COVID-19 Vaccine Information: Distribution and Answers to Other Common Questions

The Pfizer and Moderna vaccines consist of genetic material called mRNA encased in tiny particles that transport it into our cells. From there, it stimulates the immune system to make antibodies that protect against the virus. These vaccines do not have any impact on our genes. The vaccine material breaks down in the body shortly after it is taken into our cells. The Janssen vaccine is carried into the cells by an inactive adenovirus (which is a common virus).

Learn more about the differences between the vaccines

Within two weeks. Because the vaccine is very effective, antibody testing after receiving the vaccine is not recommended.

You should wait until you are completely better and then get your vaccine.

Yes, you should still get vaccinated as the antibodies to COVID-19 that your body made during your infection will last only a few months, and then you are at risk for a repeated infection. If you test positive for COVID-19 prior to your FIRST vaccine, you should wait 4 weeks before getting your first vaccine dose (or 90 days if you received treatment with Monoclonal Antibody Infusion). If you test positive for COVID-19 after the first vaccine but prior to the SECOND vaccine, you should wait 10 days from the positive test (or 90 days if you received treatment with Monoclonal Antibody Infusion) and be fully recovered and non-infectious before receiving the second dose.

You should wait for 10 days from when you first tested positive and be fully recovered before getting your second dose. You should still get the second dose.

The extent to which antibodies that develop in response to SARS-CoV-2 infection are protective is still under study. If these antibodies are protective, it's not known what antibody levels are needed to protect against reinfection. Therefore, even those who previously had COVID-19 can and should receive the COVID-19 vaccine. Although data is limited at this time, individuals should wait four weeks to receive the vaccine after first testing positive for SARS CoV-2. This recommendation may change as more data becomes available.

The Pfizer COVID-19 vaccine is a two-dose series. The second dose of the Pfizer vaccine should be given 21 days from the first dose. If scheduling conflicts prevent the second dose from being administered at 21 days as recommended, then it should be given between 19 and 24 days from the first dose.

The Moderna vaccine is a two-dose series. The second dose of the Moderna vaccine should be given 28 days from the first dose. If scheduling conflicts prevent the second dose from being administered at 28 days as recommended, then it should be given between 26 and 31 days from the first dose.

The Janssen vaccine is a single dose.

Re-starting the vaccine series is NOT recommended at this time if there is a delay in administering the second dose of either vaccine type.

To protect others, you must wait until after your quarantine period ends to get vaccinated.

When you get the vaccine you will know if you are getting a one dose or two dose vaccine, but not the specific manufacturer. The vaccines are equally effective in preventing COVID-19. We are administering whichever vaccine is allocated to us by the Department of Health at the time of your first appointment. If applicable, your second dose will be from the same manufacturer as your first dose.

We encourage you to take any one of the three vaccines now available, unless you have a medical contraindication (such as a severe allergy to the vaccine or to one of its ingredients). All three COVID-19 vaccines have been shown to reduce the risk of becoming infected with COVID-19 and being hospitalized. Most importantly, all have been shown to eliminate the risk of developing severe disease and death due to COVID-19.

Yes, you will have the opportunity to schedule your second dose as soon as you receive your first dose. We do not expect any shortages for the second vaccine dose.

COVID-19 and other vaccines may now be administered without regard to timing of other vaccines. This includes simultaneous administration of COVID-19 and other vaccines on the same day.

We are prioritizing appointments for individuals with medical conditions considered high risk with COVID infection.

View a list of pediatric and adult high-risk medical conditions

Those aged 12+ are eligible to receive the Pfizer vaccine at this time.

Learn more about the vaccine and those 12 and older

You do not need a Yale New Haven Health MyChart account to get a vaccine. However, having a MyChart account will help you keep track of when you are scheduled to get a second dose.

View our frequently asked questions page to learn more about the vaccine.

View our vaccine location pages for vaccination site details.

Please bring a photo ID, mask, and your insurance card if available.

Yes. Patients are allowed to bring one support person for their vaccine appointment if they need assistance. 

After you schedule your vaccine, you will receive a reminder to the email address you used to sign up/sign into MyChart to schedule your appointment. You can also find the confirmation by logging into MyChart and selecting “Visits” > “Appointments and Visits”.

To cancel or reschedule appointments via your computer, log into MyChart, click “Visits”, and then "Appointments and Visits". Then, locate the appointment you would like to cancel or reschedule. If rescheduling, you will be prompted to select a new date and time and confirm.

View a video on how to reschedule or cancel your appointment on the MyChart website

To cancel or reschedule appointments via your MyChart mobile app, open the app and click "Appointments". Then, locate the appointment you would like to cancel or reschedule. If rescheduling, you will be prompted to select a new date and time and confirm.

View a video on how to reschedule or cancel your appointment in the MyChart mobile app

During your appointment to receive the first dose, you will receive assistance scheduling the second dose. If you are unable to be assisted with this on site, please log into your MyChart account, select Appointments, and schedule your second dose via the ticketing feature. If you do not have a MyChart account or do not see an appointment for your second dose in your account, please call 1-833-ASK-YNHH (275-9644).

All vaccines are approved by the Federal Drug Administration (FDA) for Emergency Use Authorization (EUA). In clinical trials, there have been a very limited number of allergic or other severe adverse reactions with these vaccines.

Through a reporting system called VAERS, the CDC is actively tracking and investigating severe allergic reactions (e.g. anaphylaxis) and other possible severe reactions to the vaccines. To date, these severe reactions have been very low as a percentage of total vaccinations given, and the CDC continues to all three vaccines as being safe and critical to combating this pandemic. Learn more about VAERS here.

Side effects such as fever, headaches, body aches, fatigue and nausea are common but typically last 1-2 days only. It is not possible to “catch COVID” from the vaccine.

As an added measure of safety, we ask individuals vaccinated at our clinics to stay on-site for observation for at least 15 minutes after getting the vaccine to make sure they can be treated promptly and correctly if they experience a sudden reaction. Anyone who has had an allergic reaction to any vaccine, injectable drug or food in the past is asked to stay for a 30 minute observation period

Based upon data, our scientific experts agree that the current vaccines will be effective against variants, so you should get vaccinated as soon as possible. There have actually been over 40 variants described to date and more will occur as time goes on. The most important thing we as a society can do to avoid the impact of new variants is to get vaccinated, and continue our efforts to use masks, wash our hands, avoid crowds and maintain social distancing. Our medical leaders will continue to review the scientific data, and we will also follow FDA, CDC and other public health guidance, and provide updates.

No. The vaccine does not contain live or dead versions of the virus, so it cannot transmit COVID-19 and does not alter human DNA.

While the studies haven’t indicated how long protection will last, the FDA predicts it to be effective months or maybe even years. Booster doses may be required in the future. Experts are continuing to study how long the protective effect lasts.

Stopping a pandemic requires using all the tools available. Vaccines work with your immune system so your body will be ready to fight the virus and reduce or eliminate illness if you are exposed. Other steps, like covering your mouth and nose with a mask and staying at least six feet away from others, help reduce your chance of being exposed to the virus or spreading it to others.

The latest guidelines from the CDC state those who are fully vaccinated do not need to wear masks in most settings. However, it's important to note that the vaccines are not perfect and a small percentage of those vaccinated may still be susceptible to COVID-19. In addition, masks may still be required in some circumstances such as at grocery stores or sporting events.

Remember, vaccines are just one way to help stop the spread of COVID-19. Wearing a mask, social distancing and hand washing are other tools that we can use to help end this pandemic.

If you received the COVID-19 vaccine and are exposed to someone with COVID-19, the CDC states you do not need to quarantine if you:

1. Are fully vaccinated, which means it has been at least two weeks since your second dose.
2. Are within three months of getting the last dose in the series.
3. Have remained asymptomatic since your exposure to COVID-19.

You should also check with your workplace or school system if you have questions about their policies concerning positive COVID-19 tests.

Yes. The vaccine is not 100% effective, so there is still a chance you can get COVID-19, and then spread it to others. That’s why it’s so important to continue to wear a mask and practice social distancing even after you have gotten both doses.

COVID-19 vaccine breakthrough is defined as having a positive test for COVID-19 at least 14 days after completing both doses of a two-dose COVID-19 vaccine (Pfizer or Moderna) or one dose of the Janssen (J&J) vaccine.

We recommend that you contact your primary care provider to notify them of your positive COVID-19 test and the date of your last COVID-19 vaccination. Your primary care provider will then notify the Connecticut Department of Public Health (DPH) about the possibility of vaccine breakthrough. This is part of a national effort directed by the Centers for Disease Control and Prevention (CDC) to monitor COVID-19 infections among vaccinated people.

If it has been more than 14 days since you completed your vaccination, it is very unlikely that you will develop severe symptoms or require hospitalization due to COVID-19. However, you should still monitor any symptoms that develop and seek medical evaluation if your symptoms worsen. You will also need to self-isolate according to the CDC guidelines until ten days have passed since the date of your positive COVID-19 test, and any COVID-19 symptoms are improving, and you have gone at least 24 hours with no fever and no fever-reducing medications.

The latest recommendations from the CDC state those who are fully vaccinated can safely travel within the U.S. However, it's important for fully vaccinated individuals to continue to wear a mask and practice social distancing in public spaces. If you were exposed to COVID-19, are sick or test positive for the virus, you should not travel. 

Please note, many countries are still listed as having a high-risk. Learn more about countries with a CDC Level 3 COVID-19 travel notice.

COVID-19 and the flu are completely different. The flu vaccine does not protect you from becoming infected with COVID-19, so you should get both vaccines, if available. One of the benefits from getting a flu vaccine in addition to the COVID-19 vaccine, is that a recent study suggests people who received the flu vaccine faced a lower risk for being hospitalized if they got COVID-19.

Side effects for the three vaccines are usually mild, and at worst are moderate and typically resolve in 1-2 days post-vaccination. Common side effects can include pain at the injection site, muscle aches, headache, nausea, fatigue and sometimes fever.

These side effects are a sign the vaccine is working, and your body is mounting the immune response it needs to in order to protect you from severe COVID-19 infection. These side effects are much less severe than actual COVID-19 infection and are not life-threatening.

Concerns about developing infertility, Bell's palsy, alterations of the DNA, and autoimmune conditions are unfounded. These are not side effects of the vaccine and have not occurred more frequently than normal among those who have received the vaccine.

As with any medicine, there is a very remote chance of a vaccine causing a severe allergic reaction, other serious injury, or death. No severe side effects have been reported from the clinical trials.

Learn more about the differences between the vaccines

Yes. Vasovagal reactions, such as fainting or a feeling like you are going to pass out, can happen in different situations including receiving a vaccine, getting your blood drawn, etc., and are considered benign (i.e., there are no long-term consequences). An individual can and should receive their second dose to be fully protected, but they should indicate this to the vaccinator so that they can be vaccinated in a recliner or recumbent position. 

Based on the clinical trials for the Pfizer and Moderna vaccines, the second dose results in a higher number of side effects (including fever and chills, headaches, body aches, fatigue and nausea) but there is no evidence for more serious side effects or risk of anaphylaxis from receiving the second dose. 

These side effects indicate that the internal process of stimulating the immune system and making antibodies against COVID-19 is taking place as a result of receiving the vaccine, and are not as concerning as the more severe symptoms of COVID-19 infection and are not considered to be life-threatening.

No, don't skip the second dose. You may wish to consider taking Tylenol and/or Benadryl when getting your next dose. You might also want to plan for your second dose 2-3 days before you are schedule to work in case you need to stay at home. If you take Benadryl, you should not drive as it causes drowsiness. 

Routine use of prophylactic (preventive) pain medicines before you get your vaccination is not currently recommended, as information on the impact on vaccine-induced antibody responses is not available at this time. However, if you experience side effects after receiving your vaccination (such as swelling or pain at the vaccination site, fever, headaches, or body aches) then taking an over-the-counter pain medicine (such as Tylenol) may be helpful in managing those symptoms.

Common side effects indicate your body is making an immune response to the vaccine and they should go away within 1-2 days. Some ways to minimize mild side effects include:

• Use an ice pack or cool, damp cloth to help reduce redness, soreness and/or swelling at the place where the shot was given.
• A cool bath can also be soothing.
• Drink liquids often for 1-2 days after getting the vaccine.
• Take an over the counter pain reliever unless you have any specific contraindications. 

Learn more

Symptoms that are side effects of the vaccine typically go away on their own within a couple of days and are a sign that the immune system is working. If side effects continue for more than 72 hours, they should be reviewed by a clinician. For severe side effects, contact your doctor or Urgent Care.

The vaccine does not cause respiratory symptoms or a loss of taste or smell, which are sometimes seen with a true COVID-19 infection. For these symptoms and/or if you have had a known or suspected COVID-19 exposure within the past 10 days, you should call your doctor.

Swollen lymph nodes in the underarm on the same side as the injection site may occur after COVID vaccination and may persist for up to several weeks. While swollen lymph nodes due to the vaccine are not worrisome, they may be detected on a routine screening mammogram and might need additional testing. If possible, try to schedule both doses of your COVID vaccine series before an upcoming mammogram. If that is not possible and if it will not result in undue delays, try to schedule your routine screening mammogram approximately 4-6 weeks after your second dose of a COVID-19 vaccine.

We are offering the vaccine to individuals who are pregnant or breast-feeding. Based upon what we know at this time, pregnant women are at an increased risk for severe illness from COVID-19. Additionally, pregnant women with COVID-19 infection might be at an increased risk for other adverse pregnancy outcomes such as pre-term birth and stillbirth.

Given the absence of detailed study of these vaccines during pregnancy, pregnant and breastfeeding individuals should discuss the risks and benefits of vaccination with their obstetrician, pediatrician, and/or midwife.

We are aware of concerns in the public about fertility after the COVID-19 vaccine. However, these concerns are unfounded. The safety data reported to the FDA for the Pfizer vaccine demonstrated that equivalent proportions of individuals became pregnant in the vaccine groups as the placebo groups. Among the people who did get pregnant in the studies, there were no self-reported pregnancy related adverse events in the groups that received vaccine. At this time, we support offering the vaccine to individuals planning pregnancy.

We are offering the vaccine to individuals who are breastfeeding, who should discuss this with their pediatrician to help weigh the risks and benefits of getting vaccinated. We will continue to review additional data and guidelines on the safety and effectiveness of vaccination against COVID-19 for pregnant/breastfeeding individuals as they become available.

The only vaccine that received Emergency Use Authorization from the FDA for those 12 and older is the Pfizer vaccine. The Moderna and Johnson & Johnson vaccines are currently for those 18 and older.

However, clinical trials are underway with younger children, so we hope to learn more about the vaccine's safety and efficacy in those participants in the coming months. Read answers to some commonly asked questions about the vaccine and those 12 and older here. 

Yes. Patients with comorbidities have the presence of more than one medical condition. We know that people with underlying health conditions are at a higher risk for getting more severe cases of COVID-19. That’s why it’s important that those individuals get vaccinated as soon as they are eligible to do so.

The vaccine helps to reduce both the symptoms of COVID-19 and the possibility of getting the virus in the first place. Studies on the vaccines included a substantial number of participants with medical conditions and there were not significant safety concerns identified.

According to the CDC, some of the conditions that put people at a higher risk of severe COVID-19 include cancer, obesity, heart conditions such as coronary artery disease, chronic kidney disease and chronic obstructive pulmonary disease. Those with liver disease, cystic fibrosis, asthma, and anyone with an immunocompromised state might be at an increased risk for severe illness as well.

Anyone who is at a higher risk of getting severe cases of COVID-19 should do everything they can to reduce the chance of getting the virus. The best way to protect yourself is by getting vaccinated. If you have any concerns about your health, contact your primary care physician.

If you previously have had an anaphylactic reaction to another vaccine or medication, you still may receive the COVID-19 vaccine, but we will ask you to notify the staff and be monitored in the vaccination clinic for 30 minutes after you receive your injection.

However, the FDA is recommending that individuals who have severe allergic reactions to any ingredients of a vaccine should not receive that vaccine. The ingredients of each vaccine are listed in the FDA facts sheets which can be accessed here.

There are safety protocols in place at our clinics to quickly address severe allergic reactions following vaccine administration. Also, if you experience an allergic reaction to a vaccine, you may be referred to an Allergist for evaluation.

For Pfizer or Moderna vaccines: if you experience an anaphylactic reaction to a first vaccine dose, you should not receive the second dose and instead consider getting the Janssen (J&J) vaccine.

You may have heard that children are less likely to develop severe cases of COVID-19, and therefore think it's unnecessary for them to get vaccinated. However, they can still get very sick and even require hospitalization. 

The best way to protect kids is for them to get vaccinated. Vaccination is the best thing we can all do to help end the pandemic and return to normal activities like in person learning and after school activities. Therefore we encourage everyone who is eligible to get the vaccine, including those who are 12 and older. 

If you are concerned about a specific health condition or allergy, please contact your pediatrician to discuss your options. 

No, but if you are receiving immunosuppressant medication (such as steroids, certain drugs to treat inflammatory conditions, current cancer therapy, etc.), you should talk with your prescribing clinician as the medication might interfere with your body’s ability to develop a full immune response to the vaccine. They may be able to help you better time when you get vaccinated.

Unless you have had an allergic reaction to a previous dose of the type of COVID-19 vaccine you are planning to get or are allergic to one of the ingredients in the vaccine (e.g., polyethylene glycol or polysorbate), you should be able to get the vaccination. If you have concerns regarding your history of allergic reactions, you should discuss this with your regular clinician before getting vaccinated.

The rate of allergic reactions in the clinical data was very, very low.

However, we recommend individuals discuss the risks and benefits of vaccination with the allergist/immunologist before scheduling their vaccination. You should notify the staff at our vaccination site of any prior allergic reaction before receiving the COVID-19 vaccine.

All vaccination sites will be prepared to respond to any allergic reactions in the unlikely case that they occur.

Yes, immunocompromised individuals should get vaccinated. Individuals with immunocompromising conditions (such as HIV or who have received an organ or stem cell transplant) or who take immunosuppressive medications or therapies might be at risk for increased severe COVID-19 disease.

The current mRNA COVID-19 vaccines do NOT contain live virus and cannot cause COVID-19, so there are no specific safety concerns in immunocompromised individuals.

However, they may wish to discuss COVID-19 vaccination with their specialist if they have specific questions or concerns. Although the effectiveness of COVID-19 vaccination may be reduced in an immunocompromised individual, such individuals are still advised to receive the COVID-19 vaccine if they do not have any other contraindications for vaccination. 

The current CDC guidance allows for consideration of the Janssen (J&J) COVID-19 vaccine (at 28 days after the mRNA vaccine was given) in this situation as it uses a different mechanism to stimulate the immune system and has different components from the mRNA vaccines.

This is best done in consultation with an allergist. Please contact your primary care provider or other provider who can assist you with a referral to an allergist. If the allergist determines that it is safe for you to receive the Janssen (J&J) vaccine in place of the second dose of the Pfizer or Moderna vaccine, please be sure you are selecting that dose when you schedule your appointment.

Note: A “severe, immediate vaccine allergy” is defined as anaphylaxis, hives, swelling of face/lips, or respiratory distress (e.g., wheezing, stridor) occurring within 4 hours of receiving a prior dose of a Pfizer or Moderna COVID-19 vaccine.

If you have a severe allergy to polysorbate then vaccination with Janssen (J&J) COVID-19 vaccine is CONTRINDICATED.

However, the Pfizer or Moderna COVID-19 vaccines do not contain polysorbate so either vaccine is an option for COVID-19 vaccination. Recent guidance by the CDC does allow vaccination of individuals with a severe polysorbate allergy to receive either the Pfizer or Moderna vaccine after a review of risks. This is best done in consultation with an allergist. Please contact your primary care provider or other provider who can assist you with a referral to an allergist.

If an allergist determines that it is safe for you to receive the Pfizer or Moderna vaccine, make sure that is the vaccine you are getting.

Note: A “severe allergy” is defined as anaphylaxis, hives, swelling of face/lips, or respiratory distress (e.g., wheezing, stridor).

If you have a severe allergy to polyethylene glycol (PEG), then vaccination with either the Pfizer or Moderna COVID-19 vaccine is CONTRAINDICATED.

However, the Janssen (J&J) vaccine does not contain PEG so it is an option for COVID-19 vaccination. Recent guidance by the CDC does allow vaccination of individuals with a severe PEG allergy to receive the Janssen (J&J) vaccine after a review of risks. This is best done in consultation with an allergist. Please contact your primary care provider or other provider who can assist you with a referral to an allergist if you need one.

If an allergist determines it is safe for you to get the J&J vaccine, make sure that is the vaccine you are getting.

Note: A “severe allergy” is defined as anaphylaxis, hives, swelling of face/lips, or respiratory distress (e.g., wheezing, stridor).

Yes, you should go ahead and get your COVID vaccine unless have a known allergy to the vaccine. To ensure safety for individuals with an increased risk of bleeding following an injection, the following are expert guidelines to help ensure your safety:

- For individuals receiving prolonged anticoagulation or antiplatelet therapy (such as warfarin and other prescribed anticoagulant therapy, including daily aspirin): 

• These medications are considered to present only a low risk of complications related to prolonged bleeding after an injection.
• After the injection, you should apply firm pressure over the site of the injection for 5 minutes.

- For individuals with a history of Hemophilia (or other severe bleeding disorder) or platelet count less than 50,000/uL:

First consult with your specialty physician for guidance prior to vaccination. If that physician agrees that the benefit of the intramuscular (IM) vaccination outweighs possible risks, the following steps at the time of vaccination are recommended:

• If you take replacement clotting factors, then the IM vaccination should be administered as soon as feasible after the dose of the clotting factor.
• Nursing staff who routinely perform IM injections are preferred to administer the vaccination.
• An ice pack should be applied to the site before the injection.
• After the injection, you should apply firm pressure over the site of the injection for 5 minutes.

Blood clots involving blood vessels in the brain, abdomen, and legs along with low levels of platelets (blood cells that help your body stop bleeding), have occurred in a small number of people who have received the Janssen COVID-19 Vaccine. In people who developed these blood clots and low levels of platelets, symptoms began approximately one to two-weeks following vaccination. Most people who developed these blood clots and low levels of platelets were females ages 18 through 49 years. The chance of developing blood clots with low platelets after vaccination with the Janssen J&J) vaccine is extremely rare (less than one in a million overall):

• The risk among women 18-49 years old is 7 cases per million Janssen (J&J) vaccines given
• The risk among women 50 years and older is 0.9 cases per million Janssen (J&J) vaccines given 
• Only one case has been reported among men who received the Janssen (J&J) vaccine.

Women who are younger than 50 years may receive the Janssen (J&J) vaccine. However, they should be aware of the rare risk of a specific syndrome of blood clots and low platelets (known as Thombosis and Thrombocytopenia Syndrome or TTS) which has been observed in a very small number of women following vaccination with the Janssen (J&J) vaccine. Although the overall risk is very low, the risk of TTS was higher in women younger than 50 years compared to older women:

• The risk among women 18-49 years old is 7 cases per million Janssen (J&J) vaccines given.
• The risk among women 50 years and older is 0.9 cases per million Janssen (J&J) vaccines given.

There are other FDA-authorized COVID-19 vaccines (i.e. the mRNA vaccines made by Pfizer and Moderna) that have not been found to increase the risk of TTS.

While pregnancy, itself, can make women more susceptible to developing blood clots, pregnancy is not known to make women more susceptible to the specific syndrome of blood clots and low platelets that has been observed in a very small number of women following vaccination with the Janssen (J&J) vaccine. There were no pregnant women among those who developed this syndrome following vaccination.

While the period during and after pregnancy can make women more susceptible to developing blood clots, women who have recently given birth are not known to be more susceptible to the specific syndrome of blood clots and low platelets that has been observed in a very small number of women following vaccination with the Janssen (J&J) vaccine.

Yes. You do not need to stop taking these medications prior to getting the Janssen (J&J) vaccine.

While oral contraceptives and hormone therapy can make people more susceptible to developing blood clots, women who are on these hormones are not felt to be more susceptible to the specific syndrome of blood clots and low platelets that has been observed in a very small number of women following vaccination with the Janssen (J&J) vaccine.

Some people with a specific heparin allergy, known as Heparin-Induced Thrombocytopenia or HIT, should not get the Janssen (J&J) vaccine. If you think you may have an allergy to heparin, it is best to check with your doctor before getting this vaccine or to get an mRNA COVID-19 vaccine (made by Pfizer or Moderna) instead.

No. There is no need to start aspirin or anticoagulant medication before the Janssen (J&J) vaccine unless you are prescribed this for another reason.

Talk with your healthcare provider, call your local or state health department or contact the Centers for Disease Control and Prevention at 1-800-232-4636 (1-800-CDC-INFO) or visit CDC’s vaccine website: www.cdc.gov/coronavirus/2019-ncov/vaccines.

YNHHS will be updating and distributing more generally asked questions and answers as more information becomes available.