NOTE: The best medical advice will come from a physician that has walked closely with you and your personal specific medical concerns. We would encourage you to establish a Primary Care Physician as you consider the options before you and the effect on your personal situation. The information on these pages is not intended to be medical advice. All individuals should consult with a medical professional regarding their medical decisions.

Scientific research and information is updated regularly, especially now as the scientific community is actively and rapidly researching this novel virus. The data below was posted on August 31st, 2021. 

Vaccine Safety and Efficacy FAQs

What are the vaccines and how were they made?


Vaccines are made of pieces of a virus. Sometimes, it is a virus that has been killed. Sometimes, it is instructions on how to make virus protein. With the viral information, your body trains itself to respond quickly when you are exposed to COVID. Sometimes the training is so effective that you never develop the virus. Even if you do develop the virus, because your body is prepared, the illness is milder.

There are currently three vaccines being distributed and administered in the United States:

  • mRNA (Pfizer & Moderna) - the genetic instructions (in the form of messenger ribonucleic acid) for the spike protein (which COVID uses to break into your cells) are provided to your body and your immune system learns to defend itself from the virus by studying the spike protein. The technology and methodology used in the mRNA vaccine has been in research and development since the 1990s. In the past, the struggle was how to contain the mRNA in a way that your body would not immediately destroy. The mRNA itself was working effectively in past trials. (Christian Medical & Dental Association, CMDA Matters Podcast, "Countering COVID-19 Vaccine Misinformation")
  • Virus Vector (Johnson & Johnson) - an adenovirus that cannot replicate but has been modified to produce spike protein is provided to your body and your immune system uses the spike protein to learn to defend itself. Virus Vector vaccines are the same technology and methodology used in vaccine development since 1798 with the discovery of the smallpox vaccine by Edward Jenner.




The vaccines were developed quickly, is that an area of concern?


Specifically with these vaccines, there were a number of things that worked to the benefit of researchers to bring them to market more quickly

  • Previous research: SARS and MERS are similar to COVID-19. In 2003, there was a vaccine to handle the SARS spike and was moved through clinical trials. The trials ended because the epidemic ended on its own and funding ended. This allowed researchers not to start from scratch- vaccine trials were able to get up and running in March 2020.
  • Money and resources – because of the pandemic spread of COVID-19, there were researchers worldwide working on one disease at one time. Usually, researchers spend years to find funding and build studies piece by piece as they acquire funds via grant processes. During a global pandemic, federal and private funding were amply available.
  • Production timelines- typically, vaccine production (think: buildings, manufacturing materials, etc) would not begin until after a vaccine has been through clinical trials. Because we were in the middle of a global pandemic, the production process and preparation of manufacturing sites began at the same time clinical trials did.
  • High levels of disease – in a clinical trial you’re seeing if the vaccine works or doesn’t work. You need 50% efficacy threshold, which means you need a significant number of people to get infected from your trial to see if they had the vaccine or placebo. With non-pandemic years, you could wait a long time for enough people to catch the virus in question, thus delaying the timeline of the trials. In a global pandemic, that isn’t the case.
  • Increased Clinical Trial Population – Clinical trial phases were overlapped and there were ample participants willing to join in the trial phases. Researchers often spend much of their time finding individuals willing to participate in clinical trials. Because we were in the middle of a global pandemic, there were many willing to participate.

Dr Katelyn Jetelina, MPH, Epedimiologist at UTHealth, "The vaccine got to us incredibly fast."

Additionally, the mRNA technology had been in development for over 30 years. This specific type of vaccine, while new to market, had already been tested in animal studies and had begun human clinical trials prior to 2020.

Reasons to Believe, "The COVID-19 Vaccines and God's Providence (2020)




What does it mean that they were sent to market under an Emergency Use Authorization (EUA)?


The EUA expedites the approval process and allows portions of the process to overlap. It does not diminish the research or clinical trials process of vaccine development. As mentioned above, the vaccines were in development prior to 2020, and robust clinical trials still occured. (Reasons to Believe, "The COVID-19 Vaccines and God's Providence (2020)

EUAs have been used for other public health emergencies in recent years. Manufacturers are able to submit a request for an EUA to the FDA. During this process they are still required to demonstrate safety and efficacy from clinical trials. Once ample data is collected, the EUA request will be taken before an advisory committee for EUA approval. In recent years, EUAs have been utlized for treatment or testing technologies related to Zika, H1N1, Anthrax, and MERS.

You can find the FDA's page on EUA here.

EUA approval is contingent upon:

  • The chemical, biological, radiological, or nuclear (CBRN) agent referred to in the March 27, 2020 EUA declaration by the Secretary of HHS (SARS-CoV-2) can cause a serious or lifethreatening disease or condition.

  • Based on the totality of scientific evidence available, including data from adequate and well controlled trials, if available, it is reasonable to believe that the product may be effective to prevent, diagnose, or treat such serious or life-threatening disease or condition that can be caused by SARS-CoV-2.

  • The known and potential benefits of the product, when used to diagnose, prevent, or treat the identified serious or life-threatening disease or condition, outweigh the known and potential risks of the product.

  • There is no adequate, approved, and available alternative to the product for diagnosing, preventing, or treating the disease or condition.

For more on the EUA process, this document outlines the guidelines for industry seeking EUA approval.

One critique of the EUA is that these vaccines would not be covered under the National Vaccine Injury Compensation Program (VICP) designed to help provide financially for those who experience one of the potential rare risks associated with vaccines.

To address this issue, the COVID-19 Vaccines were approved to be covered by the Countermeasures Injury Compensation Program (CICP), allowing individuals who experience one of the statistically rare risks to file for benefits.

It should be noted that it is anticipated the current vaccines on the market will recieve full FDA approval shortly. There are also a variety of items we consume regularly as a society that aren't FDA approved or regulated, or approved via an EUA.




What about long term impacts or side effects?


Almost all safety issues with vaccines show up within the first 6 weeks. While there are case reports of vaccines with possible long term side effects, statistically significant examples are rare. Vaccines are designed to cause the body to have an immune response and then be eliminated from the body. In the mRNA vaccines, the mRNA is quickly degraded in the body.

The short-term side effects we see are generally from the body amounting the immune response. In order to fight off a virus by producing the memory cells (B-cells) that the body needs to fight off a future infection, it does different things – like produce a fever. Fever, chills, body aches, headaches – the “flu like” symptoms you experience – are your body producing this immune response. These are the most common short term side effects.

Long-term side effects are not fully known at this time. But at the same time, the long-term side effects of a COVID infection are not fully understood either.

You may have heard about some of the clinical trials being paused or investigated with reported side affects.

The J&J trials were paused when it became evident that there was risk of a certain type of blood clot (called thrombosis with thrombocytopenia syndrome), just like the mRNA vaccines came under review when it became evident that there was a risk of myocarditis. The Advisory Committee on Immunization Practices met and reviewed the data, and came to a conclusion which was that the risk of myocarditis, pericarditis, and blood clots was far less than the risk of not vaccinating.

This is an example of the monitoring practices that are in place working to their intended purpose. This can help assuage some fears as these risks were noted, investigated, and reported. If and when other significant side effects are seen, they will go through a similar review process. (U.S. Department of Health & Human Services, "Statement Following CDC ACIP Meeting from Nation’s Leading Doctors, Nurses, Pharmacists and Public Health Leaders on Benefits of Vaccination").

While it is true that some individuals will respond to the vaccine with side effects, it is helpful to put those numbers in context.

From the data we have as of August 2021:

  • For the Johnson & Johnson vaccine, if you’re a woman 18-49, there’s a 28 in 8,000,000 chance of developing blood clots.
  • For the Modern / Pfizer vaccines, if you’re a young person, there’s a 13 in 1,000,000 chance of having myocarditis or pericarditis.
In the next section, you can compare some of these known risks of the vaccine to the known long term impacts or death of COVID-19 infection.




How do these potential side effects compare to the side effects of being infected with COVID-19?


From the most current data we have, about 1-3 in 10 people with COVID will have long term symptoms. Long term symptoms, currently referred to as “Long COVID” can look a variety of ways and aggravate a variety of issues; these include headaches, brain fog, fatigue, memory issues, continuation of loss of sense or smell, reduction in lung capacity, and damage to organs including the heart, kidneys, and liver. It is important to note, that long term symptoms can occur even after mild or moderate disease. (Mayo Clinic, "Coronoavirus Long Term Effects, Risk based on age group of dying from infection of COVID-19., European Journal of Epedimiology, Levin, Hanage, Boaitey, Cochran, Walsh, Katz, "Assessing the age specificity of infection fatality rates for COVID-19" (2020).).

While COVID-19 is a respiratory illness, the ACE2 Receptors of the virus can also attach to a variety of organs and systems in the body. This is why we have seen neurological impacts (such as “brain fog”, migraines, loss of taste and smell) and side effects in other body systems (blood clotting particularly in pregnant women). This is an area that will continue to be researched and treatment options will be considered and develop with time. If you are experiencing Long COVID we would recommend finding a PCP you trust to track with as the data develops.

Another rarer long-term sequelae of COVID is a condition called MIS or multisystem inflammatory syndrome. This occurs more often in children, although adult cases have been reported. MIS is an abnormal immune response that occurs after the patient has been infected with the SARS-CoV2 virus, even if the infection is mild.

Source: Dr. Susanna Esposito and Nicola Principi. Internal Journal of Biological Sciences, “Multisystem Inflammatory Syndrome in Children Related to SARS-CoV-2.”

Devastatingly, and perhaps most obviously, this illness is killing many individuals who are infected by it. Based on the most recent meta-analysis done on fatalities and age ranges, the following represents risk based on age group of dying from infection of COVID-19.

*Numbers rounded to their nearest round number.

*https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721859/

*You can view the full chart here.

Study: European Journal of Epedimiology, Levin, Hanage, Boaitey, Cochran, Walsh, Katz, "Assessing the age specificity of infection fatality rates for COVID-19" (2020).

From the above, current data, it is fair to conclude that statistically the likelihood of long term impacts or death from COVID-19 infection far outweigh the likelihood of long term impacts or death from the vaccines.




Who is the vaccine available to and recommended for?


As of August 2021, the Pfizer vaccine have been approved for individuals 12 years and older, unless there is a contraindication. (FDA, "Pfizer-BioNTech COVID-19 Vaccine")

For Moderna and Johnson & Johnson, the vaccine has been approved for individuals 18 years and older. (FDA, "Moderna COVID-19 Vaccine", "FDA, "Janssen Covid-19 Vaccine")




Who should talk to their doctor about getting the vaccine?


Everyone should discuss their unique situation with their doctor. Anyone with concerns about their medical history or underlying conditions should discuss their unique situation with their doctor.

Individuals who have had COVID complicated by multisystem inflammatory syndrome (MIS) should discuss with their doctor prior to vaccination.

Individuals who have had a severe allergic reaction or anaphylaxis to the vaccine or something in the vaccine should consult with their doctor prior to vaccination.




Is the vaccine recommended for pregnant women?


If you are pregnant you should discuss vaccination with your OBGYN as he or she would know the details of your medical history and current situation.

As of August 2021, the data suggests two important factors to consider in this decision. First, we have seen a high number of pregnant COVID-19 patients, with more severe disease and complications. This is not surprising as pregnancy can be considered an immunosuppressed state – meaning you are at a higher risk of any infection than when you are not pregnant.

Second, both the American College of Gynecology and the Society of Maternal Fetal Medicine recommend the COVID-19 vaccination for pregnant women. Many pregnant women have already been vaccinated and have not reported a higher incidence of complications than the average population. However, it should be noted that pregnant women were not included in the original study. This is not an uncommon practice due to the ethics of experimenting on pregnant women. (CDC, "COVID-19 Vaccines While Pregnant or Breastfeeding")

Some respected physicians would recommend waiting until after the first trimester, as during the first trimester the baby is in a stage of rapid growth and is more fragile to most medical interventions. (SmartHerNews, "Natural Immunity & COVID-19?")




Is the vaccine necessary if I’ve already had COVID-19?


We do know that vaccine immunity is more targeted to the spike protein (how the virus enters the cell) than natural immunity. However, we are still trying to collect evidence on how long immunity from a previous infection will last, just like we are collecting evidence on how long immunity from the vaccine will last. We can also look to a different vaccine for wisdom. Some of millennials had varicella (the chickenpox) naturally and some have had a vaccine for varicella. We know from blood titers of immune cells, that sometimes the titers from natural immunity are not as high as those with the vaccine and sometimes they are. However, we can’t know this without drawing the titers. This is another area that data and evidence will grow in as time goes on.




It doesn’t seem like the vaccine is effective, so why should I get it?


This can be confusing because the information does change often. Vaccines are designed to protect you from contracting the illness and/or from having severe morbidity or mortality from an illness. They are also designed to protect those around you. As of August 2021, three studies have shown that the vaccinated can carry the same infectiousness as the unvaccinated, while another study has shown that the vaccinated are less infectious. Even with these two studies, the vaccine has shown successful efficacy against both mild and severe disease, which will help hospital capacity. While reinfection is possible, being vaccinated reduces the liklihood of hospitilization.

It is also important to note that SARS-CoV2 will never be eradicated. The vaccine will not provide sterilizing immunity, the way the measles vaccine does, just like a COVID infection will not provide sterilizing immunity, the way a measles infection does. This is due to two important concepts. First, SARS-CoV2 is a zoonotic virus, meaning it lives in some of the animals around us and therefore there is a constant supply of the virus. Unless we eliminate this supply it won’t go away completely. (Jo WK, de Oliveira-Filho EF, Rasche A, Greenwood AD, Osterrieder K, Drexler JF. "Potential zoonotic sources of SARS-CoV-2 infections." 2021).

Second, SARS-CoV2 is a mucosal virus which means that it lives and causes disease in your mucosal tissues – your nasal and bronchial passageways. Most of the memory cells your immune system is producing live in your blood stream. Therefore, you may have some mild symptoms before your body begins to fight off the virus.




Do the vaccines cause infertility? Where did this information come from?


There has been some misinformation spread regarding fertility and the vaccine. As with most misinformation, it started with a grain of truth. First, the spike protein produced by the mRNA attaches to the ACE2 receptor. This receptor is found throughout your body, including in the female reproductive organs. Second, after vaccination, there were several reports of abnormal or heavy menstrual bleeding. This can be disconcerting but can be caused by any immune response in your body – which is what the vaccination is designed to do, cause an immune response in order to produce memory cells. Menstrual bleeding can also be heavy or abnormal due to a stomach virus, influenza infection, or even stress. So far, research has not shown any effects on female fertility from the vaccine.

In fact, it should be noted that there have been questions on whether an infection with SARS-CoV2 can cause fertility issues. (George Anifandis, et al. “COVID-19 and fertility: a virtual reality.” Reproductive Biomedicine Online)




Do the mRNA vaccines affect my DNA?


Your own body produces RNA from DNA which is housed within the nucleus of your body’s cells; then the RNA is used to produce any protein your body may need. The mRNA from the vaccine is used to produce the spike protein through the same route your own body produces protein. In both cases the production of the protein is done in the cytoplasm of the cell and not the nucleus of the cell. The mRNA from the vaccine does not need enter the nucleus of your own body’s cells and therefore does not interact with your DNA.

(Park, Jung Woo et al. “mRNA vaccines for COVID-19: what, why and how.” International journal of biological sciences vol. 17,6 1446-1460. 10 Apr. 2021).




If I am not in a high risk category or around high risk people, why should I consider the vaccine?


While the mortality rate for COVID has remained relatively low, many (10-30% of people who contract COVID) experience long term effects from the virus. While the risk for death may be low for some individuals, the risk of having long term effects from COVID is real and much greater than possible long term effects from the vaccine. See the information above regarding Long COVID risks.

Moving from personal risk, another reason to consider vaccination is to love others well. There are many who are medically unable to take the vaccine due to pre-existing conditions or socio-economic limitations, and public spaces are unsafe for them at this time. If there was wider spread herd immunity these individuals would be much safer. Additionally- you may not realize if/when you are around a higher risk individual. There are many in socioeconomic situations that are forced to work in public facing positions right now despite their health status. As they fill service rolls throughout the city, their interactions with the general public can bring greater risk due to the low herd immunity rates.

While there may be a small risk to most individuals to take the vaccine, there are some parts of the population that are experiencing a high risk to be around others.




What do we know about vaccine safety so far?


Any kind of medical intervention has risks associated with it. Even the Tylenol you take for a headache or the Neosporin you put on your scraped knee has a risk. When making medical decisions, you have to consider if the benefits outweigh the associated risk.

One way we can have high confidence in these vaccines is the high volume of use thus far. In clinical trials, the Pfizer vaccine had 43,000 participants, Moderna vaccine had 30,000 participants, and J&J had 43,000 participants. Typical clinical trials have closer to 1-5,000 participants.

This larger sample size gives us a more accurate view into how the general population will respond to the medical intervention. Participants are monitored at regular intervals for two years. Admittedly, this two-year mark has not ended yet, but so far, the data has been promising.

Also it is important to note, that in the past, long-term side effects from vaccine studies have been noted within the first several months after administration (Christian Medical & Dental Association, CMDA Matters Podcast, "Countering COVID-19 Vaccine Misinformation).

Since clinical trials, over 167 million Americans have been fully vaccinated (CDC, Data Tracker). Again, this is a very large sample size from which to learn.

From what we have been able to learn of the vaccine so far with the large dosages given, they are considered safe. The most common side effects people experience include pain at the injection site or temporary signs of an activated immune system (tiredness, headache, muscle pain, chills, fever, nausea - discomfort at the injection site) when they get the vaccine.

Like with any injection, some people (usually those who have had an allergic reaction in the past) can have a severe allergic reaction. Statistically, this is rare and treatable.

Two primary ways that healthcare workers and researchers help to mitigate these potential risks include informed consent and CDC reporting.

  • Informed Consent – when you go to get the vaccine, you’ll receive an insert with a list of information about potential health history concerns that could cause a reaction with the vaccine. It is important to make sure you understand the risk you are taking on and feel confident the vaccine is a good option based on your specific medical situation. If you have any medical history concerns, you should consult with a Primary Care Physician before receiving the vaccine.
  • CDC monitoring – the CDC monitors adverse effects in two ways: passive reporting through VAERS and active monitoring through V-safe. VAERS is a database where anyone can report a side effect. When that side effect is deemed above and beyond what is expected with a temporary activation of your immune system (fever, chills, etc.), someone from the CDC will contact the person who reported for further work-up. It is worth noting that VAERS data posted on this forum is unverified. Please review the data limitations posted by the CDC on their site. V-safe is the CDC’s active monitoring. Once someone receives a vaccine, they are given the opportunity to enroll in the program. They are then texted questions on a regular basis where they can easily report any side effects they have experienced ( Dr Katelyn Jetelina, MPH, Epedimiologist at UTHealth, "VAERS Data...take it with a grain of salt.")





*The choice to get vaccinated is a personal one, and will best be made between an individual and a primary care physician who knows their health history well. The information on these pages is not intended to be medical advice. All individuals should consult with a medical professional regarding their medical decisions.*