COVID-19 Vaccine

[COVID-19 Vaccine Distribution. Phase 1 Winter.  1A Highest-risk health care workers and individuals. People who have direct contact with COVID-19 patients for 15 minutes or more over a 24-hour period. Long-term care facility staff and residents. Phase 1B Coloradans age 70+, moderate-risk health care workers, first responders, frontline essential workers, and continuity of state government. Health care workers with less direct contact with COVID-19 patients (e.g. home health, hospice, pharmacy, dental, etc.) and EMS. Firefighters, police, COVID-19 response personnel, correctional workers, and funeral services. People age 70 and older.---------Frontline essential workers in education food and agriculture, manufacturing, U.S. postal service, public transit and specialized transportation staff, grocery, public health, frontline essential human service workers, and direct care providers for Coloradans experiencing homelessness. Essential officials from executive, legislative and judicial branches of state government. Essential frontline journalists. Phase 2. Spring. Higher-risk individuals and other essential workers. People age 60-69. People age 16-59 with obesity, diabetes, chronic lung disease, significant heart disease, chronic kidney disease, cancer or are immunocompromised. Other essential workers and continuity of local government. Adults who received a placebo during a COVID-19 vaccine clinical trial. Phase 3. The general public. Anyone age 16-59. Timeline subject to change based on supply chain. Prioritization subject to changed based on data, science, availability. Revised 12/30/2020.’]

Colorado is in Phase 1A and 1B.


303-389-1687 or 877-462-2911
Monday through Friday,
9 a.m. - 10 p.m.
Saturday and Sunday,
9 a.m. - 5 p.m.
Answers available in multiple languages.
Or call Pikes Peak United Way at 2-1-1.

The initial supply of COVID-19 vaccine(s) is very limited for several months. This means that a vaccine will not be immediately available to everyone who wants one. To be as fair and efficient with distribution as possible, the state has developed a phased approach to vaccine distribution to save lives and end the crisis that has been brought on by the pandemic as quickly as possible. By vaccinating people who are most likely to get COVID-19 first, we can keep more Coloradans safe.

Colorado’s COVID-19 Vaccination Plan will evolve as more information about vaccines becomes available and stakeholder engagement continues. We will update this page as often as necessary when new information becomes available. 

For more in-depth information please visit the Colorado Department of Public Health and Environment:

What Coloradans should know about a COVID-19 vaccine

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. 

Are there COVID-19 vaccines right now?

Yes, there are two COVID-19 vaccines, but they are being distributed in a phased approach. Colorado is currently vaccinating eligible Coloradans for Phase 1A and Phase 1B. After all of Phase 1 is complete, we will proceed with Phase 2 and 3. Several additional COVID-19 vaccines are still under development. 

Distributing a COVID-19 vaccine to the entire state will take time.

While we are planning to act swiftly, we expect it could take several months, or potentially more than a year, to distribute a vaccine to everyone who wants one, especially because most of the vaccine candidates require two doses. We are working closely with local public health agencies, health care providers, pharmacies and diverse community partners to distribute the vaccine as equitably and efficiently as possible. COVID-19 Vaccine Distribution Timeline

Where can I get a vaccine?

  • The majority of early Phase 1A recipients will receive the vaccine through their employer or through the federal government’s  Pharmacy Partnership for Long-term Care (LTC) Program
  • Please contact your employer if you are a Phase 1A frontline health care worker and have not received information. 
  • If you are in another phase, or need more information about vaccination please visit our How will I get the vaccine? web page.

The state will distribute vaccines in phases until it is more widely available.

Because the initial supply of vaccine is very limited, it will be distributed first to people most at risk for COVID-19. Phase 1A includes the highest-risk health care workers and individuals (including long-term care facility staff and residents). Phase 1B currently includes Coloradans aged 70-plus, moderate-risk health care workers, first responders, frontline essential workers, essential government officials and essential frontline journalists. The next stage will be higher risk individuals (including people aged 60-69 and those with certain health risks) and other essential workers. The final phase will be for the general population. 

Right now, children and pregnant women are not included in any phase because no vaccine candidates are currently being tested in pregnant women and only one candidate is being tested in children 12 years and older. We fully anticipate being able to vaccinate these populations once the FDA and CDC make the recommendation to do so.

Colorado’s phases are based on federal guidelines to distribute a limited supply of vaccines in a fair, ethical, and transparent way.

When do we move to the next phase?

In the early stages of vaccine distribution, health care providers will provide information to the Colorado Department of Public Health and Environment on how much vaccine they need and how many people are getting vaccinated. Once state officials believe enough vaccine has been distributed to those who want a vaccine in the first phase, they will move to the next phase. The speed at which states and counties are able to move through the phases will largely depend on the supply of vaccine.

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

As a condition of receiving free COVID-19 vaccines from the federal government, vaccine providers will not be allowed to charge patients for the vaccine. It is possible that providers may charge a fee to administer the vaccine. We expect that most public and private insurance companies will cover this fee so that there is no cost to the person getting vaccinated. This will also be the case for people without health insurance through the Provider Relief Fund, administered by the Health Resources and Services Administration (HRSA).

Does the vaccine protect against all strains of COVID-19?

While there are several known variants of COVID-19, current evidence suggests the vaccine will protect against all of them.

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), keep the vaccine safe and long-lasting, and for the production of the vaccine.
  • 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.

How to mRNA vaccines work?

  • mRNA vaccines help our bodies build an immune response to the COVID-19 virus. The mRNA vaccine teaches our cells how to make a harmless protein that is unique to the virus that causes COVID-19. After our cells 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 infected, 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.
  • It's important to know that mRNA from the COVID-19 vaccine never enters the nucleus of the cell and does not affect or interact with your DNA. mRNA are naturally occurring genetic molecules that instruct our cells how to create proteins that build, maintain, and repair things in the body. Minutes after our cells make the proteins, the body destroys the mRNA using a special enzyme. mRNA in vaccines are designed to withstand the enzyme a little bit longer (a few days at most) so that our cells can create enough of a harmless protein that is unique to the virus. After our cells make copies of the virus’ protein, our immune system is triggered and recognizes that the protein should not be in our body. Our body then builds antibodies so that it remembers how to fight the virus if we are infected in the future.
  • To learn more, visit CDC’s Understanding How COVID-19 Vaccines Work.

I'm concerned about serious side effects. What do I need to know?

Allergic Reactions

  • Although it is rare, the COVID-19 vaccines may cause mild allergic reactions in some people, like itching or rash. Extremely rarely, some people may have a severe allergic reaction like anaphylaxis. 
  • People with a history of severe allergic reactions, such as anaphylaxis, to any component of a COVID-19 vaccine should not receive that vaccine. 
  • People who have had severe allergic reactions to other vaccines in the past should use caution and talk with their health care provider before deciding whether or not to get vaccinated. 
  • People with a history of severe allergic reactions unrelated to any vaccine may get the COVID-19 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). 
  • Sites administering COVID-19 vaccines should have health care staff, medications, and supplies for managing anaphylaxis (like epi-pens) on hand in case someone experiences a severe allergic reaction to the vaccine.
  • For more information about monitoring for severe allergic reactions, see the CDC’s Interim Considerations: Preparing for the Potential Management of Anaphylaxis at COVID-19 Vaccination Sites.
  • CDC and FDA are continuously monitoring for allergic reactions in vaccine recipients. They will investigate reports quickly and update recommendations as more information becomes available.

Immunocompromised people

  • People living with HIV, other immunocompromising conditions, or who take immunosuppressive medications or therapies might be at increased risk for severe COVID-19. There is currently not enough data to establish vaccine safety and efficacy in these groups. 
  • People with stable HIV infection were included in phase 2/3 clinical trials, though data specific to this group are not yet available. 
  • Immunocompromised individuals may still receive the COVID-19 vaccine if they have no contraindications. However, they should have a conversation with their health care provider about the  unknown vaccine safety profile and effectiveness in immunocompromised populations, as well as the potential for reduced immune responses and the need to continue to follow all current guidance to protect themselves against COVID-19.
  • Because the Pfizer and Moderna vaccines are mRNA vaccines, they do not contain live virus and cannot give you COVID-19.

Serious side effects

  • Science shows that generally the most serious side effects occur within six weeks of vaccine administration. The current available COVID-19 vaccines have been studied for longer than six weeks, and the companies have not identified or reported serious safety concerns. To date, the independent safety monitoring board overseeing Phase 3 trials of the Pfizer and Moderna vaccines has not found any serious safety concerns. The FDA reviews all research before authorizing any vaccine for use. 
  • The FDA and CDC will continue to closely monitor vaccine safety as the public begins using a new vaccine. If safety monitoring reveals new information about vaccine risks, such as new serious side effects, new guidelines may be issued or a vaccine may be removed from the market. Learn more about the vaccine safety monitoring systems.  

How can I start to make a vaccine plan for myself and my family?

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

  • Data from Pfizer’s clinical trials suggest that the Pfizer and Moderna vaccines are likely safe and effective in people who have recovered from a previous COVID-19 infection. The Advisory Committee on Immunization Practices (ACIP) recommends waiting at least 90 days after recovering from COVID-19 before getting the vaccine.
  • 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, and cases of reinfection have been reported. 
  • The Advisory Committee on Immunization Practices (ACIP) makes recommendations on how to best use COVID-19 vaccines, and the FDA authorizes use. We will allow for all permissible uses once they are authorized

Is natural immunity from having COVID-19 better than getting a vaccine?

  • The protection someone gains from having an infection (called natural immunity) varies depending on the disease, and it varies from person to person. Because this virus is new, we don’t know how long natural immunity might last. Some early evidence—based on a small sample size of people—seems to suggest that natural immunity may not last very long.
  • Regarding vaccination, we won’t know how long immunity lasts until we have more data on how well it works over time.
  • Experts are trying to learn more about both natural immunity and vaccine-induced immunity of COVID-19.

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

  • It will take time after the vaccination for your body to respond and make enough antibodies to protect you. This could take up to one to two weeks after your last dose. 
  • Current info suggests that it is possible that someone who has been vaccinated against COVID-19 may still have a mild or asymptomatic infection or spread the virus to others. So it is important to continue taking precautions. Continue wearing masks and practicing physical distancing until it is clear that it is safe to stop.

Administering the vaccine is a joint effort between public and private partners.

So far, more than 1,200 facilities in Colorado have expressed interest in being a COVID-19 vaccine provider. During the initial phase, vaccine providers include local public health agencies and large hospitals and health systems. As the vaccine becomes more widely available, the network of COVID-19 vaccine providers will expand to include doctors’ offices, pharmacies, homeless shelters, colleges/universities, senior centers, school-based health centers and other health and medical locations. 

We cannot wait for widespread vaccination to slow the spread of COVID-19.

We have to continue to follow public health guidance closely now and for the foreseeable future. Prevention methods still include: wearing a mask in public, maintaining at least 6 feet of physical distance from others not in our household, avoiding large crowds, washing our hands often and staying home when we are sick.

Getting a flu shot this year is more important than ever.

The flu vaccine is available now. The state health department recommends everyone age 6 months and older get the flu vaccine, as soon as possible. Getting a flu vaccine will not protect you from COVID-19, but a flu vaccination will reduce your risk of getting the flu. If you have questions about getting both the flu and COVID-19 vaccine when one is available, read our Flu vaccine and COVID-19 vaccine FAQ below or see our Similarities and Differences Between Flu and COVID-19 guidance.

Frequently Asked Questions


What is the purpose of Colorado's Vaccination Plan?

  • The purpose of Colorado's Vaccination plan is to prepare for COVID-19 vaccine distribution throughout the state.
  • The plan provides guidance to individual vaccine providers on who to vaccinate and when. The phased implementation of a COVID-19 vaccine is guidance to both the state and individual vaccine providers, but it is not a law or a mandate.

Who decided on the phases for vaccine distribution?

Colorado’s Phased Implementation Plan for a COVID-19 vaccine was developed through a collaboration between the Governor’s Expert Emergency Epidemic Response Committee’s Medical Advisory Group (a group of medical experts and ethicists), Colorado Department of Public Health and Environment (CDPHE), the Governor’s Office and extensive community engagement with community members and leaders.

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:

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

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.