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mRNA.html.

Vaccines and Related Biological Products Advisory Committee Meeting. FDA Briefing Document. Pfizer-BioNTech COVID-19 Vaccine. December 10, 2020. https://www.fda.gov/media/144245/download?fbclid=IwAR3RqVgP7tAcHKj5-oWhrPqhkkDPvDekJZ60UXCisFlJb5iOoY6uil9hBRI.

Voysey M, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. The Lancet. December 8, 2020. doi: https://doi.org/10.1016/S0140-6736(20)32661-1.