COVID-19 Vaccine FAQs

El Paso County is vaccinating people age 16 and older.


FOR MORE INFORMATION ON THE COVID-19 VACCINE:

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Monday through Friday,
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COVID-19 VACCINE HOTLINE
1-877-COVAXCO (1-877-268-2926)
Available 24 hours a day, 7 days a week.
Answers available in multiple languages.

Frequently Asked Questions

Like all vaccines, COVID-19 vaccines must meet safety and effectiveness requirements set by the Food and Drug Administration (FDA) before they are made available to the general public.

Like all vaccines, COVID-19 vaccines are required to meet the Food and Drug Administration’s (FDA) safety and effectiveness requirements before they are made available to the public. There are several factors that helped accelerate the development and testing of COVID-19 vaccines, including major government funding and technological advances. Usually, vaccine development and trials happen one after the other, and it can take some time. For COVID-19 vaccines, the federal government provided substantial additional funding to conduct vaccine development and trials at the same time, making the process more efficient. While it was a faster process, it was still a rigorous process. To ensure vaccines are safe and effective, the FDA required the same three phases of clinical trials it does for any vaccine.

In certain emergency situations, the FDA may issue an Emergency Use Authorization (EUA) to allow an investigational vaccine to be available to the general public. Read more about what that means in our Emergency Use Authorization FAQ below. 

Can I get the vaccine right now?

  • People age 16 and older are now eligible to receive a COVID-19 vaccine. All Coloradans over the age of 16 are eligible to receive the Pfizer vaccine, and all Coloradans over the age of 18 are eligible to receive the Moderna or Janssen (Johnson & Johnson) vaccine.
  • The Pfizer vaccine is authorized for people who are age 16 and older. The Moderna and Janssen (Johnson & Johnson) vaccines are authorized for adults 18 and up. Anyone younger than 16 years old should not get either vaccine unless they are enrolled in a clinical trial. 
  • It’s important to know that vaccine providers may have varying amounts of vaccine during any given week. Vaccine providers are working as fast as they can to set up appointments for when they have the vaccine. Note that these locations are NOT open for walk-in appointments. They should be contacted directly for more information. 

Where can I get a vaccine?

Please visit our How will I get the vaccine? web page to view a list of providers and a vaccine provider map.

Do 16- and 17-year-olds need to be accompanied by a parent or guardian at their vaccine appointments?

No. Minors may go to their vaccine appointments unaccompanied as long as parental consent is collected and shared prior to the appointment. This can be done through Colorado’s COVID-19 Vaccine Screening and Administration Form (view in Spanish) or through the vaccine provider’s online scheduling system. The provider may also obtain consent by phone and document it in the patient’s record.

Will the COVID-19 vaccine make me sick?

  • You may experience mild to moderate side effects after receiving the vaccine. Side effects typically go away on their own after a few days. The most commonly reported side effects are: 
    • Pain, swelling, and redness at the injection site.
    • Pain, tenderness and swelling of the lymph nodes in the same arm of the injection.
    • Fatigue.
    • Headache.
    • Muscle pain.
    • Chills.
    • Joint pain.
    • Nausea/vomiting.
    • Fever.
  • Different people may experience different side effects, even if they receive the same vaccine. 
  • The process of building immunity can cause symptoms. These symptoms are normal and show that your body’s immune system is responding to a vaccine. Other routine vaccines, like the flu vaccine, have similar side effects.
  • If you experience discomfort after the first dose of the Pfizer or Moderna vaccine, it is very important that you still receive the second dose a few weeks later for full protection.
  • For in-depth information about the side effects of the vaccines, see the CDC’s report on the Pfizer vaccine, the Moderna vaccine, and the Janssen (Johnson & Johnson) vaccine.

I'm concerned about a serious reaction to the vaccine.

Allergic Reactions

  • Although it is rare, the COVID-19 vaccines may cause mild allergic reactions in some people, like itching or rash. In extremely rare cases, some people may have a severe allergic reaction (e.g.anaphylaxis). If this occurs, vaccination providers can effectively and immediately treat the reaction.
  • Anaphylaxis after receiving a COVID-19 mRNA vaccine is rare and occurs in approximately 2 to 5 people for every million vaccinated based on events reported to Vaccine Adverse Event Reporting System (VAERS). Similar data are not available yet for the Janssen (Johnson & Johnson) vaccine.
  • The health care provider administering your vaccine will monitor you for any allergic reactions you may have after getting vaccinated. They will watch you for at least 15 minutes after the injection (or for 30 minutes if you have a history of anaphylaxis or if you have had an immediate allergic reaction of any severity to a vaccine or injectable therapy). 
  • If you had a reaction following a vaccination, contact your health care provider. You can also submit a report to the Vaccine Adverse Event Reporting System (VAERS).

Immunocompromised people

  • Immunocompromised people may receive a COVID-19 vaccine if they have no contraindications or reason to believe that getting the vaccine would be harmful to them. However, it is important to talk to your health care provider if you have questions about the unknown safety and effectiveness of the vaccine in immunocompromised populations, as well as the potential for reduced immune responses.
  • People living with HIV, other immunocompromising conditions, or who take immunosuppressive medications or therapies might be at increased risk for severe COVID-19 disease. There is currently not enough data to establish vaccine safety and efficacy in these groups. 
  • People with stable HIV infection were included in phase 2 and 3 clinical trials, though data specific to this group are not yet available. 
  • None of the currently available vaccines contains the virus that causes COVID-19.s. A COVID-19 vaccine cannot give you COVID-19.

Serious side effects

  • Serious side effects (also known as adverse events) are extremely rare. The federal government takes all reports of vaccine adverse events seriously.
  • The CDC has not found any patterns in reported adverse events that would suggest a safety problem with the authorized COVID-19 vaccines.
  • CDC uses many vaccine safety monitoring systems, including the Vaccine Adverse Event Reporting System (VAERS), to watch for adverse events after vaccination. VAERS is useful for quickly detecting unusual or unexpected patterns of adverse event reporting that might signal a possible safety problem with a vaccine.
  • VAERS accepts reports of any adverse event following vaccination, even if it is not clear that the vaccine caused a serious side effect. 
  • CDC, FDA, and other federal partners will continue to monitor the safety of COVID-19 vaccines. Find out more on CDC’s Selected Adverse Events Reported after COVID-19 Vaccination

Should I take over-the-counter medication like Tylenol or Advil before getting vaccinated to help with the side effects?

  • Avoid taking over-the-counter pain or fever medications before getting vaccinated. There is a theoretical possibility that doing so might reduce vaccine effectiveness. 
  • If it is normally safe for you to do so, you can take over-the-counter pain or fever medication after you receive the vaccine and once you start to feel side effects.

Cost will not be an obstacle to getting vaccinated against COVID-19.

  • The vaccine is free. Providers should not ask you to pay for the vaccine or other administrative costs, regardless of your insurance status. If you have insurance, the provider may seek reimbursement from your health insurance company for these fees, but you should not be charged. 
  • In the unlikely event that your provider requires payment for your vaccine appointment, you should ask questions about what you are being charged for and why. You should ask for an itemized bill or receipt from the provider and then seek reimbursement from your insurance company.
  • If you encounter problems with your insurance company, you can contact the Division of Insurance by phone at 303-894-7490 or by email at [email protected].
  • If someone is making you pay for a vaccine or a vaccine appointment, it may be a scam. You can report potential vaccine scams to the Colorado Attorney General’s Office at stopfraudcolorado.gov.
  • Learn more about getting the vaccine in this FAQ.

Can children 15 years old and younger get the vaccine?

  • The Pfizer vaccine is authorized for people who are age 16 and older. The Moderna and Janssen (Johnson & Johnson) vaccines are authorized for adults 18 and up. Anyone younger than 16 years old should not get a vaccine unless they are enrolled in a clinical trial. 
  • Although children as young as 12 years old were enrolled in the Pfizer study, there was not enough information for the FDA to give authorization for use under the age of 16. 
  • Currently, Pfizer and Moderna are enrolling 12-17 year olds in their mRNA vaccine clinical trials with the goal of making a COVID-19 vaccine available for children in the near future.

Can I get the vaccine if I'm pregnant or breastfeeding?

  • Pregnant or breastfeeding people may choose to be vaccinated when the vaccine becomes available to them. Talking to a health care provider may help with deciding whether to get the vaccine, but it is not required for vaccination.
  • Based on current knowledge, experts believe that the currently authorized COVID-19 vaccines are unlikely to pose a risk for pregnant or breastfeeding people or their babies. However, pregnant and breastfeeding people were not included in any of the clinical trials for currently authorized COVID-19 vaccines so there is little data on the  safety of the vaccines in pregnant or breastfeeding people. Data show that while the overall risk for pregnant people with COVID-19 is low, they do have an increased risk of severe illness or death.
  • Currently authorized COVID-19 vaccines are not thought to be a risk to breastfeeding babies.
  • The Academy of Breastfeeding Medicine recommends that lactating individuals who get the vaccine continue breastfeeding their babies after being vaccinated. Breast milk contains antibodies and other components that can boost babies’ immune systems and protect babies from getting sick. Early research has shown COVID-19 antibodies are present in breast milk. It is believed that antibodies created after a breastfeeding individual receives the vaccine may also transfer into breast milk and could provide some protection to the baby.
  • For more information about COVID-19 vaccines and pregnancy, see CDPHE’s Pregnancy and breastfeeding FAQ.

Can I get the vaccine if I'm immunocompromised?

  • Immunocompromised people may receive a COVID-19 vaccine if they have no contraindications or reason to believe that getting the vaccine would be harmful to them. However, it is important to talk to your health care provider if you have questions about the unknown safety and effectiveness of the vaccine in immunocompromised populations, as well as the potential for reduced immune responses.
  • People living with HIV, other immunocompromising conditions, or who take immunosuppressive medications or therapies might be at increased risk for severe COVID-19 disease. There is currently not enough data to establish vaccine safety and efficacy in these groups. 
  • People with stable HIV infection were included in phase 2 and 3 clinical trials, though data specific to this group are not yet available. 
  • None of the currently available vaccines contains the virus that causes COVID-19.s. A COVID-19 vaccine cannot give you COVID-19.

What vaccines are available?

  • Currently, the U.S. Food and Drug Administration (FDA) has authorized three COVID-19 vaccines from the companies Pfizer, Moderna, and Janssen (Johnson & Johnson). The FDA authorized the Pfizer vaccine on December 11 for people 16 years and older and authorized the Moderna vaccine on December 18 for adults 18 and older.  The FDA authorized the Janssen (Johnson & Johnson) vaccine on February 27 for adults 18 and older.
  • CDC provides detailed profiles for each available vaccine on their Different COVID-19 Vaccines page.

Is one type of vaccine recommended over the others?

  • None of the vaccines is recommended over the other. We encourage you to get whichever vaccine type or product is offered to you when you become eligible for vaccination. Getting vaccinated greatly reduces the risk of illness if you are exposed to the virus. 
  • Learn more about how COVID-19 vaccines work in this FAQ.

Do I still need to get a COVID-19 vaccine if I have had COVID-19 and recovered?

  • It is currently unknown how long natural immunity lasts after recovering from COVID-19. Early evidence suggests natural immunity from COVID-19 may not last very long in some people, and cases of reinfection have been reported. So even if you have had COVID-19 and recovered, you should plan to get a vaccine when it is your turn. 
  • If you had a COVID-19 infection, CDC says you may wait a few months after your infection before getting the vaccine as re-infection risk is low during this time. However, you may choose to get the vaccine earlier than that as long as you have recovered from your infection.
  • If you received a COVID-19-specific antibody treatment (e.g. monoclonal antibodies or convalescent plasma) while you were sick with COVID-19, you should wait at least 90 days after receiving the antibody treatment before getting the vaccine. 
  • Data from clinical trials suggest that the Pfizer and Moderna vaccines are safe and effective in people who have recovered from a previous COVID-19 infection.
  • Learn more about immunity in this FAQ. 

Do I have to get the second dose of the vaccine at the same location where I got my first dose?

  • We strongly recommend that you get both doses from the same vaccine provider. Doing so ensures that you are getting the same vaccine product for both doses at the right time. 
  • Note that the second dose should be the same vaccine product as the first dose.

Will the vaccine still be effective if I wait more than a few weeks between my first and second doses? What happens if I get the second dose too early or too late?

  • You should make every effort to receive the second dose of your COVID-19 vaccine exactly 21 days after the first dose for Pfizer and 28 days after the first dose for Moderna. Plan accordingly so that you are able to get the second dose of your vaccine at the right time.
  • If it isn’t possible to get the second dose on the right day, the second dose can be given early, up to 4 days before it is due. Additionally, the second dose can be given as late as 42 days (6 weeks) after the first dose. This is called a grace period. 
  • There is not a lot of data on how well the vaccine will work if given outside of the grace period. But if the second dose is accidentally given outside the grace period, there is no need to restart the vaccination series.

What happens if I get a different vaccine product for my second dose?

  • Every effort should be made to make sure your second dose is the same vaccine product as the first dose. Studies have shown that the vaccines are safe and work well when the same vaccine product is used for both doses. 
  • If, for some reason, you receive a different product for your second dose, you do not need to repeat the vaccination again with additional doses.

Is it bad for my health or dangerous if I get only one dose (of a two-dose vaccine)?

Although current studies show that it takes two doses of the Pfizer or Moderna vaccine to be 95% effective, there is no evidence that taking only one dose will have any harmful effects on your health. If you do not receive the second dose, you will not be fully immunized and be at higher risk of getting symptomatic COVID-19 than if you received both doses.

When will I be protected after I get the vaccine?

  • You will not be immediately protected from COVID-19 after receiving the vaccine. Studies show that it takes about two weeks after your last dose for your body to fully  protect itself against illness.
  • It may be possible that someone who has been vaccinated against COVID-19 could develop a mild or asymptomatic infection and even possibly spread the virus to others. More studies are needed to determine this. So in the meantime, it is important to continue taking COVID-19 precautions. Continue wearing masks and practicing physical distancing. 
  • While no vaccine is 100% effective, Pfizer and Moderna have reported that their vaccines are about 95% effective.

Do I still need to wear a mask and socially distance after receiving a vaccine?

  • After getting fully vaccinated, it’s important to continue taking precautions while you are in public and at work, like wearing a well-fitting mask and keeping at least 6 feet of physical distance from other people. This is because you might still be able to spread the virus to unvaccinated people.
  • People are considered fully vaccinated: 
    • 2 weeks after their second dose in a 2-dose series, like the Pfizer or Moderna vaccines. 
    • 2 weeks after a single-dose vaccine, like Janssen’s (Johnson & Johnson) vaccine.
  • If you are fully vaccinated, you may visit other people who have been fully vaccinated indoors without wearing masks or physically distancing in small groups.
  • If you are fully vaccinated, you may also visit with unvaccinated people from a single household who are at low risk for severe COVID-19 disease indoors without wearing masks or physical distancing. 
  • We recommend continuing to avoid medium and large gatherings with multiple households even after vaccination. 
  • For more information about precautions you should take after vaccination, please see CDC’s webpage When You’ve Been Fully Vaccinated: How to Protect Yourself and Others
  • Learn more about how to protect yourself in this FAQ.

Do I need to be a U.S. citizen to get a vaccine?

  • No. You do not need to be a U.S. citizen, and you will not need to prove lawful presence to get a COVID-19 vaccine in Colorado.
  • Know that the Department of Homeland Security announced that vaccination sites will be considered sensitive locations. This means that ICE will not carry out enforcement activities at or near vaccination sites. 
  • State and local public health agencies will never share your information for any immigration or law enforcement purposes. And receiving the COVID-19 vaccine will not count against you in any public charge determinations.
  • Learn more about getting the vaccine in this FAQ.

Do any of the vaccines contain harmful ingredients?

  • Today’s vaccines use only the ingredients they need to be as safe and effective as possible. Each ingredient in a vaccine serves a specific purpose: provide immunity (protection) and keep the vaccine safe and long-lasting.
  • All vaccines contain antigens or elements that trigger the production of antigens. Antigens make vaccines work. They prompt the body to create the immune response needed to protect against infection. Antigens come in several forms. The form used in a vaccine is chosen because studies show it is the best way to protect against a particular infection. 
  • Other ingredients in vaccines may include preservatives, to keep germs out; adjuvants, to help boost the immune response to the vaccine; and additives, which help the vaccine stay effective while being stored. Each ingredient has a specific function and has been rigorously studied. These ingredients are safe for humans in the amounts used in vaccines.
  • For a full list of ingredients, please see each vaccine’s fact sheet (ModernaPfizer, or Janssen).

Can I get COVID-19 from a vaccine?

  • No. It is not possible to get COVID-19 from a vaccine, but you may feel some side effects like fever, chills, and fatigue. The current COVID-19 vaccines use temporary pieces of genetic code from the virus to stimulate your body’s immune response. This cannot cause COVID-19. The goal of each vaccine is to provide your body with the tools it needs to fight the COVID-19 virus if you were to get infected. 
  • Learn more about vaccine side effects and immunity in this FAQ.

How to mRNA vaccines work?

  • The Pfizer and Moderna vaccines are both mRNA vaccines. These vaccines help our bodies build an immune response to the COVID-19 virus. The mRNA vaccine temporarily teaches our cells how to make a harmless spike protein that is unique to the virus that causes COVID-19. After our cells temporarily make copies of the protein, our immune system recognizes that the protein should not be in our body and builds antibodies to remember how to fight the virus if we are infected in the future. 
  • An antibody is a protein produced by your immune system that can recognize a specific type of virus in your body. When you get exposed, your body’s antibodies are able to recognize proteins on the surface of the COVID-19 virus to attack and stop it from replicating in your body.
  • For a visual explanation of how mRNA vaccines work, watch Stat’s video “What are mRNA vaccines?”
  • To learn more, visit CDC’s Understanding How COVID-19 Vaccines Work.

How do viral vector vaccines work?

  • The Janssen (Johnson & Johnson) vaccine is a viral vector vaccine. Like mRNA vaccines, viral vector vaccines help our bodies build an immune response to the COVID-19 virus. Viral vector vaccines temporarily teach our cells how to make a harmless spike protein that is unique to the virus that causes COVID-19. 
  • While mRNA vaccines use single-stranded genetic code called mRNA to write down instructions for this protein, viral vector vaccines use double-stranded DNA. Scientists put this DNA into a different virus called Adenovirus 26. Adenoviruses are common viruses that typically cause colds or flu-like symptoms. The Janssen (Johnson & Johnson) vaccine uses a modified adenovirus that can give your cells instructions about how to make spike proteins. This adenovirus can’t make you sick.
  • After our cells temporarily make copies of the protein, our immune system recognizes that the protein should not be in our body and builds antibodies to remember how to fight the virus if we are exposed in the future. 
  • An antibody is a protein produced by your immune system that can recognize a specific type of virus in your body. When you get exposed, your body’s antibodies are able to recognize proteins on the surface of the COVID-19 virus to attack and stop it from replicating in your body.
  • To learn more, visit CDC’s Understanding Viral Vector COVID-19 Vaccines.

What are the major differences between mRNA (Pfizer, Moderna) and viral vector (Janssen/ Johnson & Johnson) vaccines?

  • All authorized COVID-19 vaccines teach your body how to make spike proteins like the ones that cover the COVID-19 virus. Your body learns how to fight the spike protein without having to fight off the full virus. If you are exposed to a person with COVID-19 after vaccination, your body will recognize the spike proteins and remember how to fight them before the virus makes you sick.
  • While all COVID-19 vaccines contain instructions for how to make spike proteins, these instructions are written in different ways. Viral vector vaccines, like the Janssen (Johnson & Johnson) vaccine, use a piece of double-stranded DNA to teach your body how to fight COVID-19. mRNA vaccines, like the Pfizer and Moderna vaccines, use single-stranded mRNA. The goal of every vaccine is the same -- they just use a different strategy to achieve that goal.
  • Janssen’s (Johnson & Johnson) vaccine is more durable than either of the authorized mRNA vaccines. It can be stored for up to three months at normal refrigeration temperatures (36–46°F or 2–8°C).
  • The Janssen (Johnson & Johnson) vaccine only requires one dose. The Pfizer and Moderna vaccines require two doses.

Can mRNA vaccines change my genes?

No, mRNA from the COVID-19 vaccines does not affect your DNA. mRNA is a naturally occurring and temporary genetic molecule that instructs your cells how to create spike proteins in the body. Minutes to hours after the mRNA is read by the cell, the body destroys the temporary mRNA using a special enzyme. After your cells make copies of the virus’ protein, your immune system is triggered and recognizes that the protein should not be in your body. Your body then builds antibodies so that it remembers how to fight the virus if you are exposed in the future.

Can viral vector vaccines change my genes?

  • No, the DNA delivered by the viral vector won’t make any long-term changes to your body’s genes. The DNA goes into some of your cells to give temporary instructions on how to make spike proteins. When the vaccinated cells die, the DNA does not affect any other cells. Viral vector vaccines cannot change your body’s genome.
  • After your cells make copies of the virus’ protein, your immune system is triggered and recognizes that the protein should not be in your body. Your body then builds antibodies so that it remembers how to fight the virus if you are exposed in the future.

Can I travel safely once I am fully vaccinated?


The CDC has issued guidance for domestic travel and international travel.

CDC recommends delaying travel until you are fully vaccinated, because travel increases your chance of getting and spreading COVID-19. If you are not fully vaccinated and must travel, follow CDC’s recommendations for unvaccinated people.

More questions?

The Colorado Department of Public Health and Environment has answers to many common questions here.

General

Flu Vaccine and COVID-19 Vaccine

Who should get a flu vaccine?

Everyone age 6 months and older should get the flu vaccine annually.

Why should I get a flu vaccine?

Getting a flu vaccine is more important than ever because we need to ensure our healthcare systems aren’t overwhelmed during the pandemic

Will a flu vaccine protect me against getting COVID-19?

Getting a flu vaccine will not protect you against COVID-19, but a flu vaccination will reduce your risk of getting the flu and being hospitalized because of the flu.

Am I more at risk of getting COVID-19 if I get a flu vaccine?

Vaccine Safety and Development

For additional information, visit CDC: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety.html

Who approves the use of vaccines in the United States?

The Food and Drug Administration (FDA) licenses and approves the use of vaccines. Before the FDA approves a vaccine, the manufacturer must do rigorous research and testing to ensure the vaccine’s safety and effectiveness. The FDA independently reviews and verifies the information from these tests. It then decides whether the vaccine can be given to the public. 

How are vaccines tested for safety and effectiveness?

Vaccines must go through a detailed scientific evaluation before they can be submitted to the FDA for approval. Each phase of the evaluation includes three different clinical research studies. In the clinical research study or trial, the vaccine is tested on people who volunteer to be part of the study. Each clinical trial emphasizes safety of the vaccine on people. As the research moves through to the next phase, the group of volunteers becomes bigger to include more diversity in people and circumstances.

  • Phase 1 involves a small group of volunteers to evaluate safety and common side effects of the vaccine.
  • Phase 2 involves a larger group of volunteers to gather information on safety, vaccine dosing and how effective the vaccine will be in preventing the targeted disease.
  • Phase 3 involves the largest group of volunteers and a longer time frame than the earlier studies. Along with safety and side effects, most Phase 3 studies focus on efficacy -- how well the vaccine works -- and compare people who have received the vaccine to those who have not received the vaccine. This phase provides the most firm scientific evidence possible showing the difference between people who have been vaccinated and people who have not been vaccinated.

Who are the volunteers in vaccine clinical trials?

  • The scientific community has made a concerted effort to recruit a diverse group of volunteers for every phase of COVID-19 vaccine trials. The goal is to test for safety and effectiveness in populations disproportionately impacted by COVID-19 disease and death, including Black/African American, Latino/a and American Indian/Alaska Native/Native Hawaiian communities. 
  • The COVID-19 Prevention Network (CoVPN) was formed by the National Institute of Allergy and Infectious Diseases (NIAID) at the U.S. National Institutes of Health to help address this issue. To read more about these efforts, visit coronaviruspreventionnetwork.org.

What happens after clinical trials are finished?

  • Once the clinical trials can demonstrate vaccine safety and effectiveness at an appropriate dose, the manufacturer applies to the FDA to license the vaccine so that it can be used in the general population. 
  • The FDA reviews all of the data from the phased clinical studies using rigorous protocols and procedures. The vaccine is not licensed or approved until the FDA can ensure the vaccine is safe and effective.
  • In emergencies, such as the current COVID-19 pandemic, vaccines can also be authorized through an Emergency Use Authorization (EUA).
  • Read the Emergency Use Authorization (EUA) FAQs below.

Who else reviews the safety and efficacy data from the clinical trials?

  • For each vaccine licensed by the FDA, the Advisory Committee on Immunization Practices (ACIP) carefully reviews all available data about the vaccine from clinical trials and other studies, and makes recommendations for vaccine use in the general public. Recommendations include groups that should and should not receive the vaccine, as well as the timing, volume, number, and spacing of doses in a vaccine series. 
    • The ACIP is a federal advisory committee that provides guidance on the best use of vaccines to the Centers for Disease Control and Prevention (CDC) and U.S. Department of Health and Human Services (HHS). 
  • Once ACIP recommendations have been reviewed and approved by the CDC and HHS, they are published in CDC’s Morbidity and Mortality Weekly Report (MMWR). The MMWR publication represents the final and official CDC recommendations for immunization of the U.S. population.

How is vaccine safety monitored after a vaccine has been approved or authorized?

  • FDA and CDC closely monitor vaccine safety after the public begins using the vaccine. There are four main vaccine safety monitoring systems:
    • Vaccine Adverse Event Reporting System (VAERS) - VAERS is an early-warning system that collects and analyzes reports of any problems that happen after vaccination. Anyone can submit a report, including parents, patients, and health care professionals.
    • Vaccine Safety Datalink (VSD) and Post-Licensure Rapid Immunization Safety Monitoring (PRISM) - VSD and PRISM are a collaboration between CDC and several health care organizations to actively monitor vaccines given to over 114 million people.
    • Clinical Immunization Safety Assessment Project (CISA) - CISA is a collaboration between CDC and seven medical research centers to answer complex safety questions. CISA conducts clinical research studies to further understand vaccine safety and recommend prevention strategies for adverse events following immunization.
  • Vaccine recommendations may change if safety monitoring reveals new information about vaccine risks, such as a new serious side effect. Safety alerts are sent to health care providers if there are any new problems. In some cases, a vaccine may be removed from the market. For example, in 1999, RotaShield®, a vaccine for rotavirus, was taken off the U.S. market after reports of increased cases of bowel obstructions in infants who had received the vaccine.

Emergency Use Authorization

What is an Emergency Use Authorization?

  • In certain emergency situations, the Food and Drug Administration (FDA) may issue an Emergency Use Authorization to provide more timely access to critical medical products when there are no other options available. An EUA permits the FDA to release unapproved medical products or allow for unapproved uses of medical products that have met certain criteria, to treat, diagnose, or prevent serious or life-threatening diseases.
  • The EUA process is different from the full approval process because in some emergency situations, we cannot wait for all the evidence needed for the full FDA approval. 
  • Instead, the FDA evaluates the risks and benefits of a product very quickly using the scientific evidence that is available.

Why do EUAs exist?

EUAs were initially introduced in 2004 to prepare for bioterrorism attacks. Under an EUA, the government is able to authorize medical treatments and products in the event of a Chemical, Biological, Radiological, and Nuclear (CBRN) attack.

What is the criteria for an EUA?

The FDA may issue an EUA for a medical product if it meets the following criteria:

  • The disease or CBRN agent in question can cause a serious or life-threatening illness or condition. 
  • There is reasonable belief, after looking at all the scientific evidence, that the product may be effective for its intended use. The phrase “may be effective” lowers the standards for scientific evidence typically required for FDA approvals.
  • The known and potential benefits outweigh the known and potential risks. The FDA will look at all available scientific evidence to determine the risk and benefits of a product. 
  • There is no adequate, approved, and available alternative to the product.

Is it common for vaccines to be authorized under an EUA?

A vaccine intended for wide distribution to the general public has not been released under an EUA in the past. The only vaccine authorized under an EUA prior to the COVID-19 pandemic was an anthrax vaccine in 2005. This vaccine was given to certain military personnel who were at heightened risk of exposure to anthrax.

When have EUAs been issued in the past?

Although not common, EUAs have been issued multiple times in the past for tests, treatments and medical equipment.  

  • In 2009, EUAs were issued for diagnostic tests, personal protection equipment and certain antiviral drugs during the H1N1 Swine Influenza pandemic.  
  • In 2013, EUAs were issued for diagnostic tests related to H7N9 influenza and Middle East Respiratory Syndrome (MERS). 
  • Several EUAs have already been issued for some COVID-19 tests and treatments: hydroxychloroquine, the antiviral medication remdesivir (recently approved), and convalescent plasma. However, the EUA for hydroxychloroquine was later withdrawn due to its lack of effectiveness in the treatment of COVID-19 and potential risk to patients.