Communicating About COVID-19 Vaccination

(Updated September 29, 2021)

COVID-19 vaccines currently available for use either have an Emergency Use Authorization (EUA; in the U.S.) or an Interim Order (Canada). See our chart, COVID-19 Vaccines, for a comparison of available COVID-19 vaccines. The FAQ below answers common questions your patients may have about COVID-19 vaccination and includes talking points and strategies to address COVID-19 vaccine misconceptions.


Answer/Pertinent Information

COVID-19 vaccines are being approved more rapidly than other vaccines. How can you reassure patients about this expedited approval process?

COVID vaccines have been developed at a more rapid pace than what is normally seen with other vaccines. This does NOT mean safety steps have been skipped.34 The development process has been expedited because of the pandemic (e.g., early funding to ramp up manufacturing, overlapping phases of trials).34

  • Operation Warp Speedb (U.S.) and International Coalition of Medicines Regulatory Authorities (ICMRA [Canada]) are helping ensure the rapid development process still adheres to safety and efficacy standards.11,28

COVID-19 vaccines are going through the same RIGOROUS approval process as other approved vaccines. Data are reviewed/analyzed by independent experts (i.e., not scientists employed by the manufacturer). The independent reviewer recommendations are then presented to the approving agency (e.g., FDA, Health Canada).50

Reassure patients that COVID-19 vaccine safety is a top priority.21,27 COVID-19 vaccines are being studied through phased testing to ensure safety and efficacy before they are made available to the public.

  • Safety monitoring is ongoing. Explain that in addition to standard monitoring (e.g., vaccine adverse event reporting system [VAERS]) additional monitoring is being done.
    • For example, in the U.S., V-SAFEa is a new smartphone-based healthcare checker to use after vaccination. It will use CDC text messages and web-based surveys to check in with recipients of a COVID-19 vaccine.17

Which patients were excluded from early COVID-19 vaccine trials?

Some early COVID-19 vaccine trials’ exclusion criteria included:

  • acutely ill or febrile
  • known history of SARS-CoV-2 infection or use of investigational meds to prevent SARS-CoV-2 infection
  • bleeding disorders involving contraindications to IM injections
  • immunosuppression (e.g., HIV, active hepatitis B or C infection, receiving cytotoxic therapy or systemic steroids for cancer or autoimmune disease)

Some of the COVID vaccines are utilizing new types of technology. How can you reassure patients these newer vaccines are safe?

Many COVID-19 vaccines are new types of vaccines (e.g., messenger ribonucleic acid [mRNA], viral vectors).22,35

  • Explain to patients how COVID-19 vaccines work.22,35,73
    • mRNA vaccines (e.g., mRNA-1273 [Moderna], BNT162b2 mRNA [Pfizer/BioNTech]) give our cells a blueprint for how to make a piece of a SARS-CoV-2 “spike” protein (note this piece of the SARS-Co-V-2 “spike protein” is harmless to the vaccine recipient). This triggers an immune response. Once the blueprint is delivered, the messenger (mRNA) is broken down.
    • Vector vaccines (e.g., ChAdOx1-S [AstraZeneca], Ad26.COV2.S [Janssen/J&J]) use a weakened version (e.g., non-replicating, modified) of a different live virus with a viral vector (genetically inserted material from COVID-19). The virus used poses no threat of causing illness in humans because of the modification or because the type of virus cannot cause disease in humans. The viral vector teaches the vaccinated person’s body to build cells to fight COVID-19.
  • Explain that available COVID-19 vaccines do NOT contain the SARS-CoV-2 virus.22,35,73
  • Reassure patients that available COVID-19 vaccines do NOT affect a person’s genetic material (DNA).6,22,73
  • Reassure patients that scientists have been studying mRNA and viral vector vaccines for >15 years.34,73 Even though COVID-19 vaccines will be the first mRNA and viral vector vaccines to come to market, it is not new science.

What are some talking points to use with patients who may be hesitant to get vaccinated for COVID-19?

Remind patients about the benefits of COVID-19 vaccination. Vaccination may:16

  • reduce illness severity if you become infected with COVID-19.
  • protect friends, family, co-workers, and close contacts from getting COVID-19.
  • allow people to start doing more (e.g., eating at restaurants, gathering with others who are vaccinated without masks.)

Explain that the COVID-19 vaccine is one important tool in the toolbox to end the pandemic.16

  • Social distancing and masks reduce the chance of exposure to the coronavirus that causes COVID-19.16
  • Vaccination gets your immune system ready to fight COVID-19 infection if exposed.16
  • Vaccination is also an important step in the development of herd immunity.21
    • Herd immunity is when it is unlikely that a bacteria or virus can spread and cause disease because a large enough proportion of people are protected or considered immune.21 More data are needed to know how many people need to be protected to achieve herd immunity against COVID-19.21 Some predict that about 75% to 80% of the U.S. population would need to be vaccinated to achieve herd immunity.32
    • Caution patients that relying on natural immunity to achieve herd immunity to COVID-19 would mean hundreds of millions of people would have to recover from COVID-19; and during the time it would take for that many to recover, many more people could experience COVID-19 complications or death.51

Encourage vaccination as the safer path toward immunity.

  • There is no way to predict COVID-19 infection severity for anyone, and infections can be fatal.4,12,16
  • COVID-19 infection has been associated with long-term consequences, even in young healthy people (e.g., lung, heart, and memory problems; mood changes; kidney damage).4,5
  • Tell patients that we don’t know how long natural immunity (antibodies from exposure to the virus through infection) or vaccine-induced immunity (antibodies from vaccination) lasts.3 Natural immunity varies in duration. Explain that limited vaccine data suggests vaccine-induced immunity may last longer.46

What age groups should receive a COVID-19 vaccine?

Pfizer/BioNTech/Comirnaty vaccine: FDA-approved for ages ≥16 years (can be used under EUA for ages 12 to 15 years) and Health Canada-approved for ages ≥12 years.20,68,69

Moderna vaccine (SpikeVax [Canada]): authorized for ages ≥18 years (U.S.); Health Canada-approved for ages ≥12 years.49,125

AstraZeneca/COVISHIELD/Vaxzevria (Canada only) and Janssen/J&J vaccines: authorized for ages ≥18 years.49,69,81,82

Generally, children outside of these authorized age groups should not receive a COVID-19 vaccine.49,69

What do we know about safety and efficacy of COVID-19 vaccine in children?

At the time of publication, only Pfizer/BioNTech/Comirnaty vaccine is authorized for use in adolescents as young as 12 years old in the U.S. In Canada, Pfizer/BioNTech/Comirnaty and Moderna (SpikeVax) vaccines are Health Canada-approved for use in adolescents as young as 12 years old.69,105

Initial data suggest the Pfizer/BioNTech mRNA vaccine at a 10 mcg per dose, two-dose series (separated by 21 days) appears safe and effective in children between five and 11 years old (i.e., non-inferior immune response compared to a 30 mcg two-dose series in people 16 to 25 years old). An application for EUA is planned based on this data.103

  • Data are being collected for use in younger children, as young as six months old.102,103

Encourage vaccination in eligible adolescents. Children and teens can get COVID-19, including severe cases and complications of COVID-19 (e.g., "long-haul" COVID, Multisystem Inflammatory Syndrome in Children [MIS-C]).75,93

  • About one-third of hospitalized children with COVID-19 require care in the intensive care unit (ICU).72
  • More than half of children who had COVID-19, still have at least one symptom lasting ≥120 days.93

Follow laws and regulations regarding parental consent for childhood vaccination. In the U.S. state-specific minor consent laws can be found at

What do we know about the efficacy of COVID-19 vaccines against COVID-19 variants?

Data suggest that currently available COVID-19 vaccines are highly effective at preventing severe disease and death against SARS-CoV-2 variants (including B.1.617.2 [Delta variant from India]).110

However, fully vaccinated people can experience breakthrough infections and then spread the virus to others, though it appears that vaccinated people spread the SARS-CoV-2 virus for a shorter time compared to unvaccinated people.110

Variants of the SARS-CoV-2 virus are continuing to emerge. Studies are ongoing to assess the need for booster doses or “second-generation” vaccines to continue to provide protection.111

  • “Mixed-series” vaccinations (using an mRNA vaccine and a viral vector vaccine) are being evaluated.112
    • Though more data is needed to confirm, the theory behind a using “mixed-series” vaccinations is that it may lead to a stronger immune response than two doses of the same vaccine.112,123

What are the expected short-term adverse effects with COVID-19 vaccination?

Be transparent that patients may experience short-term adverse effects after vaccination (i.e., don’t downplay these). For other two-dose vaccines, this has been helpful to ensure patients return for their second dose (e.g., Shingrix vaccine).

  • Younger patients may be more likely than older patients to experience side effects.41
  • Most patients can expect mild to moderate injection-site pain or soreness (redness and swelling are less likely).15,18,33,41
    • Some patients may experience “COVID arm” (large localized area of redness; may be tender or warm) about a week after an mRNA COVID-19 vaccine. This usually goes away in a few days. Encourage completing the vaccine series. Can use cold compresses for symptom relief. Consider using the other arm for the second dose.94
  • Many patients experience systemic reactions (more likely with the second dose), within ~2 days of vaccination. These usually go away within a day or two.33 This is a normal response to a vaccine and means the body is building antibodies to prevent infection.7,41
  • Early data suggest that reactions after a third mRNA COVID-19 vaccine dose (i.e., additional dose for patients who are immunocompromised) are similar to reactions from the second dose and most symptoms seem mild to moderate.52
  • Example systemic reactions COVID-19 vaccines include:1,41,61,79,81,82
    • fatigue/malaise/headache
    • fever/chills
    • myalgia/arthralgia
  • Syncope or fainting has been reported after nearly all vaccines (not just COVID-19 vaccines).

Temporary post-vaccination lymphadenopathy (swollen lymph nodes in neck or underarm) after receiving an mRNA COVID-19 vaccine may lead to unnecessary breast biopsies. See for guidance on breast imaging after vaccination and administering vaccine to patients with cancer.88-90

What can patients do to minimize expected vaccine adverse effects?

Help patients reduce and prepare for adverse effects. For example:

  • CDC and Health Canada support use of antipyretic or analgesic meds (e.g., acetaminophen, ibuprofen) AFTER VACCINATION TO TREAT SYMPTOMS from a COVID-19 vaccine. However, routine use of prophylactic acetaminophen before or after vaccination with a COVID-19 vaccine is not recommended until we know more about the impact on immunogenicity.49,69
  • Suggest that patients get vaccinated when they will have a few days to rest and recover (i.e., on a Friday if they don’t work weekends). Similarly, healthcare facilities may want to stagger staff vaccinations in order to minimize personnel shortages in case people are unable to work for a day or two after vaccination.29

Have there been serious or unusual adverse effects from COVID-19 vaccination?

Serious adverse effects from COVID-19 vaccination seem extremely rare, and monitoring is ongoing.4 If a safety issue is identified, it will be evaluated to see if it is related to the vaccine.4

  • There have been reports of severe allergic reactions, including possible anaphylaxis, after receiving mRNA or viral vector COVID-19 vaccines.45,47,58,76,82,91 Anaphylaxis is a known, but rare side effect with any vaccine.45,76
  • Rare/serious side effects noted with mRNA COVID-19 vaccinesinclude:
    • The rate of Bell’s palsy seen after COVID-19 vaccination was NOT more than is expected in the general population. Patients who have previously had Bell’s palsy may receive a COVID-19 vaccine.1,8,70
    • Myocarditis and pericarditis have been reported almost exclusively after an mRNA vaccine.119,122 In the U.S. these cases have typically occurred after the second dose, been mild, resolved with medications, and are seen in male adolescents and young adults (e.g., ≥16 years old).119 Cases in Canada were more evenly distributed after first or second doses.122 Reports will continue to be investigated.119,122
  • Rare/serious side effects noted with viral vector COVID-19 vaccines include:
    • Transverse myelitis was noted in an ChAdOx1-S (AstraZeneca/COVISHIELD/Vaxzevria viral vector vaccine) trial. Monitoring for neurologic events will continue and will be provided to experts for review.44
    • Guillain-Barre syndrome (GBS):70,82,124 A history of GBS is NOT a contraindication to receiving a COVID-19 vaccine70,82
    • There are reports of rare blood clots (some involved bleeding, some were fatal) occurring along with a low platelet count (e.g., cerebral venous sinus thrombosis [CVST]) after receiving a dose of the AstraZeneca/COVISHIELD/Vaxzevria (authorized in Canada; seen more commonly in males after the first dose) and Janssen/J&J (authorized in the U.S.; seen more commonly in females <60 years old) vaccines.19,25,57,97-100,122 It’s being referred to as thrombosis with thrombocytopenia syndrome (TTS).98 However, the risk of clotting is much higher with SARS-CoV-2 infection.95
      • These rare blood clots along with low platelets may require different treatment than typical blood clots. An immune response to the vaccine may promote clotting, similar to what occurs with autoimmune heparin-induced thrombocytopenia (HIT). Treating with heparin or low-molecular weight heparin (LMWH) can be dangerous, unless HIT has been ruled out.100
        • Only treat these rare clots and associated thrombocytopenia with heparin or LMWH if heparin-induced platelet antibody testing is negative.100
        • If HIT results are positive or not available, work with hematology as IV immune globulin may be used.100
      • Encourage patients who develop symptoms suggestive of blood clots or low platelets after receiving Janssen/J&J COVID-19 vaccine or the AstraZeneca/COVISHIELD/Vaxzevria COVID-19 vaccine (Canada), especially within three weeks of vaccination, to seek medical care right away. Symptoms can include:97,98
        • symptoms of a blood clot (e.g., shortness of breath, abdominal or leg pain, redness, warmth, swelling)
        • neurologic symptoms (e.g., severe headache, blurred vision)
        • new or easy bruising
        • petechiae (tiny red spots on the skin)
What are contraindications or precautions to receiving a COVID-19 vaccine?

Contraindications to a COVID-19 vaccine includes:10,20,38,49,58,69,79,80,96,126

  • history of a severe allergic reaction (e.g., anaphylaxis) after a dose of the same type of COVID-19 vaccine (e.g., mRNA, viral vector).
    • Patients who experience anaphylaxis after an mRNA COVID-19 vaccine should NOT receive any other mRNA COVID-19 vaccine.
    • Patients who experience anaphylaxis after a viral vector COVID-19 vaccine should NOT receive any other viral vector COVID-19 vaccine.
  • history of an immediate allergic reaction of any severity within four hours (e.g., wheezing, hives) to:
    • a previous dose of the COVID-19 vaccine
    • any component of the vaccine such as:
      • polyethylene glycol (PEG) (an ingredient in mRNA vaccines)
      • polysorbate (potentially cross-reactive with PEG and an ingredient in viral vector vaccines)
  • A contraindication to an mRNA vaccine is a precaution to a viral vector vaccine (and vice versa).
  • Consider referrals to an allergist-immunologist with the following precautions to COVID-19 vaccination:49,69 (In the U.S. consider using the Clinical Immunization Safety Assessment [CISA] consultation by phone or online. Details can be found at
    • People with a contraindication to an mRNA COVID-19 vaccine have a precaution against viral vector COVID-19 vaccines (and vice versa).
      • If one type of COVID-19 vaccine is given (despite precautions) because of a contraindication to the other type of COVID-19 vaccine:47,49,69
        • give the COVID-19 vaccine ≥ 28 days after the contraindicated COVID-19 vaccine (if one was given).
        • obtain informed consent (Canada).

Other precautions to be aware of, patients with a history of:

  • rare blood clots associated with a low platelet count or HIT should only receive the AstraZeneca/COVISHIELD/Vaxzevria COVID-19 vaccine if the benefit outweighs the risk.79,96
  • major venous or arterial clots with thrombocytopenia after the first dose of the AstraZeneca/COVISHIELD/Vaxzevria vaccine should not receive a second dose.79,96
  • capillary leak syndrome should not receive the AstraZeneca/COVISHIELD/Vaxzevria COVID-19 vaccine.79,96

How long should patients be monitored after receiving a COVID-19 vaccine?

Monitor patients receiving a COVID-19 vaccine for 30 minutes if they have a history of severe allergic reaction (e.g., anaphylaxis) to anything, an immediate allergic reaction of any severity to a vaccine or injectable medication, or have a contraindication to the other type of COVID-19 vaccine.47,49,69

Monitor all other patients for 15 minutes after receiving a COVID-19 vaccine(including patients with a history of severe allergies to foods, pets, latex, and oral medications [excluding oral med allergies that are related to polysorbate or PEG]).47,49,69

Is the single-dose viral vector COVID-19 vaccine as effective as two-dose COVID-19 vaccines?

There are no head-to-head data directly comparing the available COVID-19 vaccines.62,77

Experts believe that the single-dose Ad26.COV2.S Janssen/J&J COVID-19 vaccine is NOT inferior to the two-dose mRNA vaccines. Differences in efficacy rates are likely due to differences in when and where trials were conducted and circulating variants.62,77

  • All currently available vaccines in U.S. and Canada are good vaccines.62,69,77 All four vaccines have documented efficacy >70% against hospitalization for COVID-19 (data from March to August 2021):69,129
    • Pfizer/BioNTech/Comirnaty: 88%
    • Moderna (SpikeVax [Canada]): 93%
    • Janssen/J&J: 71% (Note: preliminary data suggest a booster dose of the Janssen/J&J vaccine significantly increases antibody levels when given two or six months after the initial dose.130)
    • AstraZeneca/COVISHIELD/Vaxzevria: comparable data unavailable. Note AstraZeneca is authorized as a two-dose series with 100% efficacy with follow-up duration of up to 79 days after second dose (data as of November 2020).

The CDC does not give preference to any particular COVID-19 vaccine.128

Canada gives preference to mRNA COVID-19 vaccines, but recommends a viral vector vaccine when an mRNA vaccine is contraindicated or not accessible.69

What are strategies to encourage patients to return for the second dose of a two-dose COVID-19 vaccine?

Stress the importance of completing the vaccination series with the same vaccine (COVID-19 vaccines are NOT interchangeable), if more than one dose is needed.36,49

  • Exception to this in Canada:118 either an AstraZeneca/COVISHEIELD or an mRNA vaccine may be used for the second dose in a vaccine series that started with AstraZeneca/COVISHIELD/Vaxzevria due to the risk of vaccine-induced immune thrombotic thrombocytopenia after AstraZeneca/COVISHIELD/Vaxzevria vaccines.
  • Give patients vaccine cards with product specific information about the vaccine they received and second-dose reminders/date to return.48
  • Consider searching immunization registries if patients received their first dose somewhere else and they are not sure which vaccine they received. U.S. subscribers can review our Immunization Registry FAQs, to learn more about registry capabilities.
  • In RARE circumstances, if the previous vaccine product cannot be determined or is no longer available, any available mRNA COVID-19 vaccine may be given with a minimum interval of 28 days between doses to complete the mRNA COVID-19 vaccination series.49,118
    • If a dose of DIFFERENT mRNA vaccine is mistakenly given, instead of using the same product for the entire series, no additional doses are currently recommended.49

Help patients understand why two doses are used for many vaccines.

  • Vaccines work by teaching the body to recognize and fight a specific foreign substance (e.g., virus, bacteria).26
  • Vaccines do NOT replicate in our bodies like viruses and bacteria do.26
  • Think of the first dose as a primer. The body is starting from scratch to recognize and fight the virus.26
  • Think of the second dose as a booster. It provides the body another opportunity to learn how to respond, and to create even more memory cells against the virus.26

Consider these tips to improve the likelihood patients will return for second doses:

  • Make a strong recommendation to return for second doses. This can be a powerful motivator.23
  • Utilize reminder systems within your computer systems.23
  • Have patients schedule their appointment for their second dose when they receive their first dose
  • Use technology to remind patients (e.g., apps, texts, emails, phone calls)

See our toolbox, Medication Adherence Strategies, for other adherence ideas.

What happens if the second COVID-19 vaccine dose is not given on schedule (too soon or too late)?

To get the most benefit from vaccination, adhere to recommended vaccine dosing intervals.53,71

  • In general, when vaccine doses are given too close together, this can lead to a smaller immune response to the vaccine compared to when doses are given according to recommended schedules.53
  • For some vaccines, the series needs to be restarted if subsequent doses are delayed too long.54

For COVID-19 vaccines, it is too soon to know how early or late second doses will impact immunity.71 Follow local health authority guidance for specifics in your area. Generally, in:

  • U.S.: Schedule the second dose of the Pfizer/BioNTech/Comirnaty vaccine 21 days after the first dose or the second dose of the Moderna (SpikeVax [Canada]) vaccine 28 days after the first dose. If it is not possible to adhere to these dosing intervals the CDC supports scheduling a second dose for the Pfizer/BioNTech/Comirnaty mRNA vaccine between 17 and 42 days after the first dose,49 and for the Moderna (SpikeVax [Canada]) mRNA vaccine between 24 and 42 days after the first dose).49
    • If a dose is given earlier than day 17 (Pfizer/BioNTech/Comirnaty) or 24 (Moderna [SpikeVax (Canada)]), it is not necessary to repeat.49
    • If a dose is given later than day 21 (Pfizer/BioNTech/Comirnaty) or 28 (Moderna [SpikeVax (Canada)]), give the second dose as soon as possible, preferably within 42 days, as there are limited data beyond 42 days. Even if doses are not given within 42 days, it is not necessary to restart the series.49 Explain that the immune system “remembers” the first dose and responds to the second dose (after the minimum dosing interval) when it is given.67
  • Canada: Ideally give second vaccine doses between:69
    • Pfizer/BioNTech/Comirnaty: 19 to 28 days after the first dose.
    • Moderna (SpikeVax [Canada]): 21 to 28 days after the first dose
    • AstraZeneca/COVISHIELD/Vaxzevria: 28 days (4 weeks) to 12 weeks after the first dose
    • If doses are being delayed in your area, second doses may be delayed up to 4 months from the first dose.

More data are needed before guidance can be given about how to handle early or late second doses of other COVID-19 vaccines being studied.

What does it mean to be fully vaccinated?

People are considered fully vaccinated two weeks or more after receiving either a single dose of Janssen/J&J vaccine or the two-dose series of the other COVID-19 vaccines.14,127

Note: People known to be immunocompromised are NOT required to receive a third additional mRNA dose to be considered fully vaccinated (i.e., in situations where proof of vaccination is required). However, continue to emphasize preventive measures such as wearing a mask and avoiding crowds, even after an additional dose, to limit the risk of exposure.14

We still don’t know how long immunity after vaccination will last.128

What are some talking points about dos and don’ts after patients are fully vaccinated?

It’s okay for fully vaccinated people (see above) with an intact immune system to resume some pre-pandemic activities:78

  • outdoor activities pose minimal risk
  • indoor activities pose low risk in areas with low or moderate transmission (some may choose to wear a mask).

Encourage patients to continue to:48,69,78

  • follow local guidance on necessary precautions.
  • protect themselves and others if traveling (e.g., wear masks on planes or public transportation systems).
  • watch for COVID-19 symptoms, especially if you have been around someone who is sick.

Even when fully vaccinated, continue to wear a mask indoors in areas of substantial or high COVID-19 transmission.78

  • Masks may still be required in some locations based on laws, regulations, or workplace guidance (e.g., hospitals, medical offices).
  • Until we learn more about vaccine efficacy in people with a weakened immune system, even if fully vaccinated, wearing a mask may still be recommended. Advise patients to check with their prescriber.78

Fully vaccinated people who come into close contact with someone with COVID-19 should:78

  • get tested for COVID-19 three to five days after the date of exposure.
  • wear a mask indoors in public until receiving a negative COVID-19 test result or for 14 days from exposure.

Explain we are still learning:9,78

  • about vaccine efficacy against COVID-19 variants.
  • how effective vaccines are in people with a weakened immune system.
  • how long vaccines are protective against COVID-19.

Implementation of safety precautions may change over time as we learn more about the protection provided by COVID-19 vaccination. The number of people who get vaccinated and virus spread in local communities may also play a role in determining this.2

Can a COVID-19 vaccine cause a COVID-19 infection?

No.34 None of the COVID-19 vaccines that are available or are currently in development use the live SARS-CoV-2 virus.6,73

Will COVID-19 vaccination lead to a positive COVID-19 test?

COVID-19 vaccination may lead to a positive test for COVID-19 antibodies (serology tests).6

COVID-19 vaccination will NOT lead to a positive test for active COVID-19 infection (molecular or polymerase chain reaction [PCR] tests and/or antigen tests).6

What do we know about COVID-19 vaccines during pregnancy and lactation?

Pregnant patients are at higher risk for severe illness from a COVID-19 infection or possibly preterm birth.49

There are no safety concerns from animal data with COVID-19 vaccines.49

Preliminary data from pregnant patients who have been vaccinated suggest antibodies are passed to the infant (i.e., via cord blood, breast milk).106 Data indicate that adverse pregnancy and neonatal outcomes (e.g., preterm birth, neonatal death) seem similar to pre-pandemic incidence rates (V-SAFE pregnancy registry data; not a direct comparison).59,101

Reassure patients that experts do NOT expect available COVID-19 vaccines to pose risks to pregnant people; affect development of the placenta; or cause pregnancy loss, still birth, or congenital abnormalities.6,49,66,87

Reassure patients that available COVID-19 vaccines do NOT affect a person’s genetic material (DNA).6,22,56

Experts recommend giving the COVID-19 vaccine to pregnant and lactating patients.49,56,59 Some experts give preference to an mRNA vaccine during pregnancy, due to the possible risk with viral vector vaccines of thrombosis with thrombocytopenia syndrome (referred to as vaccine induced immune thrombotic thrombocytopenia in Canada) and its complex management.69 Note there is no known association between this risk and pregnancy.87

  • Findings from vaccine safety-related databases (including the v-safe pregnancy registry) for mRNA COVID-19 vaccines have not identified any safety concerns for vaccinated pregnant patients or their babies.30

  • Early data suggest that pregnant/lactating people mount a similar immune response to non-pregnant people.55
  • It is NOT necessary to test for pregnancy PRIOR to receiving an authorized COVID-19 vaccine.49,56,59
  • It is NOT necessary to avoid or delay pregnancy AFTER receiving an authorized COVID-19 vaccine.49,56,59,69
  • It is NOT necessary to withhold RhoGAM immune globulin (e.g., Rhogam[U.S.], WinRho S/D). It will NOT interfere with the immune response to an authorized COVID-19 vaccine.59

What do we know about COVID-19 vaccines and menstrual cycles or fertility?

Reassure patients that there are no data (as of August 11, 2021) that any vaccine, including COVID-19 vaccines, leads to fertility problems.13,104

  • Experts recommend the COVID-19 vaccine even if someone is actively trying to conceive or wishes to get pregnant in the future.6

Clarify that COVID-19 vaccines are not live and patients can't "shed" vaccine components. Explain this means there's no way that patients who receive a COVID-19 vaccine can impact the menstrual cycle of others around them.6

Experts recommend females receive a COVID-19 vaccine despite some women reporting menstrual irregularities after receiving a COVID-19 vaccine.107,108 Explain that:6,107-109

  • menstrual irregularities were NOT noted in COVID-19 vaccine clinical trials.
  • there is no biological mechanism explaining how COVID-19 vaccines lead to menstrual irregularities.
  • many things can lead to menstrual irregularities, including changes in diet, sleep, or exercise; stress; illness; etc.

What do we know about safety and efficacy of COVID-19 vaccine in patients who are immunocompromised?

We know that people who are immunocompromised are at risk for severe illness from COVID-19.37

We also know that people who are immunocompromised may have a lesser response to vaccinations.40,92

Per the CDC, it is acceptable to offer a COVID-19 vaccine to patients with immunocompromising conditions (e.g., cancer, HIV, taking an immunosuppressant or biologics).49,70 These are NOT live vaccines.

  • Be sure to counsel these patients about the potential for a reduced immune response.49,70

Limited data suggest:

  • a favorable antibody response in patients with chronic inflammatory conditions (e.g., rheumatoid arthritis, Crohn’s disease) or patients taking hydroxychloroquine or TNF-alpha blockers (e.g., etanercept [Enbrel]).113
    • It’s still too early to know how antibody levels translate into protection against COVID-19.117 
  • a reduced antibody response in hemodialysis patients, solid organ transplant patients, and patients taking methotrexate, mycophenolate, chronic steroids, and Janus kinase inhibitors (e.g., tofacitinib [Xeljanz]).92,114-116,120 
  • vaccination does not lead to autoimmune disease flares (e.g., rheumatoid arthritis, psoriasis, Crohn’s disease).113

Counsel immunocompromised patients, especially patients considered extremely vulnerable, to continue to follow recommendations to reduce risk of infection (e.g., social distancing, hand washing).39,49

Who should receive an additional dose of COVID-19 vaccine AFTER completing the initial vaccination series?

An “additional dose” is a vaccine dose given to people who are not expected to build enough immunity with the initial vaccination series.131

Early data indicate that an additional COVID-19 vaccine dose given to moderately or severely immunocompromised patients may improve antibody response.42,52

In the U.S., give an additional mRNA COVID-19 vaccine dose (after completing an initial two-dose mRNA vaccine series) to people who are considered moderately to severely immunocompromised.49,52

  • Moderna COVID-19 vaccines can be used for patients at least 18 years old.49
  • Pfizer/BioNTech COVID-19 vaccines can be used in patients ≥12 years old under the emergency use authorization (Comirnaty is FDA-approved for patients ≥16 years old).49
  • Use the same vaccine product as the initial two-dose series. If the specific mRNA vaccine used in the two-dose series is unavailable, the other mRNA COVID-19 vaccine may be used.49
  • Separate the third COVID-19 vaccine dose from the final dose of the initial two-dose series by at least 28 days.49
  • More than three doses of an mRNA COVID-19 vaccines are NOT recommended.49
  • Per the CDC, there are not enough data to recommend giving an mRNA COVID-19 vaccine dose as an additional dose to patients who were vaccinated with the Janssen/J&J COVID-19 vaccine.49

In Canada, in patients who are considered moderately to severely immunomcompromised:42

  • Ideally, give a three-dose series (one additional dose for those who have already received two doses) of the same mRNA COVID-19 vaccine.
  • Offer one additional mRNA COVID-19 vaccine dose to patients who have received one-dose viral vector vaccine or a two-dose complete series (with homologous [same vaccine for both doses] or heterologous [different vaccines to complete the series] schedule).
  • Only consider an additional viral vaccine dose (requires informed consent due to lack of evidence) when other mRNA authorized COVID-19 vaccines are either contraindicated or not available.
  • Separate the additional dose from final dose of the initial vaccine series by at least 28 days. Longer than 28 days may improve immune response.

Who should receive a booster dose of a COVID-19 vaccine?

A “booster dose” is a vaccine dose given to someone who responded appropriately to the initial vaccination series, to maintain immunity over time.131

In the U.S., booster doses (given ≥6 months after final dose of the two-dose series) with the Pfizer/BioNTech COVID-19 vaccine for people originally vaccinated with the Pfizer/BioNTech COVID-19 vaccine:

  • are recommended in the following people:55
    • 65 years of age and older.
    • long-term care residents.
    • 50 to 64 years of age with underlying medical conditions putting them at high risk for severe COVID-19 (e.g., diabetes, obesity).
  • may be given to people after considering benefits and risks:55
    • 18 to 49 years of age with underlying medical conditions (e.g., diabetes, obesity).
    • 18 to 64 years of age at increased risk for SARS-CoV-2 exposure (e.g., healthcare workers, teachers, prison inmates).

In the U.S., booster doses are not currently recommended for people originally vaccinated with the Moderna or Janssen/J&J COVID-19 vaccine.

In Canada, COVID-19 vaccine booster doses are not currently recommended. However, guidance on use of COVID-19 vaccine booster doses for certain patient populations is being considered (e.g., long-term care residents).42

Can COVID-19 vaccines be given with other vaccines?

No data are available about safety or efficacy of coadministration of a COVID-19 vaccine and other vaccines.49 Experience with other vaccines demonstrates that immunogenicity and adverse effects are generally similar when vaccines are given simultaneously as when they are given separately (e.g., separated by 14 days).49

  • COVID-19 vaccines may be given without regard to other vaccines (including the flu vaccine). There are no data regarding adverse effects with coadministration, especially with vaccines known to have increased side effects (e.g., adjuvanted vaccines).49,132
    • When considering coadministration, consider recommended vaccine schedules, the patient’s risk of vaccine-preventable disease (e.g., during an outbreak or occupational exposures), and the adverse effect profile of the vaccines.49

Should COVID-19 vaccines be avoided in patients taking anticoagulants or antiplatelets?

Taking an anticoagulant or antiplatelet is NOT a contraindication to receiving a COVID-19 vaccine
(e.g., aspirin, warfarin, enoxaparin, clopidogrel, apixaban).63-65

As with all other vaccines given IM, consider the following to minimize bleeding risk:63-65

  • Use a fine-gauge needle (e.g., 23-gauge, 25-gauge).
  • Apply firm pressure (without rubbing) to the injection site for at least two to three minutes after the injection.

Reassure patients that vaccination benefits outweigh the small risk of bruising. Serious effects are NOT expected. Advise patients to monitor for bleeding or bruising and to report unusual or excessive bleeding or bruising to their healthcare provider.65

Should someone who has COVID-19 or who was previously infected get vaccinated?

Previous COVID-19 infection (with or without symptoms) is NOT a contraindication to COVID-19 vaccination.31

It may be reasonable for people with recent COVID-19 infections to temporarily delay COVID-19 vaccination (especially when vaccine supply is limited), as the risk of reinfection is low in the months after initial infection, but infection risk may increase over time.31,49

Defer vaccination with a COVID-19 vaccine until patients have recovered from the acute COVID-19 illness and meet criteria to stop isolation (including patients who develop COVID-19 in between doses one and two of the vaccine).49

There is NOT clear guidance on whether or not to give COVID-19 vaccines to someone with an acute illness (other than COVID-19). In general, moderate to severe illness is considered a precaution against vaccination (as vaccination side effects can make it difficult to assess management of the acute illness), while vaccination during a mild illness (with or without fever) is not a precaution.43

Should someone who previously received monoclonal antibodies or convalescent plasma for COVID-19 get vaccinated?

There are no data about the use of COVID-19 vaccines in patients who received either monoclonal antibody therapy or convalescent plasma.49,69

To avoid any possibility of lessening a patient’s immune response to a COVID-19 vaccine, wait at least 90 days before vaccinating a patient who received either monoclonal antibody therapy (e.g., bamlanivimab, bamlanivimab/etesevimab [U.S. only], casirivimab/imdevimab, sotrovimab) or convalescent plasma to treat COVID-19.49 Waiting 90 days before vaccinating applies to patients before receiving any dose of a COVID-19 vaccine or who are in the middle of the vaccination series.49 In Canada, no specific timing recommendations can be made. Instead, involve an expert and make timing decisions on a case-by-case basis.69

Do COVID-19 vaccines contain aborted fetal cells?

Available COVID-19 vaccines do NOT contain fetal cells.60,83-86

Fetal cells lines are used in development, production, and/or confirmatory tests of available COVID-19 and some other vaccines (e.g., hepatitis A, rubella, shingles).83,85 For example, decades old fetal cell lines are used:60,83-86

  • to confirm that COVID-19 mRNA vaccines are taken up by cells and used as a blueprint to make a
    SARS-CoV-2 spike protein.
  • to grow the adenovirus used in the viral vector vaccines, but are filtered out during the vaccine production process.

What is the role for antibody testing to assess COVID-19 immunity?

Antibody testing is NOT recommended to check immune status after COVID-19 vaccination.49,117

  • Available antibody tests are not authorized to assess immune response to vaccines.49,117
  • Reassure patients that a negative antibody test after COVID-19 vaccination does not equate to a lack of protection. Not all authorized COVID-19 antibody tests detect the IgG and IgM antibodies to the “spike protein” used in COVID-19 vaccines.49 Antibody tests also do NOT tell us about B- or T-lymphocyte activity (e.g., B cells, T cells) which are also tools the immune system uses to mount an immune response.35 This means a fully vaccinated patient could have a negative antibody test with some tests.
  • Explain to patients that additional vaccine doses are NOT recommended based on a negative COVID-19 antibody test after vaccination.49
  • If patients get an antibody test in the middle of a COVID-19 vaccination series, encourage them to complete the series regardless of the antibody test result.49

Antibody testing is NOT recommended as part of the decision-making process about when patients with a prior COVID-19 infection should receive a COVID-19 vaccine.49 See the row “Should someone who has COVID-19 or who was previously infected get vaccinated?” for details on vaccination after a COVID-19 infection.

What should U.S. healthcare providers know about billing for COVID-19 vaccinations?

There will be no charge to patients for the COVID-19 vaccine. COVID-19 vaccines are currently purchased by the government. You will only be billing for the administration fee, not for the vaccine itself.2

To ensure pharmacy reimbursement for the administrative fee, it is recommended to enter the following:24

  • Quantity: use the volume to be injected for the specific vaccine being administered
  • Days’ supply: “1”
  • Professional services code: MA
  • Ingredient cost: $0.00 or $0.01 depending on the payer
  • Submission clarification code (SCC) (for vaccines requiring multiple doses):
    • “2” for the first dose (i.e., “other override” defined as, “used when authorized by the payer in business cases not currently addressed by other SCC values,” to indicate giving the first dose of a two-dose vaccine).
    • “6” for the second dose (i.e., “starter dose” defined as, “the pharmacist is indicating that the previous medication was a starter dose and now additional medication is needed to continue treatment,” to indicate giving the final dose of a two-dose vaccine).
    • 7 for the third/additional dose (i.e., indicates an additional dose is medically necessary, based on CDC recommendations)
    • 10  for the booster dose (some may temporarily require SCC 7 and 10 to be submitted together) 

Reimbursement rates for COVID-19 vaccine administration fees:74

  • First or subsequent dose of a multi-dose vaccine: $40 (a total of $80 for a two-dose series; a total of $120 for a three-dose series [e.g., third dose is given to a patient who is moderately or severely immunocompromised])
  • Dose of a single-dose vaccine: $40
  • Medicare also authorizes an additional $35.50 per dose for at home administration to help with access.  See for details and required documentation.39

COVID-19 vaccine and administrative CPT (current procedural technology) billing codes:2,24,39

  • Pfizer/BioNTech/Comirnaty: 91300 (vaccine); 0001A (administering first dose); 0002A (administering second dose); 003A (administering third dose); 004A (booster dose) 
  • Moderna: 91301 (vaccine); 0011A (administering first dose); 0012A (administering second dose); 0013A (administering third dose)
  • AstraZeneca: 91302 (vaccine); 0021A (administering first dose); 0022A (administering second dose)
  • Janssen/J&J: 91303 (vaccine); 0031A (single dose)

For additional medicare billing information(how to submit claims including institutional, professional, and for centralized billing), go to

For additional pharmacist-specific reimbursement information for COVID-19 vaccine administration (e.g., steps to take to ensure eligibility for reimbursement, becoming eligible to give vaccines under Medicare, how to handle uninsured patients), go to

  1. For more information about the V-SAFE monitoring system go to
  2. Operation Warp Speed is comprised of Department of Health and Human Services (HHS), including the Centers for Disease Control and Prevention (CDC), the National Institutes of Health (NIH), and the Biomedical Advanced Research and Development Authority (BARDA), and the Department of Defense (DoD).


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Cite this document as follows:  Clinical Resource, Communicating About COVID-19 Vaccination. Pharmacist’s Letter/Prescriber’s Letter.  April 2021[370401]

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