Coronavirus Information and Resources

COVID-19 Vaccine Frequently Asked Questions

Last revised 12/21/20


A vaccine is a chemical preparation that stimulates your body’s immune system to recognize and control of a virus, bacterium, or other microbe. After vaccination, your body will be better able to protect you against that microbe in the future. 

The current COVID-19 vaccines are made in the lab using components of messenger RNA (mRNA). All living things make mRNA in order to make the proteins in the body. The vaccines use mRNA that can tell and give a message to our cells to make a virus protein, called Spike protein, that is essential for the novel coronavirus to invade our cells and make us sick. In order to help our cells do this, the mRNA is coated with tiny oil droplets that protect the mRNA until it does its job. Once this Spike protein is made and our immune system “sees” the protein, this triggers an immune response to the protein that prepares us to respond (respond by making “antibodies” ) if our body sees the novel coronavirus at some point in the future. 

Antibodies are also proteins. They function as soldiers that protect the body against harmful particles like CoVID19

The studies of the two mRNA vaccines available now tested in tens of thousands of people. Half received the vaccine, and half received an injection without the vaccine. People were then followed to see who got COVID-19. After two doses, the vaccine reduced the expected number of COVID-19 in the vaccine group by 94-95%! In addition, those in the vaccine group that got COVID-19 had milder cases than those that were not vaccinated.

The FDA has authorized the use of the Pfizer vaccine for individuals 16 years and older. The vaccine is intended for the general public with very few exceptions. People whose jobs exposed them to others on a regular basis should get the vaccine early. People who are older and/or have underlying illnesses, such as diabetes, high blood pressure, and obesity, are especially encouraged to get vaccinated. Certain ethnic groups, particularly African-Americans, Latinx, Native Americans, have high rates of severe COVID-19 and death.

At the moment, children under age of 16 have not been studied and are therefore not part of this vaccination program. Studies are ongoing to evaluate safety and efficacy in children.

Those with a history of severe allergic reaction (e.g. anaphylaxis) to any component of the Pfizer-BioNTech vaccine should not get this vaccine. 

Persons with a history of severe allergic reaction to another type of vaccine or injectable medication have been cautioned to weigh risks and benefits, and if vaccinated, would require a longer observation period (30 minutes instead of 15 minutes) following their injection. 

There is not much data for people that are on immunosuppressive medications/have HIV etc. These people are at higher risk of getting severe COVID19 virus infection. Since these vaccines do not have the live virus, if there is no other contraindication, these vaccines can be administered.
We recommend that you discuss with your provider to make an informed decision.

Yes. No vaccine is 100% effective. However, even if you get COVID-19, studies have shown that you will have a milder case of it. According to the studies, these vaccines are 94-95% effective.

Probably yes. The vaccine itself does not have the live virus and it will not produce the virus in your body. But if you are an asymptomatic carrier (a person with the virus with no symptoms), it is unknown if vaccinated people can shed the virus. If they do, they could give the virus to others. This is why it is very important that we continue to follow current prevention guidance – mask-wearing, handwashing, and social distancing—even after we have been vaccinated. 

mRNA technologies have been studied for more than a decade. The mRNA vaccines have gone through the same rigorous process that other vaccines. medicines, or devices must go through. No phases of this process have been skipped. The quick authorization for these vaccines has much more to do with the Federal government funding the mass production of these vaccines much earlier than usual. 

The vaccines have been quite safe as tested so far. To this moment, some people getting vaccinated have had fever, fatigue, and pain at injection site for a day or two after the injection. A few individuals with history of severe allergies have had allergic reactions to the Pfizer vaccine. No such reactions have been seen with the other vaccine so far.  

The most common side effect is soreness in the arm you got the vaccine, as most people have a sore arm after getting the vaccine. Sometimes the arm can also get a little red and swollen where the vaccine was given. 

After that, feeling tired, having body aches, and headaches are the most common side effects of the vaccine. These side effects are more likely to happen after the second dose of the vaccine, although they can happen after the first dose. These most common side effects can happen with many vaccines, and are a sign they are working in our bodies to activate our immune system, which is why they happen more with the second dose of the vaccine.

Less commonly, some people who received the vaccine had stomach ache, nausea, vomiting, and diarrhea, and a few people had chills and sometimes a fever. 

We do not expect that there will be long-term side effects from the vaccines, but at the moment we do not have long-term safety data. 

No. The technology used to produce these mRNA vaccines does not involve live virus. 

We currently do not have data on the safety of COVID-19 vaccines in pregnant women, although additional studies are ongoing. mRNA vaccines are not expected to be harmful and the benefits may outweigh the risks, especially because an infection with COVID-19 in pregnant women has been associated with worse outcomes for the woman (e.g., ICU admission, mechanical ventilation, and death) and the possibility of worse outcomes for the pregnancy (e.g., preterm birth). 

We currently do not have safety data on vaccine administration in breastfeeding women. However, mRNA vaccines are not considered live virus vaccines and are not thought to pose a risk to the breastfeeding women or her infant. 

The current vaccine is not approved for children under 16 years of age. Studies to evaluate safety and efficacy are ongoing in children. 

The Pfizer-BioNTech and Moderna vaccines both include a two-injection series. It is important to complete the two doses in order to maximize your chances of protection. For the Pfizer vaccine, the second dose should be administered 3 weeks (21 days with a grace period of 4 days, 17-21 days) after the first. If more than three weeks pass since the first vaccine is received, the second dose should be given at the earliest opportunity. There is no need to repeat any doses. The Moderna vaccine’s second dose should be administered 28 days after the first.

Yes. If you are currently not infected and your quarantine period is over, you can get the vaccine. According to studies, having COVID-19 19 infection does not give you lifelong protection against CoVID19.

No. If you actively have CoVID19 or are currently sick, it is recommended to delay taking the vaccine until your symptoms resolve and the recommended quarantine/isolation period is completed. Studies have shown that someone who gets infected, does not get reinfected for 3 months/90 days. If desired, vaccine can be deferred for 3 months.

These vaccines are causing the body to make antibodies against the spike protein. These vaccines should not affect the antibodies that were created in your body. If you get tested to check if your body has antibodies against spike proteins or not after vaccination, it may indicate that you either had prior infection or were vaccinated.

Since the vaccines do not have the virus, they should not interfere with the PCR testing.

Absolutely yes. Because of limited data we do not know yet for how long these vaccines will be protective and will produce protective antibodies. Until we have more data and more people get vaccinated, we all should continue practicing the public health recommendations:

  • wearing a mask, social distancing-staying 6 feet away, hand washing and avoid crowds.

According to CDC and the studies it may take up to 1 to 2 weeks after receiving the second dose for your body to produce an effective immune response.

If you had a high-risk exposure to someone with COVID-19 (close together without masks for >15 minutes) in the 14 days prior to getting your vaccine, and you develop symptoms, you should consider getting tested for COVID-19. 

If you have symptoms that both the vaccine and COVID-19 cause (muscle aches, fatigue), and you received the vaccine in the last 2-3 days, it can be hard to tell if these are coming from a potential COVID-19 infection or the vaccine. If you feel overall well, don’t have any other concerning symptoms, and don’t have a fever, you likely do not need to be tested for COVID-19.

However, if you start to feel worse or develop other symptoms (i.e. cough, difficulty breathing, runny nose, sore throat, loss of taste or smell) you should likely be tested as these are not common side effects of the vaccine. If you have a fever, you should also consider getting a COVID-19 test.

We do not know how long the vaccine will protect you. We do know that people who get the vaccine have much higher antibody levels than those who got COVID-19 infection. These antibody levels stay high for at least 90 days.


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