Questions About the COVID-19 Vaccine?

Last updated: August 19th

Q: Which COVID-19 vaccines have been authorized for use in the US? 

A: The US has two mRNA and one viral vector COVID-19 vaccines with good safety and efficacy profiles recommended for use in response to the pandemic.

  • On May 12, 2021, CDC approved the use of the Pfizer-BioNTech COVID-19 vaccine in persons aged 12-15 years for the prevention of COVID-19. This recommendation came after this vaccine’s Emergency Use Authorization (EUA) was granted on May 11th by the Food and Drug Administration. The Pfizer-BioNTech COVID-19 vaccine was approved by the CDC in persons aged > 16 years on December 12, 2020 and received an EUA from the FDA on December 11, 2020.
  • On December 18, 2020, Moderna's mRNA vaccine was approved under an EUA and on December 19, 2020, CDC recommended its use in persons aged ≥18 years for the prevention of COVID-19.
  • On February 27, 2021, the FDA approved Janssen’s viral vector COVID-19 vaccine under an EUA for use in persons ≥ 18 years of age, and on February 28, 2021, the CDC recommended the use of this vaccine. There was a pause on Janssen vaccine administration on April 13, 2021 due to a safety signal detected for cerebral venous sinus thrombosis- (CVST) with thrombocytopenia.  On April 23, 2021 the Advisory Committee on Immunization Practices concluded that the benefits of resuming Janssen COVID-19 vaccination among persons aged ≥ 18 years outweighed the risks and reaffirmed its interim recommendation under FDA's EUA, which includes a new warning for rare clotting events among women aged 18-49 years.

Q: Which COVID-19 vaccine does the AAP recommend?

A: COVID-19 vaccines are life-saving vaccines. Individuals should receive the first vaccine they are eligible to receive and that is available in their community. Delaying immunization leaves an individual vulnerable to infection for a longer period of time, placing them at greater risk of serious illness and death. AAP recommends COVID-19 vaccination for all adolescents 12 years of age and older who do not have contraindications using a COVID-19 vaccine authorized through EUA, recommended by CDC, and appropriate for their age and health status. AAP also supports coadministration of COVID-19 vaccines with other vaccines on the immunization schedule. See AAP policy.

Research trials have shown COVID-19 vaccines are highly effective against severe COVID-19 illness, hospitalization, and death. Those who are 12-17 years old should receive the Pfizer-BioNTech vaccine; while those 18 years of age or older may receive what is recommended and available in their community. Each was developed and evaluated at different points in time against different strains of COVID-19 within distinct geographic regions and populations, and all three vaccines were found to have comparable vaccine efficacy. Women younger than 50 years old should be aware of the rare risk of blood clots with low platelets after vaccination with the Janssen COVID-19 vaccine, and that other COVID-19 mRNA vaccines are available where this risk has not been seen.

Q: What is the difference between COVID-19 mRNA and viral vector vaccines?

A: Messenger RNA (mRNA) Vaccines
These vaccines use a newer technology where mRNA is wrapped in a coating (lipid nanoparticle) so it can enter our cells. The mRNA in the vaccine teaches our cells how to make copies of a spike protein. Once the spike protein is made, two things occur: (1) the cell breaks down the mRNA (instructions) and gets rid of them, and (2) the spike protein triggers an immune response inside of our bodies, which produces antibodies. These antibodies protect us from getting infected if the real virus enters our bodies.

Viral Vector Vaccines
Viral vector vaccines use a modified, harmless version of a different virus to deliver instructions to our cells. The virus enters the cell and teaches it how to make copies of a spike protein, which then triggers an immune response inside of our bodies. This immune response results in the production of antibodies which protect us from getting infected if the real virus enters our bodies.

Q: What is the current status of COVID-19 vaccine research in children and adolescents? 

A: To date, Pfizer-BioNTech is in the process of testing its COVID-19 vaccine in children younger than 12 years and anticipates filing an EUA for ages 2-11 years in September 2021. Pfizer-BioNTech's EUA for vaccination indications in adolescents 12-15 years old was approved on May 11, 2021, their EUA for 16 years and older was approved in December 2020 and they submitted an application for the Biologic Licensing Agreement (BLA) for 16 years and older with the FDA in May. Moderna has started a clinical trial to test its COVID-19 vaccine in children under 12, including babies as young as six months and is expecting to enroll 6,750 healthy children in the US and Canada. The company has filed an EUA with the FDA for use of its COVID-19 vaccine in adolescents 12 to 17 years old and filed a BLA for use in 18 years and older in June. Novavax recently completed enrollment of its pediatric clinical trial looking at their recombinant protein vaccine candidate against COVID-19 in adolescents 12 to 17 years old. This study will include 3,000 adolescents aged 12-17 across up to 75 sites in the United States. Janssen and Astra Zeneca also have plans to study their vaccines in younger age groups.

The AAP actively advocated for the inclusion of children and pregnant women in COVID-19 vaccine trials, and sent multiple letters and comments to FDA, the Vaccines and Related Biological Products Advisory Committee (VRBPAC), the White House COVID-19 Response Team; and has also issued multiple press statements.

Q: Is it safe for pregnant or lactating women to receive COVID-19 vaccine? 

A: Participants who report pregnancy following COVID-19 vaccination are enrolled in the V-SAFE pregnancy registry. Participants are contacted once per trimester, after delivery, and when the infant is 3 months old.

Early safety data showed that no major safety concerns have been reported in pregnant persons. Over 30,000 pregnancies have been reported to V-SAFE (safety monitoring system). Safety profiles comparing persons 16-54 years reported similar findings among both pregnant and non-pregnant persons who received Pfizer-BioNTech and Moderna mRNA vaccines.

Guidance from the American College of Obstetricians and Gynecologists (ACOG) recommends that

  • Pregnant individuals should have access to COVID-19 vaccines
  • COVID-19 vaccines should be offered to lactating individuals similar to non-lactating individuals
  • Women under age 50, including pregnant individuals can receive any FDA authorized COVID-19 vaccine available to them; however, they should be aware of the rare risk of thrombosis with thrombocytopenia syndrome after receipt of the Janssen COVID-19 vaccine and that other FDA authorized COVID-19 vaccines are available.

Q: Are there any safety concerns with the new technologies (mRNA and nanotechnology) being used in the development of the Pfizer-BioNTech and Moderna COVID-19 vaccines?

A: There are no known additional risks of mRNA vaccines or lipid nanoparticles. Live attenuated viral vaccines, such as measles vaccine, induce an immune response that is similar to natural infection. mRNA vaccines, on the other hand, simply give the body instructions to produce one very specific part of a virus – in this case the so-called spike protein – to then induce an immune response. Because mRNA is broken down very quickly in the human body, to do its work it needs to be able to get into our cells, and so it is wrapped in a lipid nanoparticle. Once it gets into the cells to deliver the instructions, the mRNA breaks down very quickly. It does not get into the nucleus of the cell, or into our genes. Since the new mRNA vaccines have been administered, their safety profiles are reassuring.

Since April 2021, several cases of myocarditis and pericarditis have been reported in adolescents and young adults following receipt of mRNA vaccines – most often following the 2nd dose. Pediatricians should consider myocarditis and pericarditis in adolescents or young adults with acute chest pain, shortness of breath, or palpitations and report any suspected cases post COVID-19 vaccination to VAERS. CDC continues to monitor the situation and has created guidance for health care providers.

Clinical Considerations: Myocarditis after mRNA COVID-19 Vaccines | CDC 

Q: What side effects are noted to date with COVID-19 mRNA vaccines (Pfizer-BioNTech and Moderna)?

A: The side effects have been similar to other routine vaccines- sore arm, redness, fatigue, fever, chills, headache, myalgia, and arthralgia. The side effects are temporary and mostly mild or moderate. Side effects may be worse after the second dose in some individuals. Anaphylaxis has been observed following receipt of COVID-19 mRNA vaccines, but this has been rare. A full listing of the side effects is now available on the FDA website and a summary is found in the fact sheet that is provided to everyone who receives the vaccine. The potential for side effects that cause individuals to miss work should also be considered in planning.

(Information from the AAP. Full webpage can be found here.)

Questions About COVID-19?


Quarantine if you have been in close contact (within 6 feet of someone for a cumulative total of 15 minutes or more over a 24-hour period) with someone who has COVID-19, unless you have been fully vaccinated. People who are fully vaccinated do NOT need to quarantine after contact with someone who had COVID-19 unless they have symptoms. However, fully vaccinated people should get tested 3-5 days after their exposure, even if they don’t have symptoms and wear a mask indoors in public for 14 days following exposure or until their test result is negative.

What to do

  • Stay home for 14 days after your last contact with a person who has COVID-19.
  • Watch for fever (100.4◦F), cough, shortness of breath, or other symptoms of COVID-19.
  • If possible, stay away from people you live with, especially people who are at higher risk for getting very sick from COVID-19.

After quarantine

  • Watch for symptoms until 14 days after exposure.
  • If you have symptoms, immediately self-isolate and contact your local public health authority or healthcare provider.

You may be able to shorten your quarantine

Your local public health authorities make the final decisions about how long quarantine should last, based on local conditions and needs. Follow the recommendations of your local public health department if you need to quarantine. Options they will consider include stopping quarantine

  • After day 10 without testing
  • After day 7 after receiving a negative test result (test must occur on day 5 or later)



Isolation is used to separate people infected with COVID-19 from those who are not infected.

People who are in isolation should stay home until it’s safe for them to be around others. At home, anyone sick or infected should separate from others, stay in a specific “sick room” or area, and use a separate bathroom (if available).

What to do

  • Monitor your symptoms. If you have an emergency warning sign (including trouble breathing), seek emergency medical care immediately.
  • Stay in a separate room from other household members, if possible.
  • Use a separate bathroom, if possible.
  • Avoid contact with other members of the household and pets.
  • Don’t share personal household items, like cups, towels, and utensils.
  • Wear a mask when around other people if able.

Learn more about what to do if you are sick and how to notify your contacts.

When You Can be Around Others After You Had or Likely Had COVID-19

Most people do not require testing to decide when they can be around others; however, if your healthcare provider recommends testing, they will let you know when you can resume being around others based on your test results.

For Anyone Who Has Been Around a Person with COVID-19

Anyone who has had close contact with someone with COVID-19 should stay home for 14 days after their last exposure to that person.

However, anyone who has had close contact with someone with COVID-19 and who meets the following criteria does NOT need to stay home.

  • Someone who has been fully vaccinated and shows no symptoms of COVID-19. However, fully vaccinated people should get tested 3-5 days after their exposure, even they don’t have symptoms and wear a mask indoors in public for 14 days following exposure or until their test result is negative.


  • Someone who has COVID-19 illness within the previous 3 months and
  • Has recovered and
  • Remains without COVID-19 symptoms (for example, cough, shortness of breath)

I think or know I had COVID-19, and I had symptoms

You can be around others after:

  • 10 days since symptoms first appeared and
  • 24 hours with no fever without the use of fever-reducing medications and
  • Other symptoms of COVID-19 are improving*

*Loss of taste and smell may persist for weeks or months after recovery and need not delay the end of isolation​

Note that these recommendations do not apply to people with severe COVID-19 or with weakened immune systems (immunocompromised).

I tested positive for COVID-19 but had no symptoms

If you continue to have no symptoms, you can be with others after 10 days have passed since you had a positive viral test for COVID-19.

If you develop symptoms after testing positive, follow the guidance above for “I think or know I had COVID-19, and I had symptoms.”

I was severely ill with COVID-19 or have a weakened immune system (immunocompromised) caused by a health condition or medication.

People who are severely ill with COVID-19 might need to stay home longer than 10 days and up to 20 days after symptoms first appeared. People with weakened immune systems may require testing to determine when they can be around others. Talk to your healthcare provider for more information. Your healthcare provider will let you know if you can resume being around other people based on the results of your testing.

People who are immunocompromised should be counseled about the potential for reduced immune responses to COVID-19 vaccines and the need to continue to follow current prevention measures (including wearing a mask, staying 6 feet apart from others they don’t live with, and avoiding crowds and poorly ventilated indoor spaces) to protect themselves against COVID-19 until advised otherwise by their healthcare provider. Close contacts of immunocompromised people should also be encouraged to be vaccinated against COVID-19 to help protect these people.

(Information from the CDC. Full webpage can be found here.)

We are here for you to answer any questions you may have as we stay up-to-date with the CDC in regards to COVID-19


Back to Coronavirus Page