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COVID-19 Vaccines: Questions and Answers

COVID 19 vaccineIn a remarkable feat of science, multiple vaccine candidates against coronavirus disease 2019 (COVID-19, otherwise known as the SARS-CoV-2 virus) have been developed, tested and released under what is known as an Emergency Use Authorization (EUA) by the Food and Drug Administration (FDA). This incredibly important development in the fight against COVID-19 began less than 10 months since the World Health Organization (WHO) declared COVID-19 a worldwide pandemic on March 11, 2020. Indeed, several of these have now obtained full approval by the FDA – a vaccine known as Comirnaty for use in people 12 years and older, and Spikevax for those 18 years and older.
 
An EUA refers to the FDA allowing unapproved medical products or unapproved uses of approved medical products to be used in an emergency public health situation when there are no adequate, approved, and available alternatives. Four vaccines have been authorized to date. These include mRNA (messenger RNA, a nucleic acid that contains genetic material)-based vaccines. The first is by Pfizer-BioNTech (Comirnaty), which is now fully indicated in patients 12 years and older, given in two injections spaced 3 weeks apart. An EUA is present for a three-dose primary series for individuals 6 months through 4 years of age and a two-dose primary series for individuals from 5 through 11 years of age. The second mRNA vaccine is by Moderna (Spikevax), which obtained approval on December 18, 2020, for patients 18 years and older, given in two injections spaced 4 weeks apart. This also received full approval earlier in 2022. Emergency authorization has now been granted for children aged 6 months and older as a two-dose primary series. Immunocompromised individuals (including children) may require a third vaccine in their series of the mRNA vaccines.

A third vaccine by Johnson & Johnson is a non-replicating adenovirus vector vaccine containing viral DNA and is given as only one-dose to individuals 18 years and older.

A fourth vaccine called Novavax is a traditional protein subunit vaccine that is given as two doses, 3 weeks apart, in individuals 18 years of age and older.

It is recommended that the Johnson & Johnson vaccine be given only when the mRNA and the Novavax vaccines cannot be given because of the risk for side effects. Also, neither the Johnson & Johnson vaccine nor the Novavax vaccine should be given as boosters.

Regardless of the initial vaccine given, a booster dose of the mRNA vaccines is also recommended in those 12 years and older. This includes an additional injection 5 months after the original series of Pfizer or Moderna, or 2 months after the Johnson & Johnson vaccination. A second booster dose is now available for those over 50 and certain immunocompromised individuals. As well, updated boosters have recently been approved by the FDA for greater protection against the Omicron variants known as BA.4 and BA.5 – these are given 2 months after primary or booster doses of the original vaccines. The Moderna Bivalent booster is for those 18 years and older, and the Pfizer Bivalent booster is indicated in those 12 years and older.

Both mRNA vaccines make the body form an immune response in a similar fashion. A small portion of viral protein is encoded on the mRNA and delivered to the body with instructions in how to make proteins found in the virus. Cells make this protein and display it on their surface. The immune system then makes antibodies to this protein because it is recognized as foreign. That way, if the immune system encounters the COVID-19 virus in the future, the pre-made antibodies and other immune pathways will defend the body from infection. The DNA-based vaccine uses a viral vector to get the genetic material into the cell. Again, the body starts to recognize foreign protein that has been produced and presented on the cell surface and forms an immune response. Protein subunit vaccines use the traditional method of introducing foreign protein directly into the body, allowing for an immune response.

Understandably, many questions come to light surrounding the release of these vaccines.

Under an EUA, are these vaccines still considered safe?
Even though the FDA has initially authorized release of these vaccines through an EUA, they are still considered safe. The same rigorous Phase 3 testing is necessary to show that they meet standards of both efficacy and safety in patients, as is true with other approved vaccines. Full approval of both Comirnaty and Spikevax attests to this process.

Studies of all vaccines have shown an efficacy in adults from 66% in the single-dose vaccine to greater than 90% of the multiple-dose vaccines in a diverse population of more than 110,000 participants. These trials were placebo controlled, meaning that some patients received the active vaccine, while others received the placebo. It was clearly shown that the patients receiving the active vaccine were much less likely to become infected by COVID-19. Of the small number of patients that did become infected, they were far less likely to get severe infection or to be hospitalized. Booster doses appear to provide even greater protection against COVID-19, including the recent Omicron variant, as protective antibody levels appear to decrease over time.

Side effects of the vaccines included pain and redness at the site of the injection in the arm, and sometimes systemic symptoms like fever, chills, fatigue or a headache that may last a few days.

Do the vaccines contain live virus?
The vaccines do not contain any live virus, so you cannot get COVID-19 from the vaccine. And even though the vaccines use the concept of either mRNA or DNA so that our cells make the ‘spike-protein’, this genetic material does not enter the nucleus of the cells and does not incorporate itself into our own genes. After making the protein, the new genetic material is destroyed.

I know or think I may have already had COVID-19. Should I still receive the vaccine?
People who have already had COVID-19 or suspect they may have been infected should still get the vaccine. It is not known how long the immunity of natural infection lasts, so the vaccine should help in further reducing the risk of reinfection. It is recommended that people are asymptomatic and finish their isolation before receiving the vaccine. If they receive monoclonal antibodies to treat their COVID-19 infection, they should wait 90 days before being vaccinated.

I have an immunodeficiency. Can I still receive the vaccine?
The current mRNA vaccines do not contain live virus, so there is no risk of infection. If you have a primary or secondary immunodeficiency, or are taking medications to suppress the immune system, they simply may not work as well. The single-dose DNA vaccine is delivered in the form of a non-replicating adenovirus vector. Again, there is no live COVID-19 virus in this vaccine.

You should speak to your treating physician about receiving any of these vaccines to see which of the vaccines may be most appropriate. A third dose has been recommended for certain immunocompromised individuals (this is in addition to the booster).

I have allergies. Can I still receive the vaccine?
There have been several cases in the media of patients having allergic reactions to the Pfizer-BioNTech and the Moderna vaccines. Severe allergic reactions to any vaccine are possible, but are very rare.

It is not yet clear what caused the allergic reaction in these cases. One additional ingredient to this vaccine is a compound known as polyethylene glycol. This material has many uses in the medical industry. Most commonly it is used as a laxative. Patient who are known to be allergic to polyethylene glycol should NOT receive the vaccine.

Patient with allergies to food, latex, insect stings or inhalant allergens are not thought to be at increased risk of an allergy to this vaccine.

The Centers for Disease Control and Prevention (CDC) already has several recommendations regarding the administration and management of allergic reactions to the Pfizer-BioNTech vaccine. These include:
•    Those with a history of severe allergic reaction (e.g., anaphylaxis) to an injectable medication or other vaccine should use caution when receiving the vaccine and be observed during a 30-minute observation period.
•    Those with a history of severe allergic reaction to any component of the Pfizer-BioNTech COVID-19 vaccine (including polyethylene glycol) should not be vaccinated with the Pfizer-BioNTech COVID-19 vaccine.
•    In all cases, the vaccine should be administered in a healthcare setting where severe allergies (e.g., anaphylaxis) can be treated. Epinephrine is the first-line treatment for anaphylaxis and should be readily available.

If you have any concerns regarding your own risk for an allergic reaction to the COVID-19 vaccines, speak with your allergist.

Additional Questions
There are still many questions related to vaccines against COVID-19. It’s not yet clear how long immunity from these vaccines will last against COVID-19, and it’s also not clear at the present time if the vaccines prevent transmission of the disease.

Evidence of vaccine safety in pregnant or lactating women has been growing. The CDC now recommends vaccination for all people 12 years and older, including people who are pregnant, breastfeeding, trying to get pregnant now or might become pregnant in the future. MothertoBaby, a research partner of the AAAAI, has more information on the vaccine in pregnant and lactating women at mothertobaby.org.

There are other vaccine candidates on the horizon, and with very different mechanisms of action compared to the three vaccines that are currently authorized. Each will have their own recommendations and safety data. Yet hopefully as more of the population gets vaccinated, starting with our front-line workers and long-term care residents, the number of infections in the population will begin to slow and many lives will be saved.

COVID-19 VACCINES: QUICK SUMMARY

Four vaccines have been released to stop people from getting sick with the COVID-19 virus. These include a vaccine by Pfizer-BioNTech (called Comirnaty) for patients 6 months and older, and a vaccine by Moderna (called Spikevax) for patients 6 months and older. Both vaccines are given as a two or three-dose series depending on age. A third vaccine, by Johnson & Johnson, has recently been released. This is given as a single dose in people 18 years or older. A fourth vaccine, Novavax, is given as two doses, 3 weeks apart, in people 18 years of age and older. Booster vaccination (after an initial series, and with the mRNA vaccines) is now recommended for everyone 12 years and older and a second booster is recommended for those over 50 or those with certain immunodeficiencies.

Are these vaccines safe?
All of these vaccines are safe and work very well. It was shown that the patients who had the vaccines were much less likely to catch the COVID-19 virus. Of the small number of patients that did get the virus, they were far less likely to get severely ill.

Side effects of the vaccines included pain and redness at the site of the injection in the arm, and sometimes symptoms like fever, chills, tiredness or a headache that may last a few days.

Do the vaccines contain live virus?
The vaccines do not contain any live virus, so you cannot get COVID-19 from the vaccine. They also don’t make any changes to our own genes.
 
I know or think I may have already had COVID-19. Should I still receive the vaccine?
People who know or think that they have had COVID-19 before should still get the vaccine. These vaccines should help reduce the risk from getting sick again. If you are still sick from COVID-19, you should wait until you feel better before getting the vaccine.

I have allergies. Can I still receive the vaccine?
There have been some cases in the media of patients having allergic reactions to these vaccines. Severe allergic reactions to any vaccine are possible, but are very rare. Patients who are known to be allergic to a product called polyethylene glycol or any other components of the vaccines should NOT receive them.

Patient with allergies to food, latex, insect stings or environmental allergens are not at a higher risk of allergic reaction.

If you have any concerns about your own risk for an allergic reaction to the COVID-19 vaccines, or you have a disease such as an immune deficiency, speak with your allergist or your treating physician to see if you can safely receive them.

Reviewed: 9/8/22