Vaccine Q & A

Dr. David Hopper '63, one of three medical professionals on the University's COVID Response Team, takes time to answer questions on the various vaccines.

Vaccine Graphic

How do the specific vaccines work?

As with all vaccines, the injected solution contains information that directs your immune system to make antibodies against a critical part of a virus or bacteria. Its Achilles’ Heel. In the case of SARS-CoV2 it is its spike protein. The virus uses this protein to attach to your cell before entering it, which is critical to its life cycle. In addition, the vaccines also instruct your body to make memory cells (T-cells) that remember this foreign substance. Thus, insuring that when you see this same protein in the future, your immune system promptly takes the appropriate steps to protect you against the pathogen.

The difference in vaccines is how these instructions are conveyed to your immune system.The following is a review of the currently approved Emergency Use Authorization (EUA) vaccines & how they direct your immune system.

There are several types of Covid-19 vaccines:

1) mRNA Vaccines (Pfizer & Moderna).
These vaccines contain an instruction (mRNA) which consists of a series of nucleotides that enter your cell. These nucleotides code for amino acids that combine to make a critical part of the virus, the spike protein.

This protein provides the means by which the virus attaches to your cells and is therefore critical to its life cycle. When released from your cell, your immune system recognizes this protein as foreign and makes an antibody against it. Should you contract the infection, your antibodies immediately attach to the spike protein (like a key in a lock) and prevent the virus from attaching to your cell. The immune response invoked by the vaccine also activates T cells that serve as memory cells to prepare your system for the next time it sees the spike protein.

2) Viral Vector Vaccines (Johnson & Johnson and Astra Zeneca/Oxford)
Like the mRNA vaccines, this group gets the instructions for the manufacture of the spike protein into your cell but via a harmless virus (adenovirus). As before, your immune system sees this as a foreign protein & makes an antibody against it. The only difference between these vaccines is that they use different virus vectors.

3) Recombinant Protein (Novavax)
This vaccine involves the manufacture of the entire spike protein and combining them into a small (nano) particle which resembles the virus but without its body (RNA). This is combined with an adjuvant which enhances the immune response. This mixture is the vaccine that is injected. Again, the body sees the protein as foreign and makes an antibody against it.

However, there is a potential problem! The immune system is very specific for the same reason that the key to your house will not open you neighbor’s home and vice versa. The protein (spike in this case) that your body encounters during an infection has to be identical to the protein that produced the initial immune response. So, the lock (viral protein) has to be a perfect match for the key (antibody) that was made for it. Mutations and the variants that arise from them, change the “lock” (spike protein) so the “key” (antibody) derived from the vaccine, is less likely to work or in some cases doesn’t work at all (for example the AstraZeneca/Oxford vaccine vs the S African variant). This will necessitate a reformulation of the vaccine (booster), possibly yearly as is done with the flu vaccine, to accommodate these changes in the spike protein. The good news is that this can easily be done with the mRNA vaccines. I assume that it can be done with the others, but I have not heard how difficult this will be.

    No, as stated above, the vaccines contain only a small fragment (spike protein) of the virus or instructions (mRNA) to direct your cells to make this protein.

    As the vaccines are only 95% effective there remains a 5% chance that you can contract Covid-19.  However, the infection will be blunted by your body’s prompt and directed immune response.  Thus, it is extremely unlikely that you will require hospitalization or die.

    Absolutely not! The only things in the vaccine are the instructions for the spike protein and ingredients that ensure stability of those components.

    No, the vaccines have absolutely no effect on either male or female sterility. Vaccines only interact with your immune system and have nothing to do with your reproductive system. The cells in your body that the vaccines use to make the spike proteins are the same cells in your immune system that are called forth to fight any foreign invader. Your reproductive system is not involved in fighting the flu, strep throat or any other pathogen & it is not involved with this process either.

    Yes, absolutely! Because people have a varied response, it is almost impossible to determine the extent of the immune response following infection. There is some discrepancy, however, on the timing. Many epidemiologists/infectious disease specialists state that you should wait until after your isolation period. This is primarily to protect others. Dr Fauci, has recommended waiting 90 days after the start of your symptoms, feeling that your natural antibodies may blunt your immune response to the vaccine. Personally, I would consider the risk/benefit factors to the patient such as the person’s age and medical status as well as the viral burden in the community. If the patient is old, with multiple comorbid factors and the local positivity rate is high, I would not wait 90 days. The risk is too great.

    Wait a full 90 days because the monoclonal antibodies in your system will bind to the spike protein produced by the vaccine, rendering it ineffective.

    All the major medical organizations involved with women’s health agree that the vaccine should be offered to pregnant or breastfeeding women “who are eligible.” As with most clinical trials, pregnant/lactating women were not included in the  vaccine trials. However, thousands of pregnant women have received the vaccines and no adverse reactions have been reported. Currently, studies are underway that include pregnant women.

    If you are breast feeding you can get the vaccine. In fact, your baby will benefit from Covid-19 antibodies that are present in your breast milk. Click here to learn more

    No. The tests are dependent on obtaining virus in selected areas - i.e., nasopharynx, anterior nose or throat. The vaccine does not contain an intact virus nor do the spike proteins produced get to the areas sampled. All the contents of the vaccine and/or the resultant proteins remain within the body.

    Yes, because the vaccine induces the formation of same antibodies that are detected by the test.

    The majority of the reactions are minor, including local tenderness at the site of the injection, headache, fatigue, mild fever or chills. The majority of these side effects last only 2-3 days & quickly respond to an aspirin or Tylenol.

    Rarely, a severe reaction (anaphylaxis) occurs. The Pfizer vaccine has reported about 11.1 such reactions per million doses & the Moderna approximately 2.5 per million. The median time of onset following the injection was 13min (range 2-150 min) and quickly responds to aggressive and appropriate treatment. 

    This is not a “mild case of Covid” but, rather, it means the vaccine is working and this is the result of your body’s immune response.

    NO! Although this seems like a good idea, anti-inflammatory medications (Tylenol [acetaminophen] or NSAIDS like aspirin, Advil, Motrin [ibuprofen], Aleve [naproxen] can blunt your immune response thereby reducing the beneficial effect of the vaccine. They can be taken AFTER receiving the injection but only if necessary. There is some evidence that this too can blunt your immune response so don’t take these medications unless you have symptoms.

    The CDC is considering allowing people who have had severe allergic reactions in the past to get the J&J vaccine. They are also reviewing if the J&J vaccine can be giving to an individual who had an anaphylactic reaction to the first shot of the Pfizer or the Moderna vaccines and can’t get the second.

    THE ONE YOU CAN GET THE SOONEST! All three of the currently approved vaccines are very effective. Remember, the sooner we all get vaccinated, the sooner we reach herd immunity (70-85% people protected) and the sooner the virus will stop spreading. If the virus can’t replicate, it can’t mutate!!

    YES, if you are not vaccinated!  If you are vaccinated, these precautions are less stringent. Many suggest, if you are indoors, with a large crowd of strangers, you should consider wearing a mask & socially distance. Although the vaccines are extremely effective, we are far from herd immunity. The virus is still in the community and worse, the much more contagious and potentially more lethal variants are spreading rapidly. The Alpha variant (B.1.1.7 variant from the UK) is already the dominant strain in the US. The current vaccines, although slightly less effective against the known variants, still offer excellent protection. But, if the virus finds a susceptible (non-vaccinated) host where it can replicate, it will mutate to circumvent our efforts to block it.

    The only way to prevent this process is to not become a willing host. Thus, get vaccinated and use your best judgement as to whether the social circumstances you are in justify more stringent precautions.

    There is some evidence to suggest that you are less likely to shed virus after completing your vaccination. However, the experts have yet to make a definitive statement as the data is inconclusive at this time.

    No, these vaccines do not contain any aborted fetal cells. However, Pfizer & Moderna did perform tests to prove that their vaccines worked using fetal cell lines.  Johnson & Johnson uses fetal cell lines in vaccine development, confirmation & production.

    But fetal cell LINES are not the same as fetal TISSUE.

    Fetal cell lines grow in a laboratory and were established in the ’70 & ‘80s.  These cells have been cultured over many generations and are sustained by elemental nutrients. They are now thousands of generations removed from the original fetal tissue and do not contain any tissue from a fetus.  Their use in research have saved millions of lives.

    These are references to what church authorities are saying about the vaccines:

    Stay safe and remember we almost have the pandemic under control. But to achieve this objective we must stop the virus from replicating (passing person to person) and this will only happen if we ALL pitch in and get vaccinated.

    REPLICATE OR VACCINATE – it’s your choice.

    G. David K. Hopper, MD
    Associate Clinical Professor of Pediatrics, Emeritus
    Tufts University School of Medicine
    Boston, MA

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