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Covid-19 mRNA Vaccines – A Cautionary Tale

Several people have asked me what I think of the Pfizer and Moderna Covid-19 vaccines and whether I think they should get them. At this point I do not think there is enough information about the vaccines to give truly informed consent. The vaccines were only studied for two months and did not address the crucial question of whether they reduce one’s chance of carrying and spreading the virus. For those with chemical sensitivities, who are also often drug intolerant, the vaccines could pose a significant risk, which needs to be weighed against the benefits.

The research studies showed that these vaccines do reduce the risk of getting sick from Covid-19, but they did not provide conclusive evidence to support the reasons most people want to get vaccinated – to keep from dying from Covid-19, to get back to a more normal life, and to stop wearing masks. Thus, despite all the hype about the vaccines, they are not the “get out of jail free card” that many wish they were.

According to the Centers for Disease Control & Prevention (CDC), 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, and washing hands often.

For those who are able to safely shelter in place, it seems reasonable to take a wait and see approach before deciding whether to get vaccinated. I believe that in 6-9 months there will be much more information available on which to make an informed decision about this. On the other hand, for those who must work in an indoor space where they are frequently exposed to other people, it seems reasonable to conclude the benefit of the vaccine likely exceeds the risk – although this would need to be decided on a case-by-case basis.

Before making a decision about whether to receive a Covid-19 vaccine, it is important to consider the following:

1. What is your risk of being exposed to Covid-19? How much time are you around other people? Do you work indoors or are you safely sheltering in place? Do you live in a large family group? Do you travel?

2. What is your risk of getting severe disease? How old are you? Do you have underlying medical conditions?

3. How likely are you to have an adverse reaction to the vaccine? Have you had reactions to past vaccines? Other medications? Do you have an allergy to polyethylene glycol (PEG)? Do you have an autoimmune disease?

Messenger RNA (mRNA) Vaccines

Both the Pfizer and Moderna vaccines are the first messenger RNA (mRNA)-based vaccines to be approved by the FDA. Conventional vaccines use antigens associated with an infectious agent to stimulate the immune system. mRNA vaccines take an extra step. The mRNA tells your body’s cells to make the Covid-19 spike protein which then triggers an immune response. The vaccines are injected into the deltoid muscle of the upper arm and are thought to primarily collect in the lymph nodes of the armpit where they elicit an immune response. This immune response includes immune cells as well as antibodies. Note that these vaccines do not contain a full copy of the virus so there is no risk of person becoming infected with Covid-19 by being vaccinated.

These vaccines consist of mRNA wrapped in a small fatty envelope called a lipid nanoparticle. Salts, sugar (sucrose protects vaccine during freezing), and buffers to balance the pH are also added. The outside of the particle is covered with polyethylene glycol (PEG), which is a petroleum-based hydrocarbon. Ethylene glycol is a toxic chemical used as antifreeze. When strung together as PEG, it is less toxic and found in many drugs and foods. Of note is that people with chemical sensitivities often are intolerant of drugs and processed foods.

Neither vaccine contains eggs, gelatin, or latex. Neither do they contain a preservative like mercury that can be found in other vaccines. Mercury (thimerosal) is used in some vaccines to prevent bacterial contamination in multi-dose vials that are used over time.  Although multiple doses of the Pfizer and Moderna vaccines come in each vial, they must be used within 6 hours after the first dose is withdrawn, so there is little chance of bacterial growth and no need for a preservative. 

A full list of ingredients in the Pfizer and Moderna vaccines can be found here.
(Appendix B)

Efficacy of Pfizer and Moderna Vaccines

Articles about the Pfizer and Moderna vaccine studies were recently published in the New England Journal of Medicine (NEJM).

Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine” by Pfizer researchers was published on December 10, 2020.

The Moderna study, “Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine” was published on December 30, 2020.

The Pfizer study enrolled almost 44,000 participants, who were evenly divided between those receiving the vaccine and those receiving a salt water placebo. The vaccine series consisted of two doses given 3 weeks apart.

The researchers found there were 8 cases of Covid-19 (that started at least 7 days after the second dose) among those who received the vaccine and 162 cases among those who received the placebo. Based on this data they concluded the Pfizer vaccine was 95% effective in preventing symptomatic Covid-19 infections.

These results are impressive, but one must bear in mind that it is well established that studies funded by the pharmaceutical industry are more likely to be associated with statistically significant pro-industry findings than studies conducted by independent researchers.

Among 10 cases of severe Covid-19 (with the onset after the first dose), 9 occurred in placebo recipients and 1 in a vaccine recipient. This provided preliminary evidence of possible vaccine-mediated protection against severe disease, although the numbers were too small to prove this. Of note, there were no Covid-19 associated deaths in either arm of the study, so no conclusion can be drawn as to whether the Pfizer vaccine is capable of reducing Covid-19 deaths.

The Moderna study enrolled a little more than 30,000 volunteers, who were evenly divided to receive the vaccine or a placebo. The vaccine series consisted of two doses given a month apart.

Symptomatic Covid-19 illness was reported in 185 participants in the placebo group and in 11 participants in the vaccine group. This resulted in an overall vaccine efficacy of 94.1% in preventing symptomatic Covid-19 infections. But in research subjects 65 years or older, the efficacy was only 86.4%.

Unlike the Pfizer study that required laboratory confirmation of a Covid-19 case, the Moderna study counted cases that had at least two of the following symptoms: fever, chills, myalgia, headache, sore throat, or new olfactory or taste disorder. Except for changes in smell and taste, the other symptoms are common to the flu or other viral infections and participants with these symptoms may have been erroneously counted as being caused by Covid-19.

On the other hand, the Moderna study, as compared to the Pfizer study, focused more on whether its vaccine could prevent severe Covid-19 infections. The researchers found that severe Covid-19 occurred in 30 participants in the placebo group and none in the vaccinated group. This is strong evidence that the Moderna vaccine can prevent or reduce severe Covid-19 illness. But since there was only one death in the study (also in the placebo group), there is insufficient data to determine whether the Moderna vaccine can reduce one’s chance of dying from a Covid-19 infection.

Safety of Pfizer and Moderna Vaccines

Not surprisingly, both studies tend to minimize adverse reactions to their vaccines, even though 80-89% of vaccinated subjects developed at least one local symptom (e.g., pain, swelling, or redness at the injection site and/or swollen lymph nodes in the armpit of the vaccinated arm) and 55-83% developed at least one systemic symptom, such as fever, fatigue, headache, chills, and muscle or joint pain.

These side effects were considered mild to moderate and were stated to resolve within a few days. But one drawback of the studies is that participants were only followed for 2 months. The NEJM editorial that accompanied the Pfizer article asked important questions – will additional vaccine side effects emerge with longer follow-up, and will unexpected safety issues arise when the number of those vaccinated grows to millions, and possibly billions, of people.

Case in point, both studies stated there were no anaphylactic reactions among their study participants, but there have been numerous reports of severe allergic reactions occurring in members of the public who have received their vaccines. One reason the studies may have missed this potential side effect is because both studies excluded people with a history of allergies to components of the Covid-19 vaccine and those who previously had a severe adverse reaction to any vaccine. This may have excluded many chemically sensitive individuals.

Many feel the likely cause of anaphylactic reactions to mRNA vaccines is a hypersensitivity to the polyethylene glycol (PEG) coat on the vaccine nanoparticle. It is interesting to note that the mechanism of PEG hypersensitivity does not involve IgE, the antibody type that causes classic allergic reactions. For this reason, a hypersensitivity to PEG is sometimes referred to as an “anaphylactoid” or “anaphylactic-like” reaction. People with chemical sensitivities are no strangers to having unusual reactions to chemicals and drugs. According to current guidelines, no person with a history of an immediate allergic reaction to PEG (or polysorbate, which cross reacts with PEG) or any other component of the vaccines should be vaccinated.

Although concerns have been raised, It is unclear whether those with a history of Guillain-Barre syndrome or Bell’s palsy are at increased risk of having an adverse reaction to the vaccines.

It is also concerning that mRNA vaccines might induce an autoimmune response.  According to a 2018 article entitled “mRNA Vaccines – a New Era in Vaccinology,” potential safety concerns about mRNA vaccines include local and systemic inflammation, the biodistribution and persistence of expressed immunogen (in Covid-19 case the spike protein), and the stimulation of auto-reactive antibodies.

There is increasing evidence that autoimmunity is playing a part in severely ill hospitalized Covid-19 patients and “long haulers”. Autoimmunity is when a person’s immune system attacks parts of one’s body. According to the CDC, no data are currently available on the safety and efficacy of mRNA Covid-19 vaccines in persons with autoimmune conditions. Autoimmune diseases include Type 1 diabetes, rheumatoid arthritis, multiple sclerosis, systemic lupus, Crohn’s disease, ulcerative colitis, Hashimoto’s thyroiditis, celiac disease, and psoriasis, to name a few. These conditions, especially Hashimoto’s thyroiditis, are not uncommon in individuals with multiple chemical sensitivities (MCS).

Last, but not least, there are risks associated with nanoparticle drug delivery systems. Because of their small size they have the potential for crossing various biological barriers in the body, including the blood brain barrier.


I am convinced by the Pfizer and Moderna studies that their vaccines reduce symptomatic Covid-19 infections. They also likely reduce serious infections to some extent, and may reduce deaths from Covid-19, though this has yet to be proven.

But many questions remain. How will the vaccines perform in children, pregnant women, and immunocompromised individuals? How long does the vaccine’s effect of suppressing symptoms last? How long does immunity after a Covid-19 infection last? Can the vaccines reduce fatalities? Will widespread vaccinations create more asymptomatic carriers who can unknowingly spread the disease? What side effects may appear over time or what new side effects may appear after millions of people are vaccinated? Will the vaccines be effective against variant strains of Covid-19?

I think the vaccine studies done to gain FDA approval were a good start, but they only went so far. Instead of the next studies being done in controlled clinical settings, they are being done in the real world. With the rollout of the Covid-19 vaccines, the public at large has become research subjects in a massive human experiment. At least for now, it is up to each of us to decide if we want to participate in this experiment or wait for more information before deciding whether to get vaccinated. I do not think there is a right or wrong answer. Each person needs to carefully weigh the risks and benefits of being vaccinated based on their individual circumstances. In the end, I hope we find that the Pfizer and Moderna vaccines exceed all our expectations for reducing illness and stopping the pandemic, but only time will tell.