Frequently Asked Questions about the COVID-19 Vaccine

Published Feb 26, 2021 Updated Apr 2, 2021


Presented by Comunidad Latina de Vashon, Greater Cleveland Congregations, and Union of Concerned Scientists

Section 1 : Topline Questions about the COVID-19 Vaccines

COVID-19 has taken an enormous toll on human health and caused millions of deaths around the world. However, after months of testing and trials, scientists have developed vaccines to protect people from the virus, and they are now being distributed globally.

In the coming weeks or months, a COVID-19 vaccine will become available to you. If you, like many others, have questions about the vaccines, we offer these answers based on the best available scientific information.

How do vaccines work in general?

A vaccine trains a person’s body to fight off a specific virus. Different types of vaccines work in different ways, but all vaccines stimulate the body to make specific immune cells that can fight that virus in the future.

How can I place my trust in COVID-19 vaccines knowing that some doctors have harmed people of color, especially African Americans, when carrying out medical research?

As Black and Brown communities across the United States weigh the decision of whether to take the COVID-19 vaccine, it is important to note that doctors and scientists of color are strongly endorsing the vaccines. Sixty African American health experts from the National Academy of Medicine have reviewed the research and expressed strong confidence in the safety and effectiveness of the vaccines.

Distrust of medical researchers in communities of color, especially African American communities, is a rational response to a long history of medical abuse. African Americans and other people of color in the United States continue to experience more illness, worse outcomes, and die younger compared with white individuals. African American women and Indigenous women are two to three times more likely to die from pregnancy-related causes than white women.

When Dr. Susan Moore, an African American physician, came down with a severe case of COVID-19 in November 2020, her white doctor downplayed Dr. Moore’s reports of pain, initially refused to give her pain medicines, and tried to send her home from the hospital. Dr. Moore said, “I maintain if I was white, I wouldn’t have to go through that.” She later died of COVID-19.

During the 40-year-long Tuskegee Syphilis Study, the African American, low-income participants were denied treatments for their syphilis, a horrible ethical violation that resulted in extreme harm and death to the participants and their families. This is just one example of the long and troubled history of medical racism in the United States, which also includes the Guatemala syphilis experiments, the case of Henrietta Lacks and her legacy, the unnecessary surgeries without anesthesia performed on enslaved women, and the targeting of Indigenous, African American, and Puerto Rican women for involuntary sterilization throughout the 20th century.

In response, the federal government carried out a series of reforms. For instance, the Belmont Report, created in 1976, which was issued in response to the Tuskegee Syphilis Study, requires that all research with human participants follow three ethical guidelines: respecting persons, minimizing risk to participants, and considering issues of justice in how the burdens and benefits of research are distributed across society. In June 2000, the Office for Human Research Protections was established, which is housed in the US Department of Health and Human Services (HHS), to protect human subjects of research. Every university, hospital, and research center is required to carry out detailed ethical reviews of every proposed scientific and medical study to ensure the protection, rights, and safety of participants.

Because vaccines are administered to so many different types of people, vaccine trials are held to an especially high standard of safety. This includes COVID-19 vaccine research, in which a diverse group of scientists, medical doctors, and public health practitioners around the world worked to prove the vaccines would be safe and to ensure research participants would be protected during the trials. Dr. Kizzmekia Corbett, an African American female scientist at the National Institutes of Health (NIH), played a leading role in developing one of the COVID-19 vaccines. By the time you are offered a vaccine, millions of people of all races, genders, and age groups, in multiple countries, from the health care community to political leaders to vulnerable groups including elderly people, will have been safely vaccinated.

How well do the COVID-19 vaccines work?

The US Food and Drug Administration (FDA) first approved the Pfizer-BioNTech vaccine, then the Moderna vaccine, and then the Johnson & Johnson (J&J) vaccine. Large clinical trials with tens of thousands of people were held to test the vaccines’ effectiveness at preventing COVID-19 (Table 1). Half the participants received the vaccine and half received a placebo—a shot containing no active ingredient. Scientists advising the FDA carefully analyzed the Pfizer, Moderna, and J&J data and confirmed that vaccines prevent COVID-19 symptoms, including severe symptoms, thereby protecting people from illness and death. It is not yet known how long their protective effects will last.

Should I be concerned that the J&J vaccine’s effectiveness is lower than the Pfizer and Moderna vaccines?

A vaccine does not need to be 100 percent effective to be considered a good vaccine. The annual flu vaccine, which is designed to protect people from flu strains and slow the spread of flu epidemics, is usually 40 to 60 percent effective. In June 2020, the FDA stated that, in order to be approved by the agency, a COVID-19 vaccine would have to prevent disease or decrease disease severity in at least 50 percent of the people who are vaccinated.

While the numbers may differ between the three vaccines, all three are considered extremely good at preventing you from getting the worst COVID-19 symptoms. Specifically, the J&J vaccine is 100 percent effective at preventing fatal cases of COVID-19 and is 85 percent effective at stopping severe COVID-19 symptoms that can result in hospitalization. The FDA noted that the J&J vaccine may be somewhat less effective in preventing illness in adults older than 60 who also had medical risk factors, but this finding was not certain and requires more research. In December 2020, J&J started a clinical trial to test a two-dose regimen, which Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said could further increase the vaccine’s effectiveness.

How do the COVID-19 vaccines work?

There are three types of COVID-19 vaccines currently undergoing large-scale clinical trials or have been approved for use in the United States. None can give you COVID-19 and none interact with your DNA.

  1. One type, including the not-yet-approved Novavax vaccine, presents the body with harmless pieces of the virus that causes COVID-19. This technique has been used to make vaccines for hepatitis B, whooping cough, and other diseases.
  2. Another type, including the J&J and AstraZeneca vaccines, uses the weakened, live version of a different virus that contains some of the genetic material of the virus that causes COVID-19. This technique, in use since the 1970s, recently led to the development of an Ebola vaccine.
  3. The third type, including the Pfizer and Moderna vaccines, are called messenger RNA (mRNA) vaccines, which teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. Researchers have used this technique for decades to study cancer and develop vaccines for the flu, rabies, and Zika.
Are the COVID-19 vaccines safe?

Yes. Getting a COVID-19 vaccine is associated with very few risks. Among the tens of thousands of people who received a Pfizer, Moderna, or J&J vaccine in the clinical trials, the most common side effects experienced were pain at the injection site, fatigue, headaches, muscle pain, joint pain, chills, or fever—the vast majority of which disappeared in a few hours or a few days. In rare cases, you can develop an allergic reaction, usually within the first 15 minutes of receiving the vaccine. The FDA is currently investigating a very rare allergic reaction to the Pfizer vaccine that has occurred in a handful of individuals. Clinical trials are currently taking place to test the safety and effectiveness of the Pfizer and Moderna vaccines in children 12 and older.

These are similar to the side effects for other vaccines (such as flu vaccines) and are a sign that the vaccine is working and that your body is building protection against the disease. Participants in each clinical study were monitored for eight weeks after they received the second dose to check for safety. In the past, other vaccines that produced bad reactions did so within six weeks of vaccination.

Are the vaccines safe and effective for people with my gender/ ethnicity/ health condition/ age?

Yes, they are safe and effective for people from different backgrounds. The Pfizer, Moderna, and J&J vaccines were tested among a wide group of participants, including people of color, different age groups, people with underlying health conditions, different genders, and people who previously had COVID-19 (Table 2). The data showed the Pfizer, Moderna, and J&J vaccines worked equally well and were equally safe across age groups, genders, and racial and ethnic groups. They also worked well and were safe for people with or without a wide variety of health conditions (Table 3).

Pregnant and nursing women were not included in the initial COVID-19 vaccine trials, so data on the safety of the vaccine in that population are limited. The Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists have stated that pregnant and nursing women may choose to get vaccinated after weighing the potential risks and benefits. The CDC recommends a discussion with your health care provider if you have questions.

Section 2 : Further Questions about the COVID-19 Vaccines

Are the COVID-19 vaccines safe and effective for people with diabetes?

Yes. All evidence from clinical trials suggests the vaccine is highly safe and effective in people with gestational diabetes, type 1 diabetes, type 2 diabetes, and severe diabetes complications.

  • For the Pfizer vaccine, 3,150 people with diabetes were tested in the clinical trials. The vaccine worked 94.7 percent of the time for this group.
  • For the Moderna vaccine, 2,858 people with diabetes were tested in the clinical trials. The vaccine worked 100 percent of the time for this group.
  • For the J&J vaccine, 3,389 people with diabetes were tested in the clinical trials. The vaccine worked 52.9 percent of the time for this group.

The CDC states that people with type 2 diabetes are at increased risk of severe illness, including hospitalizations and death, if they catch COVID-19. People with gestational diabetes or type 1 diabetes may also be at increased risk. Because of this, a group of scientists advising the CDC has recommended giving people with diabetes priority for the COVID-19 vaccine.

Are the COVID-19 vaccines safe for people with allergies?

Yes. The CDC recommends that people with a history of severe allergic reactions that are not related to vaccines or injectable medications—such as food, pet, environmental, or latex allergies—get vaccinated. People with a history of allergies to oral medications or a family history of severe allergic reactions may also get vaccinated. People who are allergic to a specific component of the mRNA vaccines, including polyethylene glycol (PEG) or a related compound called polysorbate, should not get the Pfizer or Moderna vaccines unless evaluated by an allergy-immunology specialist.

However, there are some cases where you should talk to your doctor before getting the vaccine. If you have had an immediate allergic reaction—even if it was not severe—to a vaccine or injectable therapy for another disease, ask your doctor if you should get a COVID-19 vaccine.

Are there other COVID-19 vaccines being tested?

Yes. There are 82 vaccines currently being tested in clinical trials around the world; as of April 2021, 23 had advanced to the final stages. A vaccine developed by AstraZeneca has been approved by India, the United Kingdom, and some other countries, but because the FDA must carefully review the data from each vaccine’s clinical trials before it can be approved, it is going to take some time before the AstraZeneca vaccine or others become available in the United States. 

I read a news story about some people potentially being harmed by a COVID-19 vaccine. Should I be concerned?

No. As COVID-19 vaccines become more broadly used by millions of people, news stories will surface that question whether an individual person or a small number of people were hurt by the vaccines. In many cases, the incidents described will turn out to be random chance, in which someone who was already going to come down with a bad health condition had, by coincidence, just received a COVID-19 vaccine.

In other cases, this could be due to a very rare reaction to the vaccines. For instance, anaphylaxis—a potentially life-threatening allergic reaction—is a very rare side effect that has occurred with other vaccines. Anaphylaxis after vaccination occurred for the Pfizer vaccine at a rate of 4.7 cases per 1 million doses administered, and for the Moderna vaccine at a rate of 2.5 cases per 1 million doses administered. The individuals who experienced anaphylaxis recovered and there were no fatalities. For comparison, the death rate in the United States for COVID-19 is about 1,500 per 1 million people.

Are COVID-19 vaccines tested for safety after the clinical trial is over?

Yes. The CDC and FDA continue to monitor vaccines for quality and safety after they have been approved for use in the general public. Besides ensuring continued safety, this allows the agencies to change and update recommendations as needed. For example, polio vaccination protocols were changed to increase effectiveness and safety in 1997.

The CDC and FDA maintain three systems for monitoring vaccine safety:

Do I have to pay to receive a COVID-19 vaccine?

No. Vaccine doses will be given to people living in the United States at no cost. However, vaccination providers can charge an administration fee for giving you the shot, which can be reimbursed by your insurance company or, if you’re uninsured, by the Health Resources and Services Administration’s Provider Relief Fund.

When will a COVID-19 vaccine become available to the general public?

In early 2021, there may not be enough vaccine doses available for all adults. Supplies will increase over time, and all adults should be able to get vaccinated later in 2021. Trials are ongoing for COVID-19 vaccines for children 12 to 16 and will not be available until the data clearly show they are safe and effective. Vaccines for younger children will come later. 

A committee of health experts is advising the CDC on how to equitably distribute the COVID-19 vaccine, and has recommended that the vaccine be offered first to health care workers, nursing home staff and residents, frontline and essential workers, and people 75 or older.

Considering the virus’s disproportionate impact on underserved communities, the National Academy of Sciences has recommended that state and local governments prioritize delivering the vaccine to communities of color, low-income communities, and Indigenous communities.

Who decides who gets the COVID-19 vaccines and when?

State and local leaders decide who gets the vaccine sooner, based on CDC guidelines. Different states, cities, and counties have different rollout plans in place; therefore, you should check your local government’s website for its distribution plan and further information on vaccine availability. The state of Ohio, for example, prioritizes those working in essential and frontline jobs, including hospital and grocery store workers.

Where will I need to go to get the vaccine?

There are already several thousand places across the country to get vaccinated, including doctors’ offices, retail pharmacies, hospitals, and health centers. Check your state government’s website for information on where the vaccine will be offered in your area.

What are the risks associated with not getting a COVID-19 vaccine?

If you choose not to get vaccinated, you are at risk of catching a potentially deadly disease and spreading it to people around you, including your loved ones. While COVID-19 causes mild symptoms in most people, some people of all ages get severe symptoms and even die.

People over 65 and people with certain health conditions are at higher risk of severe symptoms, but severe symptoms and death can occur in anyone. Some people who survived COVID-19 have experienced long-term symptoms over a number of weeks or months, which can include shortness of breath, a persistent cough, fatigue, difficulty with thinking and concentrating, an intermittent fever, or a loss of smell or taste.

Can I spread COVID-19 even after I get the vaccine?

This is still an open question. A vaccine helps prevent people from getting sick. People who are showing signs of sickness are believed to be more likely to spread the virus than people who are not showing signs of sickness. A COVID-19 vaccine therefore probably reduces the likelihood of spreading the disease for at least some people, but this is still being studied.

If you encounter someone with COVID-19, the vaccine does not prevent the virus from entering your body. Therefore, a vaccinated person can potentially still harbor a small amount of the virus in their nose, mouth, and other parts of the body that could infect other people before it is cleared by the immune system. However, your immune system will actively fight any virus that enters your body, and the vaccine will greatly aid your immune system in reducing the amount of virus in your body.

Since health experts consider it a possibility that a vaccinated person could spread COVID-19, it is best to be safe and continue with social distancing measures such as avoiding close contact with individuals living outside your household, avoiding touching your face, and washing your hands frequently and thoroughly.

Wearing a mask continues to be of the utmost importance. The CDC recommends non-medical disposable masks or cloth masks made of tightly woven material, ideally with two or more layers of fabric to filter the air you breathe. The mask should fit snugly around the nose, chin, and sides to prevent unfiltered air from escaping. Dr. Anthony Fauci has recommended that people double up on masks to increase their effectiveness.

How many people need to get vaccinated before the pandemic is no longer a threat?

Dr. Anthony Fauci has estimated that 70 to 90 percent of the US population will need to be immune, either by surviving an infection or by getting a vaccine. This estimate is based on how easily the virus is spread, but experts do not yet know the exact percentage of people who would need to get vaccinated to prevent further spread. For most infectious diseases, 50 to 90 percent of the population needs to be immune to stop it from spreading.

If I’m young and healthy, should I take the COVID-19 vaccine? Should I get vaccinated if I don’t have any risk factors?

Yes. Getting a vaccine is a much safer option to build protection against COVID-19 than developing immunity by contracting the disease. Although severe COVID-19 symptoms—including death—are more likely for certain people, they can happen to anyone, including healthy and young people.

Vaccination also reduces the likelihood of you spreading the illness to others in your household or social circle. Even if you do not have symptoms, you could give COVID-19 to someone who is more vulnerable to severe symptoms.

What about the recently discovered COVID-19 variants?

The virus that causes COVID-19, like any virus, will naturally change over time. Sometimes these changes can lead to a new strain or variant that behaves differently in people. As of April 2021, five new COVID-19 variants of concern have emerged: one was discovered in the United Kingdom, another in Brazil, another in South Africa, and another two in California. All five have been detected in the United States and are believed to spread much more easily than the original version of the virus that causes COVID-19 because they require a smaller amount of the virus and less exposure time to infect a healthy person. Health experts are closely monitoring the situation and recommend continued social distancing measures to prevent spread of the disease.

Are the vaccines effective against the recently discovered variants?

Yes, but a little less effective. Because of the way the immune system responds to the virus, most health experts believe the COVID-19 vaccines will work well in people with the new variants. Even if COVID-19 mutates to a point where the current vaccines are not able to protect people, Pfizer and Moderna used a method that will allow them to update their vaccines in a matter of weeks. Vaccine manufacturers are also testing whether booster shots would provide more protection from the variants.

Evidence is emerging that the variant from South Africa may be able to evade one of the immune system’s tools to fight the virus. Some vaccine trials in South Africa have also shown that the new variant has somewhat reduced the vaccines’ effectiveness, but they are generally still thought to be protective.

If I already had COVID-19, should I still get vaccinated?

Yes. Due to the severe health risks associated with COVID-19 and the fact that re-infection is possible after several months (though rare), you should be vaccinated even if you already had the disease. Experts do not yet know how long someone is protected from getting sick again after recovering from COVID-19; the immunity someone gains from having an infection varies from person to person. The Pfizer, Moderna, and J&J vaccines were shown to be safe for people who previously had COVID-19, but it is less clear how protective the vaccine is against future COVID-19 infections for this group.

How long should I wait to get vaccinated if I am recovering from COVID-19?

You should wait to be vaccinated until after you have recovered and are out of quarantine. The length of your recovery may depend on the severity of your symptoms; if you are unsure, consult your doctor.

What are the factors I should consider when making the decision whether to get the COVID-19 vaccine?

What is your risk of getting COVID-19?

  • How many people do you come into contact with each day?
  • Can you work at home?
  • Are you at increased risk for severe symptoms/death from COVID-19?

Your risk of spreading COVID-19

  • Are your loved ones at increased risk for severe symptoms/death?
  • How would you feel if you gave COVID-19 to a friend or loved one?
  • How many people do you come into contact with each day?
  • Could you spread the virus to neighbors or essential workers?

Quality and availability of the vaccine

  • Tested for safety and effectiveness
  • Up to 95 percent effective in clinical trials
  • Very few side effects
  • Tested in many types of people
  • Available without charge (or for a fee that can be reimbursed) at a nearby facility

The health and well-being of your community

  • To end the pandemic, a large percentage of people need to be vaccinated
Where can I get more information that I can trust about the COVID-19 vaccines?

COVID-19 (Coronavirus Disease): Vaccines” by the CDC. The CDC’s website contains lots of information on COVID-19, including eight things to know about the US vaccination program, what to expect at your vaccination, and frequently asked questions about vaccination.

Emergency Use Authorization for Vaccines Explained” by the FDA. This website details the steps taken by the FDA to make sure COVID-19 vaccines are safe and that they work.

Union of Concerned Scientists blog series on COVID-19. We especially recommend posts that examine the science of vaccine development, the complex scientific and ethical issues surrounding who gets the vaccine first, and the quandary of vaccine trials for African Americans.

Because vaccine distribution is controlled at the state and local level, we recommend you look to your state or county health department’s website to learn when and where you will be able to get vaccinated.

Table 1. Basic Facts about COVID-19 Vaccines

SOURCES: Briefing Materials on Pfizer, Moderna, and J&J vaccines from FDA’s Vaccine and Related Biological Products Advisory Committee.
Pfizer-BioNTech vaccineModerna vaccineJohnson & Johnson vaccine
For people 16 years and olderFor people 18 years and olderFor people 18 years and older
2 doses, 3 weeks apart2 doses, 1 month apart1 dose
44,000 participants30,400 participants43,000 participants
95% effective at preventing COVID-1994.5% effective at preventing COVID-1966.9% effective at preventing COVID-19

Table 2. Racial and Ethnic Demographics of Participants in COVID-19 Vaccine Clinical Trials

SOURCES: Briefing Materials on Pfizer, Moderna, and J&J vaccines from FDA’s Vaccine and Related Biological Products Advisory Committee.
Pfizer-BioNTech vaccineModerna vaccineJohnson & Johnson vaccine
African American3,929 people (9.8%)3,090 people (10.2%)8,515 people (19.4%)
Asian American1,763 people (4.4%)1,385 people (4.6%)1,430 people (3.3%)
Latino10,553 people (26.2%)6,234 people (20.5%)19,837 people (45.3%)
Native/Indigenous253 people (0.6%)230 people (0.8%)4,143 people (9.5%)
White33,006 people (81.9%)24,023 people (79.2%)25,696 people (58.7%)

Table 3. Other Demographics of Participants in COVID-19 Vaccine Clinical Trials

SOURCES: Briefing Materials on Pfizer, Moderna, and J&J vaccines from FDA’s Vaccine and Related Biological Products Advisory Committee.
Pfizer-BioNTech vaccineModerna vaccineJohnson & Johnson vaccine
Women19,901 people (49.4%)14,355 people (47.3%)19,722 people (45.0%)
Men20,376 people (50.6%)15,995 people (52.7%)24,053 people (54.9%)
65 years and older8,613 people (21.38%)7,520 people (24.8%)8,561 people (19.6%)
People with underlying health conditions18,592 people (46.2%)6,742 people (22.2%)217,858 people (40.8%)

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