Texas Tech University

COVID-19 Vaccine Q&A

Updated January 14, 2022

Q&A : COVID-19 Vaccines

Q&A : COVID-19 Vaccines

  1. Are the vaccines safe?
    • Yes. The benefits of vaccination outweigh the risks for the vast majority of adults. The Pfizer and Moderna vaccines were made using RNA technology that was developed nearly 20 years ago. The Janssen / Johnson & Johnson (J&J) vaccine was made using inactivated adenovirus vector technology previously used to successfully create a vaccine against Ebola virus.  The vaccine trials included thousands of teenagers and adults of diverse ages and ethnicities and monitored them closely for months. The goal of vaccination is first to avoid illness (especially hospitalization and death due to COVID-19) and second to avoid spreading COVID-19 to others.
    • After 8 months of use under emergency authorization, the FDA granted full approval to the Pfizer-BioNTech COVID vaccine on 8/23/21. 
    • The American College Health Association advises college students to schedule their COVID vaccine as soon as possible.
    • From April 13th -  23rd, the FDA paused vaccination with the Janssen / Johnson & Johnson vaccine for further review due to case reports of low platelet counts and blood clots in a large vein in the brain. At the time, there were 6 cases in the 6.8 million doses administered in the U.S. These rare side effects are not reported with use of the Pfizer or Moderna vaccines. Signs of a blood clot include: severe headache, severe abdominal pain, unexpected leg pain, chest pain, or unexplained shortness of breath within 3 weeks of vaccination. On July 12th, the FDA updated added a warning of the risk of Guillain-Barre syndrome after vaccination with the Johnson & Johnson vaccine. Guillain-Barre syndrome is a rare auto-immune disorder involving numbness, tingling, and weakness from nerve destruction. About 3000 – 6000 cases are diagnosed every year in the U.S., often after viral infections such as the common cold or influenza. There were 100 cases of the syndrome in the 12.8 million vaccine doses given, typically in men age 50 and older. Seek medical attention immediately if experiencing any of these rare side effects. The Advisory Council on Immunization Practices, CDC, and the FDA agreed to resume use of the vaccine as the risk of blood clots and low platelet counts and Guillain-Barre syndrome are very low. The benefits of vaccination outweigh the risks.
    • The CDC prefers mRNA vaccines over the Johnson & Johnson vaccine for safety and efficacy reasons. 
    • Those with compromised immune systems are at high risk of severe outcomes if infected with COVID-19. A primary vaccine series and a booster are advised. 
        • On August 13th, the CDC and Advisory Council for Immunization Practices approved a 3rd dose of vaccine for those with “moderate to severe” immune suppression (mRNA vaccine to be administered at least 28 days after the 2nd dose). Examples of people in this category include organ transplant recipients, cancer patients, patients requiring immune-suppressing medications, and patients with HIV infection or AIDS.
      • 3rd dose of Pfizer vaccine (at least 5 months after completion of a 2 dose series): is advised for all people age 12 and older. If choosing a Moderna vaccine instead, then a 3rd dose of Moderna is advised by the FDA for all adults age 18 and older.
      • If you received a Johnson & Johnson vaccine, then a 2nd dose is advised by the FDA at least 2 months after the initial dose for all adults. 
    • Since the Pfizer and Moderna vaccine is made of mRNA, it cannot enter the nucleus of the cell or interfere with the DNA of the person receiving it. The J&J vaccine's genetic information does not incorporate into the DNA of the person receiving it.
    • The vaccines do not affect fertility. Some participants in the vaccine trials became pregnant shortly after vaccination.  Fully vaccinated individuals have achieved pregnancy.
    • There is a small risk of inflammation of the heart (myocarditis, pericarditis) associated with the mRNA vaccines, typically in males aged 12 – 29. These cases are mild and can occur after the 2nd dose. Symptoms include chest pain, shortness of breath, and racing heart/palpitations. Actual COVID-19 infection can cause significant heart damage and heart failure. The benefits of vaccination outweigh the small risk of heart inflammation. 
  1. Are the vaccines effective?
    1. Yes. By taking an available mRNA COVID-19 vaccine as scheduled in the 2-dose series, efficacy is nearly 95%. This level of protection requires 2 weeks after the 2nd dose. This is an excellent result and is close to the efficacy of the measles vaccine in preventing measles. A single dose of the J&J vaccine is 72% effective in the United States and 85% effective in preventing severe COVID disease at least 2 weeks after vaccination. We currently do not know the long-term efficacy of the vaccines years from now. Recent data indicate decreased efficacy against the highly infectious delta variant. However, vaccination is still advised, especially to reduce the risk of severe disease and hospitalization.
  2. Currently, who should receive a COVID-19 vaccine?
    • All adults: The Texas Department of Health and Human Services expanded vaccination to all adults on March 29th.  
    • Children age 5 through teenagers: are eligible for the Pfizer vaccine. Teenagers age 18 and older may receive any of the approved vaccines.
    • Anyone with a history of a severe reaction to any vaccine should be monitored for 30 minutes after receiving the COVID-19 vaccine.
  3. What are common side effects of the COVID-19 vaccine?
    • Details on potential side effects and treatment may be accessed at: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html
    • Some people may experience post-vaccination symptoms of feeling dizzy or light-headed within 15 minutes of receiving the vaccine. You will be monitored closely for at least 15 minutes after receiving the injection.
    • Soreness at the injection site, low grade fever and chills, fatigue, headache, and muscle aches may occur for up to 3 days after the injection, with most of these side effects typically occurring the day after vaccination. A stronger side effect response may be experienced after the 2nd dose of an mRNA vaccine.     
  4. Who should NOT receive a COVID-19 vaccine?
    • For people with history of an immediate reaction to any mRNA vaccines, polysorbate, or polyethylene glycol, consultation with an Allergy/Immunology specialist is advised before vaccination
      • Allergy to polysorbate is now considered a precaution, not a contra-indication, to receiving an mRNA vaccine. If you are allergic to polysorbate, polyethylene glycol, miralax, or colonoscopy preparation solution, then do not take the J&J vaccine. Please consult with a physician if there are questions or concerns.
    • If someone had anaphylaxis (confusion, trouble breathing, wheezing, low blood pressure, itching, swelling of the face and tongue, vomiting, and/or diarrhea) within 30 minutes of the first dose of an mRNA COVID-19 vaccine, then the second dose should not be given.
    • If you are still recovering from COVID, it is estimated that you are immune from re-infection for at least 3 months. Do not obtain a vaccine while still feeling sick from the original COVID infection.
    • If you had COVID in the last 3 months and received treatment with monoclonal antibodies or convalescent serum from donors, then wait at least 90 days from time of treatment.
    • The vaccines do not contain latex or egg and are safe for people with these allergies.
    • The vaccines do not contain fetal tissue.
    • The vaccines do not contain metals or microelectronics.
    • There are no documented cases of Guillain-Barre syndrome following vaccination with the Pfizer or Moderna mRNA vaccines.
    • Anyone with a history of a severe reaction to any vaccine should be monitored for 30 minutes after receiving the COVID-19 vaccine.
  5. Do I need a COVID-19 test before the vaccine?
    • No. If you are otherwise feeling well and had no recent high risk exposure to someone infected in the last 14 days, then there is no need for a test.
      After vaccination, there is no need for an antibody test to confirm immunity.
  6. Do I need a pregnancy test before the vaccine? 
    • No. Vaccine safety is being studied in large populations of pregnant women. Pregnant women who are infected with COVID-19 are at increased risk of severe outcomes to themselves and to their developing babies. The vaccine is not a “live” virus, so it will not infect the developing baby or enter the breast milk. Protective antibodies made by the mother against the virus are able to cross the placenta and offer the baby some immune protection. If there are questions and concerns, please discuss these with your healthcare provider.
    • For those who are lactating/breast-feeding, there is no need to stop.
    • For those planning pregnancy, there is no need to avoid or delay plans.
  7. Within the last 14 days, I was exposed to COVID by close contact with someone who is infected. Will the vaccine prevent post-exposure infection?
    • No. The vaccine will not prevent infection from the recent high-risk exposure since it takes days to weeks to respond effectively to the vaccine. Please quarantine at home and monitor for symptoms to reduce the risk of infecting others. Please get tested upon learning of the exposure and again 5-7 days after the exposure or if developing symptoms. If there are no signs or symptoms of infection in the 14 days after exposure, then you can proceed with vaccination. 
  8. Can I receive the COVID-19 vaccine at the same time as a flu vaccine or other vaccine?
    1. Yes.
  9. I missed by 2nd dose of the Pfizer or Moderna vaccine. Do I need to repeat the first dose?
    • No. There is a “grace” period from the time it was due. Please obtain the 2nd dose as soon as possible from the time it was due, preferably no later than 6 weeks from the time of the first dose.
  10. I received my 2 dose series of mRNA vaccine or single dose of J&J vaccine. Can I go back to my normal life again?
    • Not yet but hopefully soon. The vaccines are highly effective but there is no 100% guarantee that you will not get COVID-19 after vaccination. Experts indicate that until at least 70% of the population is immune, the virus can still spread in an uncontrolled manner. The CDC advises to continue strategies to keep you and your loved ones, friends, and co-workers healthy by wearing a mask, avoiding crowds, and keeping a 6-foot distance until fully vaccinated. Stay home when not feeling well and wash hands routinely. If we all do our part, then the pandemic will end sooner rather than later.


CDC's Guidance for Institutions of Higher Education. Updated 11/4/21. https://www.cdc.gov/coronavirus/2019-ncov/community/colleges-universities/considerations.html 

CDC Statement on COVID-19 Vaccines for Moderately or Severely Immunocompromised People, updated 1/7/2022  https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html 

CDC Statement on ACIP Booster Recommendations. Released 9/24/21. https://www.cdc.gov/media/releases/2021/p0924-booster-recommendations-.html 

CDC's Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines Currently Authorized in the United States. Updated 8/13/2021. https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html  

CDC's Understanding and Explaining Viral Vector COVID-19 Vaccines. https://www.cdc.gov/vaccines/covid-19/hcp/viral-vector-vaccine-basics.html

Texas Health and Human Services, Department of State health Services. COVID-19 Vaccine Information, updated 1/7/2022. https://www.dshs.texas.gov/coronavirus/immunize/vaccine.aspx  

https://www.fda.gov/media/150723/download, July 12, 2021 

https://www.fda.gov/news-events/press-announcements/fda-approves-first-covid-19-vaccine , August 23, 2021 

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