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Frequently Asked Questions About the COVID-19 Vaccine

Click below to get answers to common questions about the COVID-19 vaccine. 

About the Vaccine


Are the vaccines safe?

  • There are no reported serious safety concerns from either vaccine. All approved vaccines will have gone through extensive clinical trials. The vaccine’s safety and efficacy will be reviewed by two panels of independent experts at the FDA.
  • While the vaccine did go through the clinical trial process quickly, it was tested on thousands of people just like every other vaccine or treatment that needs to be approved by the FDA. The shorter timeframe for vaccine development was achieved by reducing the time between each phase of the clinical trials.

What are the long-term side effects of the vaccine?

  • The vaccine has been tested on tens of thousands of people in initial clinical trials. No serious safety concerns were reported in these trials. However, more monitoring is needed to better understand if there are any long term side effects beyond the timeframe of the clinical trials. Ongoing safety monitoring through existing programs will continue to address safety concerns with the vaccine in real-time. The programs include the Vaccine Safety Datalink, Clinical Safety Assessment project, Vaccine Adverse Event Reporting Systems and new monitoring systems such as the V-SAFE program and the National Healthcare Safety Network.

Will the protection the vaccine offers last?

  • At this time, we don’t know how long the protection from the vaccine will last. The initial studies have shown the vaccine to provide protection from COVID-19 infection for the duration of the trials. There will be ongoing monitoring of the vaccination.

Does the COVID-19 vaccine provide protection from the new COVID-19 variant from the UK?

  • Yes, researchers expect the COVID-19 vaccine will protect people against the new strain, and studies are underway to confirm this. The new strain, known as B.1.1.7 (B-117), was first discovered circulating widely in England during November and December of 2020. It has now been confirmed in Wisconsin and other states. Epidemiologic and modeling studies indicate that the B-117 strain spreads more rapidly and easily than the original strain of SARS-CoV-2 (the virus causing COVID-19). The new strain does not cause more severe illness or increased risk of death. However, it could lead to more hospitalizations and deaths by infecting more people. Mask use, social distancing and other public health measures are very important to control the spread of the B-117 strain.

Does the COVID-19 vaccine contain a microchip that can track you?

  • No. There is no microchip or tracking device in the vaccine.

Does the COVID-19 vaccine alter your DNA?

  • No, mRNA vaccines do not alter DNA. The biochemistry of DNA and RNA is well-understood, and mRNA vaccines never enter the part of your cell that house the DNA. There are only a few copies of the vaccine mRNA in the cell, and the mRNA is broken down quickly to harmless molecules. Learn more about mRNA vaccines here.

Does the vaccine cause infertility?

  • There is no evidence that the COVID-19 vaccine causes infertility. In fact, no safety concerns were demonstrated in rats that received Moderna COVID-19 vaccine prior to or during gestation in terms of female reproduction, fetal/embryonal development or postnatal development. The rumors about infertility were fueled by an article published by a blog called Health and Money News, which falsely claimed that Pfizer’s vaccine contained ingredients capable of “training the female body to attack” a protein that plays a crucial role in the development of the placenta. Based on current knowledge, experts believe that mRNA vaccines are unlikely to pose a risk to the pregnant person or the fetus because mRNA vaccines are not live vaccines. The mRNA in the vaccine is degraded quickly by normal cellular processes and does not enter the nucleus of the cell. Learn more from this New York Times article.

Is natural infection from COVID-19 better than an actual vaccine?

  • No. Natural infection leads to death in about 1% of infected people, and it has caused more than 300,000 deaths in the U.S. during 2020. The COVID-19 vaccine provides almost full protection against illness without any serious safety concerns. The strength and duration of protection after natural infection is not known, and you should receive the COVID-19 vaccine even if you had a prior infection.

Does the vaccine give you COVID-19?

  • No. The vaccine cannot cause COVID-19. The vaccine is manufactured without live viruses, and the mRNA vaccine generates a single protein that triggers the immune response.

What is the cost of the vaccine?

  • Vaccines will be provided to patients at no cost. Your insurance may be billed for a vaccine administration fee, but all private/public insurance will cover this cost. If you are uninsured, the cost will be covered by the Health Resources and Services Administration’s Provider Relief Fund.

What does the expiration date mean on the vaccination record card I received after the COVID-19 vaccine?

  • This date refers to the expiration of the vial of vaccine. It is not when the protection the vaccine provides ends. We do not yet know how long the vaccine protection lasts.

Do I need my ID to get the vaccine?

  • You do not need an ID to receive the COVID-19 vaccine, nor can you be turned away for not having an ID. However, you may be asked to provide an ID to confirm your appointment. If you are an undocumented immigrant, you can get vaccinated.

Your Personal Health and the Vaccine

Do I have to continue wearing a mask after I get the vaccine?

  • Yes, you should continue to wear PPE until the CDC and State of Wisconsin guidelines change. Initial studies have shown the vaccine to be effective at preventing illness of the vaccine recipient, but there is still more to learn about if the vaccine protects individuals from potentially spreading illness.

If I’ve had COVID-19 already, do I still need the vaccine?

  • Patients with documented acute SARS-CoV-2 infection in the preceding 90 days may choose to delay vaccination until near the end of the 90-day period in order to facilitate vaccination of others who remain susceptible to infection. However, all individuals should receive COVID-19 vaccine even if they have had the infection.

If I’ve received passive antibody therapy, do I need to wait to receive the COVID-19 vaccine?

  • If you have received passive antibody therapy, you should wait 90 days since your last treatment to receive the COVID-19 vaccine.

How long do I have to stay after I get the COVID-19 vaccine?

  • CDC currently recommends the following:
    • Persons with a history of anaphylaxis due to any cause or history of immediate allergic reaction of any severity to a vaccine or injectable therapy: 30 minutes
    • All other persons: 15 minutes

Should I get the COVID-19 vaccine if I recently received a different vaccine?

  • Given the lack of data on the safety and efficacy of COVID-19 vaccines administered simultaneously with other vaccines, the CDC recommends that the COVID-19 vaccine not be given with other vaccines at this time. You should wait 14 days after receiving another vaccine to get the COVID-19 vaccine. You should wait 14 days after receiving the COVID-19 vaccine before receiving another vaccine.

Is the vaccine safe for pregnant women?

  • At this time, there is no safety data for pregnant or breastfeeding women.

If I have underlying health issues (co-morbidities), can I still get the vaccine?

  • Clinical trials demonstrated similar safety and efficacy profiles in persons with some underlying medical conditions, including those that place them at increased risk for severe COVID-19, compared to persons without comorbidities. However, you should talk to your doctor before receiving the COVID-19 vaccine because there are special precautions for certain individuals.

Should I still get the vaccine if I had a positive antibody test for the virus?

  • Yes. A positive antibody test means you were previously infected with SARS-CoV-2 (virus that causes COVID-19), but it does not mean you are protected from getting reinfected. Vaccination is safe and recommended for people with and without prior infection with SARS-CoV-2.

How does COVID-19 vaccination affect COVID-19 testing?

  • If you previously received a COVID-19 vaccination, it will not affect the results of COVID-19 viral tests including nucleic acid amplification or antigen tests.

Do I need to get the same vaccine for my second dose as I did for my first dose?

  • Yes. Both mRNA COVID-19 vaccines (Pfizer and Moderna) require two doses to be complete. These mRNA COVID-19 vaccines are not interchangeable with each other or with other COVID-19 vaccine products. The safety and efficacy of a mixed-product series has not been evaluated. Both doses of the series should be completed with the same product. The Janssen (Johnson & Johnson) COVID-19 vaccine is a single dose product.

How long do I have to stay after I get the COVID-19 vaccine?

  • CDC currently recommends the following: Persons with a history of anaphylaxis (due to any cause): 30 minutes and All other persons: 15 minutes.

Is there anything I need to know about getting my second dose of the vaccine?

  • When you come in for your second COVID-19 vaccine appointment, make sure to bring your COVID-19 vaccination card. You should also make sure you are receiving the same vaccine you received during the first appointment. Some people experience more severe side effects following the second dose of the vaccine.

Will I need to stop any medications prior to vaccination?

  • No. There are currently no medications that have been listed as being contraindicated in individuals receiving the COVID-19 vaccines.

Should I take an antihistamine medication like Benadryl or Claritin prior to receiving the COVID-19 vaccine to prevent an allergic reaction from happening?

  • No. According to the CDC, taking an antihistamine prior to receiving the vaccine could mask the signs of a reaction and delay treatment. Antihistamines are not recommended prior to getting the vaccine. Antihistamines can be taken after onset of an allergic reaction to relieve symptoms of itching.

Should I take medications such as Tylenol or Ibuprofen before my COVID-19 vaccine?

  • Medicating before vaccination with pain relievers or fever reducers is usually not needed for any vaccine. With the COVID-19 vaccine, there have been some reports that taking NSAIDs such as ibuprofen or naproxen before vaccination will interfere with immune response. This has not been confirmed with studies. However, because of the lack of studies, the recommendation at this time is avoid NSAIDS (such as ibuprofen or naproxen) immediately before COVID-19 vaccination unless instructed otherwise by your provider. You may take medications such as acetaminophen or NSAIDs after your vaccination for symptom relief if needed. If you develop side effects like muscle aches, headache or fever, you can self-medicate like you normally would after a vaccination. If you have questions about a NSAID that you were prescribed or recommended to take regularly such as aspirin, please talk with your provider for guidance.

Are we conducting antibody testing after COVID-19 vaccination?

  • At this time, antibody testing is not currently recommended to assess for immunity to COVID-19 following COVID-19 vaccination or to assess the need for vaccination in an unvaccinated person. Based on clinician assessment, if evidence of immunity is needed for medical reasons, a provider may decide to request antibody testing to determine if natural immunity or vaccine-induced antibodies are present.

About the Pfizer COVID-19 Vaccine


Is the vaccine effective?

  • The Pfizer COVID-19 vaccine is 95% effective against symptomatic COVID-19. Protection is high even in older adults and people with chronic diseases. There is some evidence the vaccine also protects against severe COVID-19. Protection continues at a high level for at least 3-4 months. We do not yet know if protection will decline over time or if a booster dose will be needed.

What do we know about long-term safety after vaccination?

  • Safety was carefully assessed in the clinical trial that enrolled over 40,000 people. No safety concerns were found during 8 weeks after completing vaccination, providing a high level of confidence in vaccine safety. It is possible that a rare vaccine-related problem could occur with longer follow-up in larger groups, and there are several monitoring systems in place to make sure any safety issues are quickly found and investigated.

Can the vaccine cause serious allergic reactions?

  • There have been reports of rare, but serious allergic reactions occurring immediately after receiving the Pfizer vaccine. These are currently being investigated. CDC currently recommends that people with a past history of severe allergic reaction after vaccination or injectable medication should talk to their doctor before getting vaccinated with the Pfizer vaccine. This includes allergic reactions to polyethylene glycol or polysorbate. If you have allergies you are concerned about, talk to your doctor.

Should I expect any side effects after vaccination?

  • Yes. Pain at the injection site is common and many people develop symptoms such as fatigue, headache, chills and muscle aches. These are mild to moderate in most people and typically resolve after 1-2 days. Lymph nodes may also become swollen and tender on the same side as the injection. These side effects occur because the immune system is responding normally to the vaccine. In general, these side effects are more severe after the second dose, and they may be less severe in older adults.

How long should I wait between receiving dose one and two of my Pfizer COVID-19 vaccine?

  • The Pfizer COVID-19 vaccine should be given three weeks (21 days) apart. The second dose should be administered as close to three weeks as possible, but it can be given up to six weeks apart if needed. At Marshfield Clinic Health System, we are scheduling second dose appointments as we are scheduling first dose appointments with the correct time in between doses.

Can I get COVID-19 from the vaccine?

  • The Pfizer and Moderna vaccines use only a gene from the virus. These vaccines cannot cause COVID-19.

How does the vaccine work?

  • The COVID-19 vaccine uses mRNA as assembly instructions to tell your cells how to make a part of the virus, triggering an immune response. The mRNA provides instructions to make a single protein, thus it cannot create a living virus or cause COVID-19. The mRNA never enters the part of your cell that houses DNA, so it also cannot alter your DNA. mRNA vaccines have been studied for the past two decades and have undergone clinical trials for other infectious diseases including zika, influenza and rabies. Over that time, this process has been proven to be safe in these other clinical trials. Learn more about mRNA vaccines here.

About the Moderna COVID-19 Vaccine


Is the vaccine effective?

  • The Moderna COVID-19 vaccine is 94% effective against symptomatic COVID-19. Protection is high even in older adults and people with chronic diseases. There is some evidence the vaccine also protects against severe COVID-19. Protection continues at a high level for at least 3-4 months. We do not yet know if protection will decline over time or if a booster dose will be needed.

What do we know about long-term safety after vaccination?

  • Safety was carefully assessed in the clinical trial that enrolled over 30,000 people. No safety concerns were found during 8 weeks after completing vaccination, providing a high level of confidence in vaccine safety. It is possible that a rare vaccine-related problem could occur with longer follow-up in larger groups, and there are several monitoring systems in place to make sure any safety issues are quickly found and investigated.

Can the vaccine cause serious allergic reactions?

  • There have been reports of rare, but serious allergic reactions occurring immediately after receiving the Pfizer vaccine. This has not been reported for the Moderna vaccine, but rare allergic reactions are possible with any vaccine. If you have allergies you are concerned about, talk to your doctor.

Should I expect any side effects after vaccination?

  • Yes. Pain at the injection site is common and many people develop symptoms such as fatigue, headache, chills and muscle aches. These are mild to moderate in most people and typically resolve after 1-2 days. Lymph nodes may also become swollen and tender on the same side as the injection. These side effects occur because the immune system is responding normally to the vaccine. In general, these side effects are more severe after the second dose, and they may be less severe in older adults.

How long should I wait between receiving dose one and two of my Moderna COVID-19 vaccine?

  • The Moderna COVID-19 vaccine should be given four weeks (28 days) apart. The second dose should be administered as close to four weeks as possible, but it can be given up to six weeks apart if needed. At Marshfield Clinic Health System, we are scheduling second dose appointments as we are scheduling first dose appointments with the correct time in between doses. Please make sure you are scheduled at 28 days from your first dose if you received the Moderna vaccine.

What are the ingredients in the vaccine?

  • The vaccine is manufactured without any human or animal cells, including embryonic stem cells. No live virus is used for vaccine production.
  • Ingredients include: mRNA, lipids (including polyethylene glycol), cholesterol, potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate and sucrose.

Can I get COVID-19 from the vaccine?

  • The Pfizer and Moderna vaccines use only a gene from the virus. These vaccines cannot cause COVID-19.

How does the vaccine work?

  • The COVID-19 vaccine uses mRNA as assembly instructions to tell your cells how to make a part of the virus, triggering an immune response. The mRNA provides instructions to make a single protein, thus it cannot create a living virus or cause COVID-19. The mRNA never enters the part of your cell that houses DNA, so it also cannot alter your DNA. mRNA vaccines have been studied for the past two decades and have undergone clinical trials for other infectious diseases including zika, influenza and rabies. Over that time, this process has been proven to be safe in these other clinical trials. Learn more about mRNA vaccines here.

About the Janssen (Johnson & Johnson) Vaccine


Is the vaccine effective?

  • The Johnson and Johnson COVID-19 vaccine is 66% effective against symptomatic COVID-19. Protection is high even in older adults and people with chronic diseases. The Janssen (Johnson & Johnson) COVID-19 vaccine is 85% effective in preventing severe COVID-19. Protection continues at a high level for at least 3-4 months. We do not yet know if protection will decline over time or if a booster dose will be needed.

How many doses do I need for the Janssen (Johnson & Johnson) COVID-19 vaccine?

  • The Janssen (Johnson & Johnson) COVID-19 vaccine is a single dose vaccine.

What do we know about long-term safety after vaccination?

  • Safety was carefully assessed in the clinical trial that enrolled more than 20,000 people. No safety concerns were found during 8 weeks after completing vaccination, providing a high level of confidence in vaccine safety. It is possible that a rare vaccine-related problem could occur with longer follow-up in larger groups, and there are several monitoring systems in place to make sure any safety issues are quickly found and investigated.

Can the vaccine cause serious allergic reactions?

  • Serious allergic reactions have not been reported for the Janssen (Johnson & Johnson) vaccine, but rare allergic reactions are possible with any vaccine. If you have allergies you are concerned about, talk to your doctor.

Should I expect any side effects after vaccination?

  • Yes. Pain at the injection site is common and many people develop symptoms such as fatigue, headache, chills and muscle aches. These are mild to moderate in most people and typically resolve after 1-2 days. Lymph nodes may also become swollen and tender on the same side as the injection. These side effects occur because the immune system is responding normally to the vaccine.

Can I get COVID-19 from the vaccine?

  • The Janssen (Johnson & Johnson) vaccine is a viral vector vaccine. Viral vectors cannot cause COVID-19 infection because it uses a modified version of a different, harmless virus to provide the protection.

How does the vaccine work?

  • The Janssen (Johnson & Johnson) COVID-19 vaccine is a viral vector vaccine. It uses a modified version of a different virus to deliver instructions using genetic material to the cells. This modified version is called a vector. Viral vector vaccines have been studied since the 1970s and have undergone clinical trials for other infectious diseases including Ebola. The viral vector never enters the part of your cell that houses DNA, so it also cannot alter your DNA.

Does the Janssen COVID-19 vaccine contain cells from aborted fetuses?

  • The Janssen COVID-19 vaccine does not contain any cells from aborted fetuses. However, Janssen did use fetal cell lines in the development and production of their COVID-19 vaccine. These specific fetal cell lines were reproduced from retinal cells that were taken from an aborted fetus in 1985. The Catholic Church, Southern Baptist Ethics & Religious Liberty Commission and the U.S. Conference of Catholic Bishops believe it is morally acceptable to receive a COVID-19 vaccine that requires fetal cell lines for production or manufacture. The U.S. Conference of Catholic Bishops has stated, “Given the urgency of this crisis, the lack of available alternative vaccines, and the fact that the connection between an abortion that occurred decades ago and receiving a vaccine produced today is remote, inoculation with the new COVID-19 vaccines in these circumstances can be morally justified.” Individuals are encouraged to discuss this issue with their faith leader or an expert of bioethics. With the lack of vaccine supply, it may be difficult to choose a specific COVID-19 vaccine for some time. For more information on this topic, go here.

What are the ingredients in the Janssen COVID-19 vaccine?

  • The ingredients include recombinant, replication-incompetent adenovirus type 26 expressing the SARS-CoV-2 spike protein, citric acid monohydrate, trisodium citrate dihydrate, ethanol, 2-hydroxypropyl-β-cyclodextrin (HBCD), polysorbate-80 and sodium chloride.

COVID-19 vaccine availability


Is a COVID-19 vaccine available?

  • As of Dec. 18, 2020, the Pfizer COVID-19 vaccine is available at several locations throughout the Health System. Pfizer was approved by the FDA for an Emergency Use Authorization for its COVID-19 vaccine on December 11, 2020. As of Jan. 5, 2020, the Moderna COVID-19 vaccine is available at limited locations throughout the Health System. Moderna was approved by the FDA for an Emergency Use Authorization for its COVID-19 vaccine on Dec. 18, 2020. As of March 1, 2021, the Janssen (Johnson & Johnson) COVID-19 vaccine is not available at Marshfield Clinic Health System. The Janssen (Johnson & Johnson) COVID-19 was approved by the FDA for an Emergency Use Authorization for its COVID-19 vaccine on Feb. 27, 2021.
  • There are several other vaccines undergoing clinical trials.

Will there be enough vaccine for individuals when they need their second dose?

  • Yes. The State of Wisconsin has the second dose set aside for the individuals that received their first dose with Marshfield Clinic Health System.

How do I get the COVID-19 vaccine through Marshfield Clinic Health System?

  • You can get the vaccine several ways through the Health System. Learn more about each option and how these options differ here. The options include:
    • Self-scheduling online
    • Walk-in clinics
    • Completing a form to request an appointment
    • Calling to request an appointment

Who is eligible for the COVID-19 vaccine?

  • All individuals age 16 and older are eligible for the COVID-19 vaccine. Individuals age 16 and 17 are only eligible to receive the Pfizer COVID-19 vaccine.

How much vaccine is the Health System receiving each week?

  • We are actively receiving a supply of the COVID-19 vaccine on a weekly basis from the Wisconsin Department of Health Services. Learn more here.

Looking for more information on COVID-19?

The situation is changing daily, and we regularly update our COVID-19 hub with the recommendations, MCHS updates and key resources you need to protect you and your family.


  Click here  


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