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Babylon Health

COVID-19 Vaccine: All Your Questions Answered

This article was reviewed on June 21, 2022.

More and more countries around the world are approving COVID-19 vaccines to stop the pandemic – including the United States. But as the rollouts take place, many people find they have questions. For example, you may wonder whether the vaccines are safe, whether they are effective, or what the side effects of getting vaccinated might be.

The information in this article is designed to answer some of the most common questions and concerns. It is there to help you understand more about how the vaccines work, how they protect our bodies and to put your mind at ease when it comes to getting vaccinations for you and your family.


Q 1. Why is it important to get the Covid vaccine?

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Getting the COVID-19 vaccine is important to reduce your risk of getting and spreading the virus.

It’s commonly known that older people (60+ years) and people with chronic diseases like diabetes, kidney and heart disease are at risk to get seriously ill, and even die. It’s less well known that other groups can also be at risk, like pregnant women and even children.

We don’t yet understand why some people get very sick and some don’t. Even if you are young and in good health, it is important to be vaccinated to prevent you from becoming infected and spreading the disease to your family, friends and coworkers.

It is important to get vaccinated even if you have had COVID-19 infection. The vaccine gives you a stronger immune response than getting the actual disease, which means better prevention. Even if you have recovered from an infection, it is also possible to become infected with a different variant of the COVID-19 virus.

Q 2. How do the vaccines work?

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All Coronavirus vaccines work by teaching your immune system how to recognize and then attack the virus that causes COVID-19.

This ability is known as immunity. Immunity helps your body attack the virus when you have been exposed to COVID-19 and prevent the damage usually caused by the virus once it enters your body, preventing you from getting sick.

For many years, Biotech companies have developed vaccines by first creating a weakened or damaged virus, testing it in animals and then people. The first coronavirus vaccines approved by the FDA (made by pharmaceutical companies Pfizer/BioNTech and Moderna) are a type of new vaccine based on messenger RNA (mRNA). mRNA vaccines work by giving your body instructions to produce a harmless protein from the coronavirus. Your immune system will recognize this coronavirus protein and destroy the virus if you get infected with the real COVID-19 virus (called SARS-CoV-2).

Q 3. Can the shot give me coronavirus?

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No. Many people worry that the vaccine will give them the COVID-19 disease and make them sick. But none of the approved vaccines contain the actual virus itself.

Even though you can’t get COVID-19, there are some short term side effects that some people will get from the vaccine. Symptoms are self-limited, meaning they only last a few days, including aches and pains, fatigue (feeling really tired), and even fever.

The vaccines only contain selected (and safe) viral parts such as proteins from the virus. In the past 2 decades, we have discovered how the immune system works in detail. We know how our cells support the immune system, how to turn on the immune response, regulate it, and target it. Drug companies now can copy these virus proteins and use that material to create the vaccine itself. These proteins cannot replicate and cause the disease on their own, but they are recognized by our immune system as “foreign and dangerous”. When we are injected with this copied material, our immunity cells turn on the immune response and build antibodies to protect us and defend our bodies. Should we ever be infected after being vaccinated, these cells then remember how to fight the virus, and protect us rapidly.

Q 4. Are there side-effects from getting the vaccine?

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Yes, although many people do not experience side effects. However, other people do. These side effects are caused by the normal immune response the vaccines create in our bodies. Some of the most common side effects include:

  • Fatigue
  • Headache
  • Muscle aches

For some people, side effects may last through the first week after vaccination. However, most people experience side effects only for one or two days after getting the vaccine.

Side effects are more frequent following the second dose of the vaccine and are more likely to be experienced by younger, rather than older people. These symptoms can be treated with tylenol or motrin, rest, and fluids.
You are not contagious at all, but you may want to stay home and rest for a day or 2. Most people have little or no effects.

Q 5. Where can I be vaccinated?

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Each state has its own plan for distributing vaccines to the public. These plans are based on guidance from the Centers for Disease Control and Prevention (CDC). However, each state’s plan is slightly different. It is best to check your state health department website as most of the states have put their plans there. Some states also have opportunities to sign up for text or email alerts about vaccine distribution information.

To find a vaccine location near you:

You can also get a free ride to your vaccination appointment by contacting Lyft.

Q 6. Are the vaccines effective?

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All vaccines (including those for coronavirus) must pass through a number of strict healthcare tests to ensure that they are effective at preventing disease and safe to use.

These tests are called clinical trials. Specialists do these tests to check whether the vaccines are good at building immunity and that people who have had the vaccines are strongly protected against disease.

All the available COVID-19 vaccines have been tested in FDA approved clinical trials and found to be both safe and highly effective at preventing people from developing the illness.

Q 7. I had COVID-19 and I recovered. Am I immune, or do I need to get vaccinated?

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Yes. Healthcare experts believe that recovering from COVID-19 does offer some natural protection against getting sick again. This natural protection is called natural immunity.

However, they are not sure how long this protection lasts. People can become critically ill after reinfection, so it may not be enough to rely on natural immunity. Vaccination will help your body create a strong immune response to the virus that will offer effective protection.

As more information becomes available about both natural immunity and immunity produced by vaccines, the CDC will keep the public informed. Initial follow up studies do suggest that the immunity that results by receiving the vaccine is stronger than just getting the disease itself.

Q 8. How long until I am protected from Covid-19 after being vaccinated?

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Many people believe that they are protected from the virus the moment after they have received the vaccine. However, this is false.

It takes a few weeks for the body to build immunity after vaccination. That means that it is possible to be infected with COVID-19 just before or just after vaccination and still get sick. If this happens, it is because the vaccine has not had enough time to provide the body with protection.

Q 9. Can mRNA vaccines change my DNA?

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No. mRNA vaccines do not operate in the same place that DNA is located. The mRNA is active only in a part of the cell called the cytoplasm and DNA is located in the nucleus.

Also, mRNA is unstable and remains in the cell cytoplasm for only a limited time before it is naturally broken down by the body. Both of these factors mean that mRNA never enters the nucleus where the DNA is located so it can’t alter DNA.

Q 10. What You Should Know About the Possibility of COVID-19 Illness After Vaccination

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  • A small percentage of people fully vaccinated against COVID-19 will still develop COVID-19 illness

COVID-19 vaccines are effective. However, a small percentage of people who are fully vaccinated will still get COVID-19 if they are exposed to the virus that causes it. These are called “vaccine breakthrough cases.” While these vaccines are effective, no vaccine prevents illness 100% of the time. For any vaccine, there are breakthrough cases.

This means that while people who have been vaccinated are much less likely to get sick, it will still happen in some cases. It’s also possible that some fully vaccinated people might have infections, but not have symptoms (asymptomatic infections). Experts continue to study how common these cases are.

  • Other reasons why fully-vaccinated people might get COVID-19

It’s possible a person could be infected just before or just after vaccination and still get sick. It typically takes about 2 weeks for the body to build protection after vaccination, so a person could get sick if the vaccine has not had enough time to provide protection.

New variants of the virus that causes COVID-19 illness are spreading in the United States. Current data suggest that COVID-19 vaccines authorized for use in the United States offer protection against most variants. However, some variants might cause illness in some people after they are fully vaccinated.

  • If you get COVID-19 after vaccination, your symptoms might be less severe

There is some evidence that vaccination may make illness less severe in people who get vaccinated but still get sick. Despite this, some fully vaccinated people will still be hospitalized and die. However, fully vaccinated people are much less likely to be hospitalized or die than people with similar risk factors who are not vaccinated.

Large-scale clinical studies found that COVID-19 vaccination prevented most people from getting COVID-19. Research also provides growing evidence that mRNA COVID-19 vaccines (Pfizer-BioNTech, Moderna) offer similar protection in real-world conditions.

Q 11. Will I test positive for Covid-19 on a viral test after getting the vaccine?

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No. None of the vaccines can cause you to test positive on viral tests, which are used to see if you have a current infection. However, vaccines can cause you to test positive on antibody tests, which is a good thing. After vaccination, your body will develop an immune response to the vaccine – your immune cells will produce the antibodies it needs to fight a COVID-19 infection. Following your vaccination, positive blood tests for antibodies will indicate your cells have learned how to make the antibodies and you now have some level of protection against the virus. However, if you test positive on an antibody test after vaccination, it means, simply, that the vaccine has been helpful at preparing your body for a possible infection. Experts now are studying antibody levels, and how long they remain high to understand how strong the immunity is and how long it will last.

Q 12. What different types of vaccines are available?

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There are a number of different vaccine types currently being tested. They all work in a slightly different way. Some work by introducing artificial copies of messenger genetic material that matches the spoke proteins from the virus (nothing from the live virus itself) into our bodies. This genetic material is the “messenger” that gives our bodies instructions for how to make specific proteins found on the virus. Recognizing these proteins means our immune cells will recognize and kill any actual COVID-19 viruses.

Other types of vaccines include these harmless virus proteins directly.

A final type of vaccine contains a different weakened virus (not the COVID-19 virus) that contains genetic material that matches material from the actual COVID-19 virus. As before, this weakened non-COVID-19 virus gives our cells instructions to make proteins that are also found on COVID-19. By training our bodies to recognize and fight these proteins, our bodies are able to quickly recognize and fight an actual COVID-19 infection.

It is important to note that none of the vaccines can give you COVID-19. None of the vaccines actually contain the COVID-19 virus itself.

Q 13. Who should not get the Covid-19 vaccine?

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The more people who are vaccinated, the better. However, there are a few small groups of people who should not get the vaccine. Other high-risk patients should consult with their doctor or healthcare provider before getting vaccinated. If you fall into any of the categories I’m going to state, you should consult with your doctor before getting vaccinated.

  • Anyone with a previous severe or immediate allergic reaction to a COVID-19 mRNA vaccine dose, a vaccine component, or polysorbate
  • People currently isolating or experiencing symptoms that could be coronavirus
  • Individuals with a history of severe or immediate allergic reaction to any vaccine or injectable medication
  • People with certain immune-compromising conditions
    • If you have questions about specific conditions, please seek guidance from your Babylon healthcare provider
  • People on anticoagulants

Children 6 months and older can now get a free COVID-19 shot!

Q 14. Once I have been vaccinated, do I still have to follow lockdown restrictions and social distancing?

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You should continue to follow CDC recommendations on isolation, quarantine, and social distancing if you are not up to date on your COVID-19 vaccine.
You are considered up to date on your COVID-19 vaccine if you have received all the recommended doses in the primary series as well as booster doses when recommended.

If you have a condition or are taking medications that weaken your immune system, you may NOT be protected even if you are up to date on your COVID-19 vaccine. You should continue to take all precautions recommended for unvaccinated people until advised otherwise by your healthcare provider.

Q 15. Can I get the vaccine if I have an egg allergy?

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People with an egg allergy can't have some vaccines like the flu vaccine because egg protein is used in the manufacturing process. The manufacturing process for the COVID vaccine is different and doesn’t use egg protein.

None of the COVID-19 vaccines are thought to present any danger or risk to people who are allergic to certain foods, such as eggs and gelatin. Allergies to other materials like latex, pet fur, pollen, insect bites and medications are also not thought to be a problem.

However, it is wise to tell your healthcare provider if you have a history of allergic reactions prior to getting vaccinated. In this case, you may be watched and monitored for 30 minutes after your shot (rather than the standard 15 minutes).

You should not receive a COVID-19 vaccination if you

  • have had a severe allergic reaction after a previous dose of a COVID-19 vaccine
  • have a known allergy to a component of the vaccines such as polyethylene glycol (PEG) or polysorbate
  • for those receiving Johnson & Johnson / Janssen COVID-19 vaccine: developed thrombosis with thrombocytopenia syndrome (TTS) after receiving an adenovirus based COVID-19 vaccine such as Johnson & Johnson / Janssen vaccine

If you have had an allergic reaction to another type of vaccine or injected medication in the past, you should talk to your doctor about the risks.

The information provided is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Seek the advice of a doctor with any questions you may have regarding a medical condition. Never delay seeking or disregard professional medical advice because of something you have read here.