FAQs Regarding SARS-CoV-2 Vaccine

Updated: January 13, 2021

Below is a list of frequently asked questions about the SARS-CoV-2 vaccine that came up during recent Columbia town hall discussions. These FAQs will be updated as new vaccines and information become available.

Please be aware that you should discuss the vaccine and any questions you have about it with your healthcare provider. The vaccines are currently being distributed to various states. In New York City, at present, prioritization of the vaccine will follow New York State and CDC guidance. 

Everyone—including those who were vaccinated—must continue to practice protective behavior, including wearing a face covering, physical distancing, washing hands, staying home if sick, and avoiding nonessential travel. This is important since it is not yet known if the vaccines protect against asymptomatic infection and prevent transmission to others.

There are currently two vaccines that have received Emergency Use Authorization (EUA) by the U.S. Federal Drug Administration (FDA). These include the Pfizer BioNTech vaccine, which received EUA on December 11, 2020, and the Moderna vaccine, which received EUA on December 18, 2020.

Both the Pfizer and Moderna vaccines use genetic material known as messenger RNA (often abbreviated as mRNA) that cells use to make proteins. When the vaccines are injected into the body, the mRNA enters human cells and instructs the cells to make a protein that mimics the spike proteins found on the surface of the coronavirus. These vaccine-induced proteins then stimulate the immune system to produce antibodies to fight the virus. Once produced, the antibodies latch onto the virus spike protein and prevent it from entering your cells and making you sick.

It is important to note that the mRNA is not able to alter or modify a person’s genetic makeup (DNA). The mRNA from a COVID-19 vaccine never enter the nucleus of the cell, which is where our DNA is situated. That is also the reason why these vaccines should not affect fertility (they do not cause sterility) and should not affect the fetus in pregnant women. However, more studies are needed to evaluate vaccine safety among pregnant and breastfeeding women.  

Updated: January 13, 2021

The vaccines are currently being distributed to various states. In New York City, at present prioritization of the vaccine will follow New York State and CDC guidance which is outlined below:

Phase 1

Phase 1a:

  • Health care personnel
  • Patients and staff in long-term care facilities

Phase 1b:

  • Persons 65 years and older
  • Frontline essential workers (e.g. first responders, grocery story workers, transit workers, fire, police, national guard)

Phase 1c:

  • Persons 65-74 years
  • Persons 16-64 with high-risk medical conditions
  • Other essential workers

Phase 2

  • Persons 16-64 years old without high-risk medical conditions

Preliminary findings from the Pfizer and Moderna vaccine trials showed that these vaccines were more than 90% effective in preventing symptomatic COVID-19. Often referred to as “efficacy,” vaccine efficacy refers to the percent reduction in number of COVID-19 cases (e.g., 95%) in those who received the vaccine compared with those who received placebo (no vaccine).

No serious side effects have been reported with either the Pfizer or the Moderna vaccines to date.  The safety of both vaccines was determined by independent Data Safety and Monitoring Boards (DSMBs). Safety data will continue to be monitored after the vaccines begin to be used in order to determine longer term safety profiles.

It is important to note that the Pfizer and Moderna trials did not include individuals younger than 18 years old, pregnant or nursing women, or immunocompromised individuals and therefore, whether these vaccines work or are safe in  these groups cannot been determined at this time.

Mild to moderate side effects have been reported for both the Moderna and Pfizer vaccines among study participants. These side effects include pain or swelling at the injection site, fatigue, chills, muscle aches, and headaches. Most of these side effects resolved promptly. Additionally, in both the Moderna and Pfizer trials, a small number of study participants reported enlarged lymph nodes (swelling in the arm pit and tenderness of the side where the vaccine was injected).  

Yes, the University is committed to ensuring that all eligible individuals have access to COVID-19 vaccines, consistent with local prioritization. A University vaccination program will be applied uniformly across University units and will encompass prioritizing groups eligible for vaccination in the various phases described in question 3 based on local and national guidance.

At this point in time, the University is strongly recommending, but not mandating vaccination for eligible persons.

If you are eligible as part of the priority groups listed question 3 above, you will be notified by the University once the vaccine becomes available on where and when you can get vaccinated. For groups not included in Phases 1 and 2, information regarding administration sites will be disseminated as New York City progresses through the vaccination phases and more vaccine supplies become available.

Prioritization will be consistent with New York City, New York State and CDC guidance.


Vaccination provided at Columbia University, New York Presbyterian Hospital or through ColumbiaDoctors practices will be at no cost to faculty, staff and students.

Medical expenses will be covered by insurance.  If you work for Columbia and are covered under a Columbia insurance program, those expenses will be paid under your. Insurance plan.

For the foreseeable future, everyone including those who were vaccinated must continue to practice protective behaviors including wearing a face covering/mask, physical distancing, and other measures, such as avoiding nonessential travel. This is important since it is not yet known if the vaccines protect against asymptomatic infection and consequently prevent transmission to others. In addition, it will take time to achieve high vaccine uptake (estimated at 70-80%) in order to achieve herd immunity, i.e. sufficient population level protection from transmission of the virus.  

Yes, the University will monitor individuals who get vaccinated to ensure that they receive the recommended vaccine regimen (e.g. two doses for the Pfizer and Moderna vaccines), to monitor for severe side effects and to determine uptake by various priority groups.

Getting vaccinated is at present not linked to individual or institutional decisions regarding return to campus.

Proof of vaccination will be maintained in the New York Presbyterian Hospital or Columbia Health electronic medical record databases, depending on where you get vaccinated. You will be able to access your medical records through the existing user portals including MyChart or your Columbia Health account.

Yes, both the Pfizer and Moderna vaccines are similar in effectiveness for prevention of symptomatic COVID-19 and have similar safety profiles. Vaccination, whether with the Moderna or Pfizer vaccine, will be based on availability of supply.  It is important to note, that individuals who received one vaccine will be guaranteed the second dose of that vaccine, as recommended.

You will be provided with information regarding the vaccine and most common side effects that have been reported.

Yes, all individuals, including those vaccinated, will need to continue to participate in the University testing program (e.g. gateway, sampling, mandatory testing). The reason for this is that the vaccines have not been shown to prevent asymptomatic infection, only clinical illness. It is assumed for now that individuals who have been vaccinated can still acquire the SARS-CoV-2 virus and may transmit to others. Also, the vaccines do not interfere with the results of the SARS-CoV-2 diagnostic testing.

No, the vaccines do not contain the virus or any part of the virus. Rather, the vaccine contains mRNA that codes for a single viral protein that is unable to replicate in the way a live virus can or cause COVID-19.

This has yet to be determined and is currently under study. The main focus of the Pfizer and Moderna studies was on determining whether the vaccines protected from getting symptomatic COVID-19 (i.e. getting sick with COVID-19).

It has been shown that people can get infected by the coronavirus but not show any symptoms, which is known as asymptomatic infection. These individuals can still transmit the virus to others. Research is under way to determine whether the vaccines will prevent asymptomatic infection and therefore reduce the risk of transmission from someone who has asymptomatic infection to others. Until this is determined, it is critically important for everyone to get vaccinated to protect themselves and to continue practicing protective behaviors, including wearing a face covering/mask and physical distancing, to protect themselves and others from catching and transmitting the virus.

Yes, both the Pfizer and Moderna trials included groups who are at high risk for COVID-19, including those who are 65 years and older, have underlying medical conditions (such as diabetes, high blood pressure, obesity), among others. About 30% of the participants in both the Pfizer and the Moderna vaccine studies were African American/ Black or Latinx. Across all groups, both studies found the vaccines to be safe and effective.

The duration of protection from COVID-19 provided by these two vaccines is not known as of yet. Researchers will continue to monitor study participants to determine the duration of protection.  

Both the Pfizer and Moderna vaccines require two doses to be effective. The second dose of the Pfizer vaccine is administered three weeks after the first dose while the second dose of the Moderna vaccine is administered four weeks after the first.

The Pfizer and Moderna vaccine studies found that two doses were needed to optimize the immune response and provide the best protection from COVID-19. Therefore, the 2-dose regimen is strongly recommended and will be necessary for documentation of full vaccination.

No. This was not evaluated and there is no evidence that the vaccines are interchangeable. If you get a first dose of one vaccine, you should get a second dose of the same vaccine. Individuals administering the vaccine will be tracking this issue.

It typically takes a few weeks after the final dose of a vaccine for the body to build up immunity to the disease. However, it is not necessary for one to quarantine between each dose. Individuals are recommended to continue with their daily lives while following COVID-19 public health recommendations.

According to CDC guidance, second doses administered within a grace period of ≤ 4 days from the recommended date for the second dose are considered valid; however, doses administered earlier do not need to be repeated. The second dose should be administered as close to the recommended interval as possible. However, there is no maximum interval between the first and second dose for either vaccine.

Currently, the safety of any vaccine combination has not been determined and therefore the CDC advises against the mixing of COVID-19 vaccines. Research regarding the potential need for a booster injection of a COVID-19 or routine vaccination is underway.

Getting the influenza vaccine is still very important as one can be infected with both influenza and the coronavirus. Influenza vaccination will also prevent a surge of influenza cases in hospitals that may be overwhelmed with COVID-19 patients. Getting both the influenza and COVID-19 vaccine around the same time is considered safe, though experts recommend spacing of the vaccinations by a few days to weeks apart.  

Yes, health officials believe that the Pfizer and Moderna vaccines will offer protection against the different variants of the coronavirus. Research is ongoing to further study this issue.

Yes, as per CDC recommendations, vaccination should be offered to persons regardless of history of prior symptomatic or asymptomatic coronavirus infection, including a positive antibody test. For persons who experience lingering symptoms for weeks and months after diagnosis (i.e., “COVID-19 long-haulers”), vaccination is similarly considered safe and likely efficacious.

For persons with current COVID-19, vaccination should be deferred until recovery from acute illness and can be deferred up until 90 days after the current episode.

Per CDC and FDA recommendations, those who have had a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccines should not be vaccinated. For those who have had a severe allergic reaction to another vaccine or injectable treatment (intramuscular, intravenous, or subcutaneous) the vaccine can still be administered; however, it is recommended that the risks be discussed with a healthcare provider and that the recipient be monitored for 30 minutes post-vaccination. For those with any other allergy (e.g. food, pollen, pets), vaccination should be offered. All individuals who received vaccines should be observed for about 15 minutes after vaccination.

The Pfizer and Moderna vaccines are very similar in composition. They consist of the mRNA particle, water, lipids, salt, sugar, and FDA-approved buffers. A complete list of the ingredients can be found here for Pfizer (page 11) and here for Moderna (page 11).

No, Guillain-Barre is not a contraindication for the Pfizer or Moderna vaccine. Individuals with such a history should discuss this with their provider.

Currently, there are no data on the safety or efficacy of COVID-19 vaccination in persons who received monoclonal antibodies or convalescent plasma as part of COVID-19 treatment. Therefore, it is recommended that vaccination be deferred for at least 90 days after receiving such treatment to avoid interference of the treatment with vaccine-induced immune responses.

Persons who have been identified recently as a close contact of someone with COVID-19 should defer vaccination until quarantine period has ended to avoid exposing healthcare personnel (HCP) or other persons during vaccination visit.

Currently, there are no data on the safety of COVID-19 vaccines in pregnant or breastfeeding women, though studies to collect these data are ongoing. Per CDC recommendations, pregnant or breastfeeding persons who are part of a group (e.g., healthcare worker) that is recommended to receive a COVID-19 vaccine, may choose to be vaccinated due to their increased COVID-19 risk. A discussion with a healthcare provider can help inform this decision.

Additionally, there is no recommendation for routine pregnancy testing before receipt of a COVID-19 vaccine. Those who are trying to become pregnant do not need to avoid pregnancy after mRNA COVID-19 vaccination. A consultation with a healthcare provider is recommended in making this decision.

According to CDC recommendations, the vaccine may be administered to persons with underlying medical conditions who have no contraindications to vaccination. This guidance is based on the studies that have demonstrated similar safety and efficacy profiles in persons with underlying medical conditions compared to those without such conditions.

For those who are immunocompromised, safety and efficacy of vaccine has yet to be determined given the limited data for these groups. However, immunocompromised persons may still receive COVID-19 vaccines, with counseling, unless otherwise contraindicated given increased risk for COVID-19.

At this point in time, children are not considered a priority group for early phases of vaccination given their low risk for severe disease.

For the Pfizer vaccine, preliminary data suggest that the vaccine was safe and effective in individuals 16-17 years old. For the Moderna vaccine, individuals younger than 18 years old were not included in the study and therefore, no data currently exist. However, studies are ongoing to determine the safety and efficacy for the Pfizer and Moderna vaccines in both children and adolescents.

Under federal law, manufacturers and distributors of COVID 19 vaccines are entitled to immunity as long as there is no willful misconduct.


Under federal law, manufacturers and distributors of COVID 19 vaccines are entitled to immunity from suit as long as there is no willful misconduct. Under federal law, you cannot sue FDA for approving the vaccine.