Covid-19 vaccine acceptance rate rising to over 73%


When queried in polls conducted earlier this year, only about half of American adults said they planned to get any vaccine against the new coronavirus.

But after a largely successful rollout this month of two safe and effective shots, many of those initial doubters now say they’ll line up to get their vaccine doses when their turn comes.

According to The New York Times, polls conducted by Gallup, the Kaiser Family Foundation and the Pew Research Center all show vaccine acceptance rates rising from about 50% this summer to more than 60% and, in one poll, 73%.

That last number approaches the threshold scientists have deemed necessary for herd immunity, where enough of a population is immune and the spread of the coronavirus begins to recede.

“As soon as it is my turn to get the vaccine, I will be there front and center! I am very excited and hopeful,” Joanne Barnes, 68, a retired elementary school teacher from Fairbanks, Alaska, told the Times.

Earlier this summer, Barnes had told the paper the opposite; that she would not get the shot. The game-changers for her, Barnes said, were “the Biden administration, returning to listening to science and the fantastic stats associated with the vaccines.”

With more than 19 million COVID-19 cases in the United States by Monday and more than 333,000 Americans now killed by the disease, more people than ever have now been personally affected by the new coronavirus. That harsh reality might also be driving some to reconsider getting the shot.

“More people have either been affected or infected by COVID,” Rupali Limaye, an expert on vaccine behavior at the Johns Hopkins Bloomberg School of Public Health in Baltimore, told the Times. “They know someone who had a severe case or died. They are fatigued and want to get back to their normal lives.”

Media campaigns, including on-camera moments with politicians and scientists – such as Vice President Mike Pence, President-Elect Joe Biden and Dr. Anthony Fauci—all rolling up their sleeves for the shots may have also helped boost acceptance.

Still, large pockets of skepticism and resistance to vaccination remain. According to the Times, mistrust of the vaccine is higher among Blacks than whites, among Republicans compared to Democrats, and among people living in rural areas versus those in cities.

Still, resistance is fading slowly among most groups, the Times said.

One Black American, Mike Brown, runs a barbershop in Hyattsville, Md. This summer he said he wouldn’t get any COVID-19 vaccine, but has since changed his mind.

“The news that it was 95% effective sold me,” Brown told the Times. “The side effects sound like what you get after a bad night of drinking and you hurt the next day. Well, I’ve had many of those and I can deal with that to get rid of the face masks.”

More vaccines coming

The U.S. supply of COVID-19 vaccines got a boost last week: Pfizer Inc. and the Trump administration were close to a deal on Tuesday that would get more of the company’s coronavirus vaccine to Americans in the coming year.

Such an agreement would help the United States manage a coming vaccine shortage that could leave up to 110 million Americans uncovered in the first half of 2021, the Times reported.

So far, only two pharmaceutical companies – Pfizer and Moderna – have won emergency approval for their COVID-19 vaccines. In the Pfizer negotiations, the government is asking for 100 million additional doses from April through June.

The company has indicated it could produce at least 70 million more doses if it can get more supplies and raw materials, the Times reported.

The deal calls for the government to invoke the Defense Production Act to give the company better access to roughly nine specialized products it needs to make the vaccine. One person familiar with the list said it included the lipids that encase the RNA material in both the Moderna and Pfizer vaccines, the Times reported.

Moderna and other companies that have worked more closely with Operation Warp Speed to develop their vaccines already receive favored treatment from suppliers, the Times reported.

That includes two companies – Sanofi and Novavax – that have yet to begin large clinical trials in the United States.

Pfizer has already contracted to deliver 100 million doses of its vaccine by the end of March. Moderna has the same agreement, and it has also pledged to sell the government 100 million more doses in the second quarter of the year, the Times reported.

Because the Pfizer and the Moderna vaccines both require two doses, that supply would cover only 150 million Americans out of the roughly 260 million who are eligible to be vaccinated, the newspaper said.

If Pfizer provides another 100 million doses, that would leave only about 60 million eligible Americans uncovered in the first half of the year, the Times reported. Other producers could also step in and cover the shortfall should their vaccines prove successful.

Experts say new COVID variant may already be in U.S.

But as the Pfizer and Moderna vaccines are shipped across the country, U.S. experts warned that the new, more infectious variant of the coronavirus recently discovered in Britain may already be circulating in the United States.

“We don’t know that for absolutely certain, but it is reasonable to assume that is going on,” Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said last week. “It very well might be here for all we know.”

Several infectious disease experts said last week that the variant may not have even originated in the United Kingdom, the Washington Post reported. Instead, it may have been identified there first because the British government has a strong monitoring system that has tracked tens of thousands of genomic sequences of virus samples.

The United States has lagged in sequencing and does not have nearly the same level of virus surveillance, the newspaper said.

“It may very well be here. It may have even started here. The sequencing in the U.S. is so sporadic,” Jeremy Luban, a virologist at the University of Massachusetts Medical School, told the Post.

According to Angela Rasmussen, a virologist at the Georgetown Center for Global Health Science and Security, in Washington, D.C., “It makes sense that it was detected first in the U.K. because they have probably the world’s best surveillance program. It would not shock me at all to find out that it also is circulating in the U.S.”

Even though this variant, officially known as B.1.1.7, is concerning and will require close monitoring, it is unlikely to undermine the United States’ mass coronavirus vaccination campaign, stressed William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health in Boston.

“The vaccine is a pretty thorough thing,” Hanage explained. “Whether or not the existing vaccines are less effective against B.1.1.7 is at the moment not known. I think there is good reason to think they will not be severely impacted.”

On Thursday, the U.S. Centers for Disease Control and Prevention announced a new rule that air passengers coming to the United States from the United Kingdom must provide documentation proving that they have tested negative for the new coronavirus within 72 hours of departure.

A global scourge

By Monday, the U.S. coronavirus case count passed 19.1 million while the death toll passed 333,000, according to a Times tally. On Monday, the top five states for coronavirus infections were: California with nearly 2.2 million cases; Texas with close to 1.7 million cases; Florida with almost 1.3 million cases; Illinois with over 939,000 cases; and New York with more than 928,000 cases.

Curbing the spread of the coronavirus in the rest of the world remains challenging.

In India, the coronavirus case count was over 10.2 million on Monday, a Johns Hopkins University tally showed. Brazil had over 7.4 million cases and over 191,000 deaths as of Monday, the Hopkins tally showed.

Worldwide, the number of reported infections passed 80.8 million on Monday, with nearly 1.8 million deaths recorded, according to the Hopkins tally.

The Advisory Committee on Immunization Practices (ACIP) has issued interim recommendations for the use of Pfizer-BioNTech and Moderna COVID-19 vaccines for the prevention of coronavirus disease 2019 (COVID-19) in the United States. Both vaccines are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes COVID-19.

These interim CDC clinical considerations are informed by data submitted to the Food and Drug Administration for Emergency Use Authorization (EUA) of the vaccines, other data sources, general best practice guidelines for immunization, and expert opinion. These considerations for mRNA vaccines only apply to the currently authorized vaccine products in the United States (i.e., Pfizer-BioNTech and Moderna COVID-19 vaccines). Considerations will be updated as additional information becomes available or if additional vaccine products are authorized.

In addition to the following considerations, the EUA conditions of use and storage, handling, and administration procedures described in the prescribing information should be referenced when using the Pfizer-BioNTechexternal icon and Modernaexternal icon COVID-19 vaccines.

Authorized age groups

Under the EUAs, the following age groups are authorized to receive vaccination:

  • Pfizer-BioNTech: ages ≥16 years
  • Moderna: ages ≥18 years

Children and adolescents outside of these authorized age groups should not receive COVID-19 vaccination at this time.


The mRNA COVID-19 vaccine series consist of two doses administered intramuscularly:

  • Pfizer-BioNTech (30 µg, 0.3 ml each): three weeks (21 days) apart
  • Moderna (100 µg, 0.5 ml): one month (28 days) apart

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.

Interchangeability with other COVID-19 vaccine products

Either of the currently authorized mRNA COVID-19 vaccines can be used when indicated; ACIP does not state a product preference. However, these mRNA COVID-19 vaccines are not interchangeable with each other or with other COVID-19 vaccine products. The safety and efficacy of a mixed-product series have not been evaluated.

Both doses of the series should be completed with the same product. However, if two doses of different mRNA COVID-19 vaccine products are inadvertently administered, no additional doses of either product are recommended at this time. Recommendations may be updated as further information becomes available or other vaccine types (e.g., viral vector, protein subunit vaccines) are authorized.

Coadministration with other vaccines

Given the lack of data on the safety and efficacy of mRNA COVID-19 vaccines administered simultaneously with other vaccines, the vaccine series should be administered alone, with a minimum interval of 14 days before or after administration with any other vaccines. If mRNA COVID-19 vaccines are inadvertently administered within 14 days of another vaccine, doses do not need to be repeated for either vaccine.

Booster doses

The need for and timing of booster doses for mRNA COVID-19 vaccines has not been established. No additional doses beyond the two-dose primary series are recommended at this time.

Vaccination of persons with a SARS-CoV-2 infection or exposure

Persons with a current or prior history of SARS-CoV-2 infection

Data from clinical trials indicate that mRNA COVID-19 vaccines are safe in persons with evidence of a prior SARS-CoV-2 infection. Vaccination should be offered to persons regardless of history of prior symptomatic or asymptomatic SARS-CoV-2 infection. Viral testing to assess for acute SARS-CoV-2 infection or serologic testing to assess for prior infection solely for the purposes of vaccine decision-making is not recommended.

Vaccination of persons with known current SARS-CoV-2 infection should be deferred until the person has recovered from the acute illness (if the person had symptoms) and criteria have been met for them to discontinue isolation. This recommendation applies to persons who develop SARS-CoV-2 infection before receiving any vaccine doses as well as those who develop SARS-CoV-2 infection after the first dose but before receipt of the second dose.

While there is otherwise no recommended minimum interval between infection and vaccination, current evidence suggests that reinfection is uncommon in the 90 days after initial infection. Thus, persons with documented acute SARS-CoV-2 infection in the preceding 90 days may delay vaccination until near the end of this period, if desired.

Persons who previously received passive antibody therapy for COVID-19

Currently, there are no data on the safety and efficacy of mRNA COVID-19 vaccines in persons who received monoclonal antibodies or convalescent plasma as part of COVID-19 treatment. Based on the estimated half-life of such therapies as well as evidence suggesting that reinfection is uncommon in the 90 days after initial infection, vaccination should be deferred for at least 90 days, as a precautionary measure until additional information becomes available, to avoid interference of the antibody treatment with vaccine-induced immune responses.

Persons with a known SARS-CoV-2 exposure

No data are currently available on the use of mRNA COVID-19 vaccines for post-exposure prophylaxis (i.e., vaccination to prevent the development of SARS-CoV-2 infection in a person with a recent exposure). However, current evidence suggests that this would be an ineffective strategy. The median incubation period of SARS-CoV-2 is 4 to 5 days, whereas the currently authorized mRNA COVID-19 vaccines consist of a 2-dose series and it takes 1 to 2 weeks following the second dose before a person is considered fully vaccinated.

Thus, persons in the community or outpatient setting who have had a known COVID-19 exposure should not seek vaccination until their quarantine period has ended to avoid potentially exposing healthcare personnel and other persons to SARS-CoV-2 during the vaccination visit.

For persons residing in congregate healthcare settings (e.g., long-term care facilities) where exposure and transmission of SARS-CoV-2 can occur repeatedly for long periods of time, residents with a known COVID-19 exposure may be vaccinated. In these settings, healthcare personnel are already in close contact with residents (e.g., entering patient rooms for evaluation and treatment) and should employ appropriate infection prevention and control procedures, so administering COVID-19 vaccine should not result in additional exposures.

Residents of other congregate settings (e.g., correctional and detention facilities, homeless shelters) with a known COVID-19 exposure may also be vaccinated, in order to avoid delays and missed opportunities for vaccination given the increased risk for outbreaks in these settings.

However, where feasible, precautions should be taken to limit mixing exposed individuals with other residents or staff (except those essential for the provision of vaccination services, who should employ appropriate infection and control procedures). Persons residing in congregate settings (healthcare and non-healthcare) with an exposure who are awaiting results of SARS-CoV-2 testing may be vaccinated if COVID-19 is not strongly suspected.

For example, when facility-wide testing is conducted because exposures have occurred in the facility, and this testing coincides with a period when a vaccination event is planned, those persons in whom COVID-19 is not strongly suspected may be vaccinated.

Although not contraindicated, vaccination may be deferred pending outcome of testing in persons strongly suspected of being infected with COVID-19. However, viral testing for acute SARS-CoV-2 infection solely for the purposes of vaccine decision-making is not recommended.

Vaccination of persons with underlying medical conditions

mRNA COVID-19 vaccines may be administered to persons with underlying medical conditions who have no contraindications to vaccination (see ‘contraindications’ section below). Clinical trials demonstrated similar safety and efficacy profiles in persons with some underlying medical conditions, including those that place them at increased risk for severe COVID-19, compared to persons without comorbidities. Information on groups with specific underlying medical conditions is included below.

Immunocompromised persons

Persons with HIV infection or other immunocompromising conditions, or who take immunosuppressive medications or therapies might be at increased risk for severe COVID-19. Data are not currently available to establish vaccine safety and efficacy in these groups. Persons with stable HIV infection were included in mRNA COVID-19 vaccine clinical trials, though data remain limited.

Immunocompromised individuals may still receive COVID-19 vaccination if they have no contraindications to vaccination. However, they should be counseled about the unknown vaccine safety profile and effectiveness in immunocompromised populations, as well as the potential for reduced immune responses and the need to continue to follow all current guidance to protect themselves against COVID-19 (see below).

Persons with autoimmune conditions

No data are currently available on the safety and efficacy of mRNA COVID-19 vaccines in persons with autoimmune conditions, though these persons were eligible for enrollment in clinical trials. No imbalances were observed in the occurrence of symptoms consistent with autoimmune conditions or inflammatory disorders in clinical trial participants who received an mRNA COVID-19 vaccine compared to placebo. Persons with autoimmune conditions who have no contraindications to vaccination may receive an mRNA COVID-19 vaccine.

Persons with a history of Guillain-Barré syndrome

To date, no cases of Guillain-Barré syndrome (GBS) have been reported following vaccination among participants in the Pfizer-BioNTech or Moderna COVID-19 vaccines clinical trials. With few exceptions, ACIP’s general best practice guidelines for immunization does not include history of GBS as a contraindication or precaution to vaccination. Persons with a history of GBS may receive an mRNA COVID-19 vaccine unless they have a contraindication to vaccination. Any occurrence of GBS following mRNA COVID-19 vaccination should be reported to the Vaccine Adverse Event Reporting System (VAERS).

Persons with a history of Bell’s palsy

Cases of Bell’s palsy were reported following vaccination in participants in both the Pfizer-BioNTech and Moderna COVID-19 vaccines clinical trials. However, the FDA does not consider these to be above the frequency expected in the general population and has not concluded that these cases were causally related to vaccination.

Post-authorization safety surveillance will be important to further assess any possible causal association. In the absence of such evidence, persons with a history of Bell’s palsy may receive an mRNA COVID-19 vaccine unless they have a contraindication to vaccination. Any occurrence of Bell’s palsy following mRNA COVID-19 vaccination should be reported to VAERS.

Vaccination of pregnant or lactating people

Pregnant people

Observational data demonstrate that while the absolute risk is low, pregnant people with COVID-19 have an increased risk of severe illness, including illness resulting in intensive care admission, mechanical ventilation, or death. Additionally, they might be at an increased risk of adverse pregnancy outcomes, such as preterm birth.

There are currently few data on the safety of COVID-19 vaccines, including mRNA vaccines, in pregnant people. Limited data are currently available from animal developmental and reproductive toxicity  studies. No safety concerns were demonstrated in rats that received Moderna COVID-19 vaccine prior to or during gestation in terms of female reproduction, fetal/embryonal development, or postnatal development. Studies in pregnant people are planned and the vaccine manufacturers are following outcomes in people in the clinical trials who became pregnant. mRNA vaccines are not live vaccines.

The mRNA in the vaccine is degraded quickly by normal cellular processes and does not enter the nucleus of the cell. Based on current knowledge, experts believe that mRNA vaccines are unlikely to pose a risk to the pregnant person or the fetus. However, the potential risks of mRNA vaccines to the pregnant person and the fetus are unknown because these vaccines have not been studied in pregnant people.

If pregnant people are part of a group that is recommended to receive a COVID-19 vaccine (e.g., healthcare personnel), they may choose to be vaccinated. A conversation between the patient and their clinical team may assist with decisions regarding the use of a mRNA COVID-19 vaccine, though a conversation with a healthcare provider is not required prior to vaccination.

When making a decision, pregnant people and their healthcare providers should consider the level of COVID-19 community transmission, the patient’s personal risk of contracting COVID-19, the risks of COVID-19 to the patient and potential risks to the fetus, the efficacy of the vaccine, the side effects of the vaccine, and the lack of data about the vaccine during pregnancy.

Side effects can occur with COVID-19 vaccine use in pregnant people, similar to those expected among non-pregnant people. Pregnant people who experience fever following vaccination may be counseled to take acetaminophen as fever has been associated with adverse pregnancy outcomes. Acetaminophen may be offered as an option for pregnant people experiencing other post-vaccination symptoms as well.

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.

Lactating people

There are no data on the safety of COVID-19 vaccines in lactating people or the effects of mRNA COVID-19 vaccines on the breastfed infant or milk production/excretion. mRNA vaccines are not thought to be a risk to the breastfeeding infant. A lactating person who is part of a group recommended to receive a COVID-19 vaccine (e.g., healthcare personnel) may choose to be vaccinated.

Vaccination of children and adolescents

Adolescents aged 16–17 years are included among persons eligible to receive the Pfizer-BioNTech COVID-19 vaccine under the EUA. While vaccine safety and efficacy data in this age group are limited, there are no biologically plausible reasons for safety and efficacy profiles to be different than those observed in persons 18 years of age and older.

Adolescents aged 16–17 years who are part of a group recommended to receive a COVID-19 vaccine may be vaccinated with the Pfizer-BioNTech COVID-19 vaccine, with appropriate assent. Children and adolescents younger than 16 years of age are not authorized to receive the Pfizer-BioNTech COVID-19 vaccine at this time.

Children and adolescents younger than 18 years of age are not authorized to receive the Moderna COVID-19 vaccine at this time.

Patient counseling

Vaccine efficacy

Preliminary data suggest high vaccine efficacy in preventing COVID-19 following receipt of two doses of mRNA COVID-19 vaccine (Pfizer-BioNTech: 95.0% [95% CI: 90.3%, 97.6%]; Moderna: 94.1% [95% CI: 89.3%, 96.8%]). Limited data are currently available regarding the efficacy of a single dose. Patients should be counseled on the importance of completing the two-dose series (of the same vaccine product) to optimize protection.


Before vaccination, providers should counsel mRNA COVID-19 vaccine recipients about expected local (e.g., pain, swelling, erythema at the injection site, localized axillary lymphadenopathy on the same side as the vaccinated arm) and systemic (e.g., fever, fatigue, headache, chills, myalgia, arthralgia) post-vaccination symptoms. Depending on vaccine product (Pfizer vs. Moderna), age group, and vaccine dose, approximately 80–89% of vaccinated persons develop at least one local symptom and 55–83% develop at least one systemic symptom following vaccination.

Most systemic post-vaccination symptoms are mild to moderate in severity, occur within the first three days of vaccination, and resolve within 1–3 days of onset. These symptoms are more frequent and severe following the second dose and among younger persons compared to older persons (i.e., >55 or ≥65 years [for Pfizer-BioNTech or Moderna vaccines, respectively]).

Unless persons develop a contraindication to vaccination (see below), they should be encouraged to complete the series even if they develop local or systemic symptoms following the first dose to optimize protection against COVID-19.

Hypersensitivity-related adverse events were observed in 0.63% of Pfizer-BioNTech and 1.5% of Moderna COVID-19 vaccine clinical trial participants who received the vaccine, compared to 0.51% and 1.1%, respectively, in the placebo groups. Anaphylaxis following vaccination was not observed in the Pfizer-BioNTech or Moderna COVID-19 vaccine clinical trials. However, anaphylactic reactions have been reported following receipt of the Pfizer-BioNTech COVID-19 vaccine during vaccination outside of clinical trials.

Antipyretic or analgesic medications (e.g., acetaminophen, non-steroidal anti-inflammatory drugs) may be taken for the treatment of post-vaccination local or systemic symptoms, if medically appropriate. However, routine prophylactic administration of these medications for the purpose of preventing post-vaccination symptoms is not currently recommended, as information on the impact of such use on mRNA COVID-19 vaccine-induced antibody responses is not available at this time.

Infection prevention and control considerations are available for healthcare personnel and long-term care facility residents (e.g., populations included in phase 1a of vaccine allocation) with systemic signs and symptoms following COVID-19 vaccination. Considerations may be updated as additional information becomes available or additional groups are prioritized for vaccine allocation.

Public health recommendations for vaccinated persons

Given the currently limited information on how much the mRNA COVID-19 vaccines may reduce transmission in the general population and how long protection lasts, vaccinated persons should continue to follow all current guidance to protect themselves and others.

This includes wearing a mask, staying at least 6 feet away from others, avoiding crowds, washing hands often, following CDC travel guidance, following quarantine guidance after an exposure to someone with COVID-19, and following any applicable workplace or school guidance, including guidance related to personal protective equipment use or SARS-CoV-2 testing.

Contraindications and precautions


Severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine is a contraindication to vaccination for both the Pfizer-BioNTechexternal icon and Modernaexternal icon COVID-19 vaccines. See Appendix A for further information on vaccine ingredients.


Anaphylactic reactions in persons who received Pfizer-BioNTech COVID-19 vaccine outside of clinical trials have been reported. While these reports are further investigated, CDC considers a history of severe allergic reaction (e.g., anaphylaxis) to any other vaccine or injectable therapy (e.g., intramuscular, intravenous, or subcutaneous) as a precaution but not a contraindication to vaccination for both the Pfizer-BioNTech and Moderna COVID-19 vaccines (as these vaccines contain ingredients in common). These persons may still receive mRNA COVID-19 vaccination, but they should be counseled about the unknown risks of developing a severe allergic reaction and balance these risks against the benefits of vaccination.

A history of mild allergic reaction to a vaccine or injectable therapy, such as localized urticaria alone without signs or symptoms of anaphylaxis, is not a contraindication or precaution to vaccination with either mRNA COVID-19 vaccine. In addition, allergic reactions (including severe allergic reactions) not related to vaccines or injectable therapies (e.g., food, pet, venom, or environmental allergies; allergies to oral medications [including the oral equivalents of injectable medications]) are not a contraindication or precaution to vaccination with either mRNA COVID-19 vaccine. The vial stoppers of these mRNA vaccines are not made with natural rubber latex, and there is no contraindication or precaution to vaccination for persons with a latex allergy.

Risk assessment for mRNA COVID-19 vaccination

When assessing a person’s history of allergic reaction to a vaccine or injectable therapy, it can sometimes be challenging to determine whether the reaction was truly severe. The following considerations can be used to help the provider conduct a risk assessment for mRNA COVID-19 vaccination:

  • Type of reaction and symptoms (e.g., whether symptoms were generalized and consistent with anaphylaxis)
  • For a reaction to a medication, whether the medication was administered by injection or another route
  • Whether the reaction required use of epinephrine (EpiPen®, etc.) or resulted in advanced medical care, (e.g., emergency room visit, hospitalization)
  • How long ago the reaction occurred and whether the same vaccine or medication was subsequently administered without symptoms
  • Whether the patient has been evaluated by an allergist-immunologist and the diagnosis has been confirmed

Persons who are determined to have had a severe allergic reaction (e.g., anaphylaxis) to an mRNA COVID-19 vaccine should not receive a second dose. For those determined to have had a severe allergic reaction to another vaccine or injectable medication, considerations for the administration of an mRNA COVID-19 vaccine might include:

  • Risk of exposure to SARS-CoV-2 (e.g., because of residence in a congregate setting such as a long-term care facility, occupation)
  • Risk of severe disease or death due to COVID-19 (e.g., because of age, underlying medical conditions)
  • The unknown risk of anaphylaxis (including fatal anaphylaxis) following mRNA COVID-19 vaccination in a person with a history of anaphylaxis to other vaccines or injectable therapies
  • Ability of the patient to be vaccinated in a setting where advanced medical care is immediately available for anaphylaxis
  • Risk of adverse events after anaphylaxis treatment with epinephrine (older adults with hypertension and atherosclerotic heart disease may be at increased risk for cardiac adverse events following anaphylaxis treatment with epinephrine)
  • Whether the patient has previously been infected with SARS-CoV-2 and, if so, how long ago
    • Note: Vaccination is recommended for persons with a history of COVID-19; however, because reinfection is uncommon in the 90 days following infection, persons with a history of anaphylaxis to another vaccine or injectable therapy and recent COVID-19 may choose to defer vaccination until further information is known about the risk of anaphylaxis following vaccination.

Management of allergic reactions

Appropriate medical treatment used to manage immediate allergic reactions must be immediately available in the event that an acute anaphylactic reaction occurs following administration of an mRNA COVID-19 vaccine. Vaccine providers should observe patients with a history of anaphylaxis (due to any cause) for 30 minutes after vaccination. All other persons should be observed for 15 minutes after vaccination to monitor for the occurrence of immediate adverse reactions. Further information on preparing for the potential management of anaphylaxis at COVID-19 vaccination sites has been published.

See Appendix B for additional information on the triage and management of persons presenting for mRNA COVID-19 vaccination.

Reporting of vaccine adverse events

Adverse events that occur in a recipient following mRNA COVID-19 vaccination should be reported to VAERS. Vaccination providers are required by the Food and Drug Administration to report the following that occur after mRNA COVID-19 vaccination under Emergency Use Authorization:

  • Vaccine administration errors
  • Serious adverse events
  • Cases of Multisystem Inflammatory Syndrome
  • Cases of COVID-19 that result in hospitalization or death

Reporting is encouraged for any other clinically significant adverse event even if it is uncertain whether the vaccine caused the event. Information on how to submit a report to VAERS is available at https://vaers.hhs.govexternal icon or by calling 1-800-822-7967.

In addition, CDC has developed a new, voluntary smartphone-based tool, v-safe. This tool uses text messaging and web surveys to provide near real-time health check-ins after patients receive COVID-19 vaccination. Reports to v-safe indicating a medically significant health impact, including pregnancy, are followed up by the CDC/v-safe call center to collect additional information to complete a VAERS report, if appropriate.

Interpretation of SARS-CoV-2 test results in vaccinated persons

Prior receipt of an mRNA COVID-19 vaccine will not affect the results of SARS-CoV-2 viral tests (nucleic acid amplification or antigen tests). Currently available antibody tests for SARS-CoV-2 assess IgM and/or IgG to one of two viral proteins: spike or nucleocapsid. Because both the Pfizer-BioNTech and Moderna COVID-19 vaccines contain mRNA that encodes the spike protein, a positive test for spike protein IgM/IgG could indicate either prior infection or vaccination.

To evaluate for evidence of prior infection in an individual with a history of mRNA COVID-19 vaccination, a testexternal icon specifically evaluating IgM/IgG to the nucleocapsid protein should be used. Antibody testing is not currently recommended to assess for immunity to COVID-19 following mRNA COVID-19 vaccination or to assess the need for vaccination in an unvaccinated person.Top of Page

Appendix A: Ingredients included in Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines

For both Pfizer-BioNTech and Moderna COVID-19 vaccines, severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine is a contraindication to vaccination. The following is a list of ingredients for the Pfizer-BioNTechexternal icon and Modernaexternal icon COVID-19 vaccines, as reported in the prescribing information for each vaccine.

DescriptionPfizer-BioNTech COVID-19 vaccineModerna COVID-19 vaccine
mRNANucleoside-modified mRNA encoding the viral spike (S) glycoprotein of SARS-CoV-2Nucleoside-modified mRNA encoding the viral spike (S) glycoprotein of SARS-CoV-2
Lipids2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamidePolyethylene glycol (PEG) 2000 dimyristoyl glycerol (DMG)
(4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate)SM-102 (Proprietary to Moderna)
Salts, sugars, buffersPotassium chlorideTromethamine
Monobasic potassium phosphateTromethamine hydrochloride
Sodium chlorideAcetic acid
Dibasic sodium phosphate dihydrateSodium acetate

Note: Both the Pfizer-BioNTech and Moderna COVID-19 vaccines contain polyethylene glycol (PEG). PEG is a primary ingredient in osmotic laxatives and oral bowel preparations for colonoscopy procedures, an inactive ingredient or excipient in additional medications (including some injectable contraceptives and steroids), and is used in a process called pegylation to improve the therapeutic activity of some medications (including certain chemotherapeutics).1,2 Neither of the Pfizer-BioNTech or Moderna COVID-19 vaccines contains preservatives.

  1. Stone Jr, Cosby A., et al. “Immediate hypersensitivity to polyethylene glycols and polysorbates: more common than we have recognized.” The Journal of Allergy and Clinical Immunology: In Practice5 (2019): 1533-1540. iconexternal icon
  2. DailyMed database. icon

Appendix B: Triage of persons presenting for mRNA COVID-19 vaccination

– Immunocompromising conditions
– Pregnancy
– Lactation
– Additional information provided*
– 15 minute observation period
– Moderate/severe acute illness

– Risk assessment
– Potential deferral of vaccination
– 15 minute observation period if vaccinated
– None
– N/A
– History of food, pet, insect, venom, environmental, latex, or other allergies not related to vaccines or injectable therapies
– History of allergy to oral medications (including the oral equivalent of an injectable medication)
– Non-serious allergy to vaccines or other injectables (e.g., no anaphylaxis)
– Family history of anaphylaxis
– Any other history of anaphylaxis that is not related to a vaccine or injectable therapy

– 30 minute observation period: Persons with a history of severe allergic reaction (e.g., anaphylaxis) due to any cause
– 15 minute observation period: Persons with allergic reaction, but not anaphylaxis
– History of severe allergic reaction (e.g., anaphylaxis) to another vaccine (not including mRNA COVID-19 vaccines)
– History of severe allergic reaction (e.g., anaphylaxis) to an injectable therapy
– Risk assessment
– Potential deferral of vaccination
– 30 minute observation period if vaccinated
– History of severe allergic reaction (e.g., anaphylaxis) to any component of an mRNA COVID-19 vaccine
– Do not vaccinate

* See Special Populations section for information on patient counseling in these groups

† Refers only to mRNA COVID-19 vaccines currently authorized in the United States (i.e., Pfizer-BioNTech, Moderna COVID-19 vaccines)

More information: The U.S. Centers for Disease Control and Prevention has more on the new coronavirus.


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