Originally posted January 18, 2021; most recently updated September 24, 2021
Q: Are there any contraindications to getting a COVID-19 vaccine?
A: According to the CDC, people who have had an immediate allergic reaction, even if it was not severe, to a vaccine or injectable therapy (i.e., intramuscular, intravenous, or subcutaneous vaccines or therapies [excluding subcutaneous immunotherapy for allergies , i.e. “allergy shots”] not related to a component of mRNA COVID-19 vaccines or polysorbate), should consult their physicians to determine if they should get a COVID-19 vaccine. The CDC states this is a precaution and not a contraindication.
According to the CDC, COVID-19 vaccines and other vaccines may now be administered without regard to timing. This includes simultaneous administration of COVID-19 vaccines and other vaccines on the same day, as well as coadministration within 14 days. Following reports of a small number of patients experiencing anaphylaxis after getting an mRNA COVID-19 vaccine, the CDC issued guidance related to the mRNA COVID-19 vaccines and severe allergic reactions. ACAAI also published guidance on the risk of allergic reactions to mRNA COVID-19 vaccines.
Patients who have an immediate (<4 hours) or severe allergic reaction to the first dose of the mRNA COVID-19 vaccine should not receive the second dose.
The mRNA COVID-19 vaccines should not be administered to individuals with a known history of a severe allergic reaction to any component of the vaccine. Although the specific vaccine component causing anaphylaxis has not been identified, polyethylene glycol (PEG) is one of the ingredients in these vaccine products and has been known to cause anaphylaxis. The J&J vaccine should not be administered to individuals with an immediate allergic reaction to any ingredient in the vaccine (such as polysorbate).
Patients who have had COVID-19 and received monoclonal antibodies or convalescent serum to treat COVID-19 should wait 90 days before getting the vaccine.
Q: What if an individual has an immediate allergic reaction to their first mRNA shot? Can the J&J vaccine be given as a “booster?”
A: The CDC recommends individuals discuss this with their doctor. After taking a detailed history, allergists will have a risk/benefit discussion with their patient and if the patient has no contraindications to the J&J vaccine, may recommend their patient use J&J as a booster vaccination; however, there is no current data on the efficacy or safety of using the J&J vaccine this way.
Q: How many doses of the COVID-19 vaccine will be needed?
A: The Pfizer and Moderna COVID-19 vaccines require two doses. The J&J vaccine requires one dose.
Q: What happens when someone is late getting their second mRNA dose?
A: The Pfizer COVID-19 vaccine dosing schedule recommends the second dose be given 21 days after the first dose (with a 4-day grace period). The Moderna vaccine schedule recommends the second dose be given 28 days after the first shot. If it is not feasible to adhere to the recommended interval, the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines may be scheduled for administration up to 6 weeks (42 days) after the first dose.
Q: What happens when someone fails to get the second dose of the vaccine?
A: The efficacy of a single dose of the approved vaccines is much lower than if a patient receives the recommended 2 injections. Protection offered by a single dose of vaccine has been estimated to be at 50%, and the second dose increases this to more than 90%.
Q: Do both doses of the Pfizer and Moderna vaccines need to be with the same vaccine product?
A: Yes, if at all possible. According to the CDC, every effort should be made to determine which vaccine product was received as the first dose, in order to ensure completion of the vaccine series with the same product. In exceptional situations in which the first-dose vaccine product cannot be determined or is no longer available, any available mRNA COVID-19 vaccine may be administered at a minimum interval of 28 days between doses to complete the mRNA COVID-19 vaccination series. If two doses of different mRNA COVID-19 vaccine products are administered, no additional doses of either product are recommended.
Q: If someone already had COVID-19 and recovered, do they still need to get a COVID-19 vaccine?
A: Yes, according to the CDC, COVID-19 vaccination should be offered regardless of whether an individual has already had COVID-19 infection. An antibody test is not required prior to vaccination. Current evidence suggests that reinfection with the virus that causes COVID-19 is uncommon in the 90 days after the initial infection. However, experts don’t know how long this protection lasts, and the risk of illness and death from COVID-19 far outweighs any benefits of natural immunity. It also appears that vaccination offers better protection and reduced transmission of the COVID-19 than the immunity that comes from having COVID-19 (natural immunity). However, anyone currently infected with COVID-19 should wait to get vaccinated until after their illness has resolved and after they have met the criteria to discontinue isolation.
If you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine.
Q: Will my nasal PCR swab or antigen testing be positive after I get the COVID-19 vaccine?
A: The COVID-19 vaccines will not influence the results of PCR or antigen testing for the disease. The vaccines generate antibodies to SARS-CoV-2, which are directed at the spike protein. Some available serologic assays test for this antibody; others do not. The manufacturers of the individual antibody tests should be able to provide this information, and it is often listed in the package insert.
Q: What if someone gets a COVID-19 vaccine and subsequently gets COVID-19 before receiving the second COVID-19 vaccine? Should they get the second dose?
A: When to get the second dose of COVID-19 vaccine is multifactorial and depends upon the medications used to treat the COVID-19 infection. This decision should be made using a shared decision-making model with a provider.
According to the CDC, prior receipt of an mRNA COVID vaccine should not affect treatment decisions including the use of monoclonal antibody therapy, convalescent plasma, antiviral treatment or corticosteroid administration.
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 potential interference of the antibody therapy with vaccine-induced immune responses. This recommendation applies to persons who receive passive antibody therapy before receiving any vaccine doses. It also applies to those who receive passive antibody therapy after the first dose but before the second dose, in which case the second dose should be deferred for at least 90 days following receipt of the antibody therapy..
If no monoclonal antibody therapy is administered, then a booster dose can be administered after recovery from COVID-19 and the isolation period has ended.
Q: Is a history of receiving injected dermal fillers a contraindication to getting the mRNA COVID-19 vaccine?
A: Having had dermal filler injections is not a contraindication for mRNA vaccine administration. People who have received dermal fillers may develop swelling at or near the site of the filler injection following administration of an mRNA COVID-19 vaccine. The symptom is temporary and treatable and has been seen with other vaccines.
Q: Can someone get a COVID-19 vaccine if they have an underlying medical condition such as HIV or another immunocompromising condition, autoimmune condition, a history of Guillain-Barre syndrome or Bell’s palsy?
A: COVID-19 vaccine may be administered to persons with underlying medical conditions who have no contraindications to vaccination. In fact, 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. The risks and benefits should be discussed with the individual patient depending on their underlying medical condition.
Patients with a history of Guillain-Barre syndrome within six weeks of vaccine should avoid the same vaccine. GBS not associated with a vaccine is not a contraindication nor precaution for receiving the COVID-19 vaccine. Bell’s palsy is not a contraindication to receiving the vaccine.
Q: What if someone received the vaccination during cancer treatment and the treatments are now over? Should they get vaccinated again?
A: Revaccination is not currently recommended after immune competence is regained in people who received COVID-19 vaccines during chemotherapy or treatment with other immunosuppressive drugs.
Q: Does immunity after getting COVID-19 last longer than protection from COVID-19 vaccines?
A: The protection someone gains from having an infection (called natural immunity) varies depending on the disease, and it varies from person to person. Since this virus is new, we don’t know how long natural immunity might last but is variable among individuals. Some evidence suggests natural immunity can last at least 6 to 8 months and, perhaps, up to a year. There have been cases where individuals have been shown to be infected twice, but most often the second illness was mild or without any symptoms. This is what we would expect with an immune response that protects against disease but not infection.
Vaccination after recovery from a COVID infection provides up to 50 times more immunity than natural infection, so getting the vaccine is important, even if one has had the infection.
We do not know how long protection will last following vaccination in uninfected people, but early evidence suggests it lasts at least six months in most people. It may not have the same duration of benefit in certain population, such as the elderly or others with impaired immunity.
Booster shots are recommended for immunocompromised at this time along with certain other populations who received the Pfizer vaccines. Approval for booster shots for Moderna and J&J vaccines is expected in the future once additional data is available. It continues to be critically important to monitor long-term protection in various groups of people.
Q: How should people protect themselves from getting COVID-19 if they have not received the vaccine?
A: Everyone should cover their mouth and nose with a mask when around others (except those under 2 years of age or with medical conditions that prevent wearing a mask); avoid close contact with people who are sick; stay six feet away from others; avoid crowds; and wash their hands often. Get more information about these and other steps you can take to protect yourself and others from COVID-19.
Q: How much will the COVID-19 vaccine cost?
A: There is no cost. The shots are free to everyone, even if you don’t have health insurance. The federal government is covering the cost.