With March 11, 2021 being the official one year mark since COVID-19 gained pandemic status, we are all hoping that the end is in sight. Currently, there are three vaccines on the market to protect against SARS-CoV-2 that causes COVID-19. Here we address common questions: Are the vaccines safe? Does the science back up it’s claims? The short answer is “Yes,” top scientists around the world have partnered with the financial backing of big pharma to pull off vaccine development in a single calendar year!
Two different classes of vaccines available now are mRNA vaccines: Pfizer & Moderna; and DNA vaccine: Janseen (Jonhson & Johnson). All three have gained FDA emergency use authorization (EUA) and more candidates are soon to follow.
Find your way around:
What is in the vaccines?
Pfizer and Moderna
Both vaccines only contain three components: Lipids (fats), mRNA (specific to the virus), and saline (matching your bodies natural state)!
The vaccine is based on a SARS-CoV-2 spike glycoprotein (S) antigen encoded by RNA formulated in lipid nanoparticles (LNPs).
Pfizer FDA Briefing
mRNA-1273 is a novel messenger ribonucleic acid (mRNA)-based vaccine encapsulated in a lipid nanoparticle (LNP) against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).
Moderna FDA Briefing
LNPs are basically tiny drops of fat. These droplets prevent the mRNA from being chewed up before it makes it into your cells. The fat allows it to pass through your cell membranes. Once inside the mRNA is active for about two days as it is released.
Janseen (J&J)
This is a DNA based vaccine which is similar to the standard flu vaccine. Scientists take a virus (adenovirus: Ad26 vector), hollow it out and then add in DNA for the Spike proteins from SARS-CoV-2. For example, see number two on the figure below.
Aside from the spike protein SARS-CoV-2 spike protein, the vaccine also contains the following ingredients that help maintain stability and effectiveness at warmer temperatures (such as 4C rather than -80C storage).
Inactive ingredients: citric acid monohydrate, trisodium citrate dihydrate, ethanol, 2-hydroxypropyl-β-cyclodextrin (HBCD),
Janseen FDA Briefing
polysorbate-80, sodium chloride
Are the vaccines giving me a live virus?
No. Both mRNA and DNA vaccines contain genetic fragments specific to the spike proteins of SARS-CoV-2. This protein is how the virus is able to attach to and then enter your cells. As a result, your muscle cells (the site of injection) are given the instructions they need to make the spike proteins that are sent to the cells surface and your immune system can start to recognize them.
Is it safe?
In one word, Yes.
If you are concerned about the rapid pace at which this vaccine was produced, you are not alone! I was skeptical at first until I started to dive into the science. A lot of the safety attributed to the vaccine goes back to the type of vaccine.
Brief look at synthetic mRNAs
In 2018 a review article was published about the rise of synthetic mRNA as a therapeutic in the field of regenerative medicine. Biotechnology companies have already been working on the methods to produce mRNA in a lab setting with a mention of vaccine development as early as 2011! (see sources below)
So the technology is not as new as the media sometimes makes it out to seem!
mRNA Safety Data
mRNA itself is known to be a short term mode of communication for the cell to produce proteins in response to current needs. However, the vaccine only includes instructions (mRNA) for a portion of the virus. These are active shortly after injection, but is gone after about two days. Fortunately, there is no long term worry about mRNA interfering with the body. The reason being that once it’s gone, there is no way for your cells to make more!
In addition, for any company to receive an EUA, they have to provide a minimum of 2 months of data associated with a clinical trial. This is the time span that most vaccines that have issues with safety typically arise.
Viral Vector Safety Data
This technique has been used by Janseen to create vaccines for Ebola, HIV, Malaria, and other viruses of interest. The viral vector has no evidence that is can infect any non-human animals. “As of 31 December 2020, Ad26-based vaccines have been used to vaccinate 193,831 participants in clinical studies and vaccination programs. Overall, these vaccines have been shown to have an acceptable clinical safety profile to date.” (FDA Briefing with Janseen)
Similar to the mRNA vaccines, this vaccine poses no long-term risk to the individual because vector lacks the tools to interact with our DNA to make permanent changes.
Do you carry an EpiPen?
After nearly 70k doses being administered for Pfizer the only serious issues occurred in those who had severe allergic reactions. If you are an EpiPen carrier you should consult with your Doctor before receiving the vaccine. In rare cases anaphylaxis can occur, so close monitoring is necessary to provide the appropriate treatment.
Janseen has also shown individuals with non-fatal allergic reactions to the vaccine. However, after 21k doses, adverse medical events only occurred in less than 2% of cases.
What symptoms will I get?
The purpose of the vaccine is to create immune memory cells (B and T cells). For instance, these cells will create antibodies that will attach the virus quickly the next time it sees it. Antibodies are the way that our body tags harmful cells that need to be removed. That being said, when you get any kind of vaccine it is typical to see swelling, redness, and potentially a fever. This is your body recognizing that something bad has been detected and is your body mounting an immune response. Both mRNA and DNA vaccines are expected to cause similar symptoms.
Does it work?
Pfizer
Yes. Pfizer requires two doses spaced 28 days apart and can achieve up to 95% protection, but must be stored in a deep freezer (-80deg C). This means that out of 20 people who receive both doses, only one of them will become infected when exposed to SARS-CoV-2. Their FDA briefing also includes results about case severity. Priming the immune system with the mRNA can lead to a quicker response upon infection. Two weeks after the second dose, only one severe case was noted out of over 17k participants (Phase 1 clinical trial: healthy adults age 18 to 55). Pfizer has enrolled individuals over 55 for the current Phase 2/3 testing, aiming to include 40% of participants from this age group for continued testing.
In addition, when testing individuals who had the vaccine for antibodies, they had the same response as those who were actually infected. While there is limited data on how long the vaccine offers protection, the minimum is set at three months. Participants from clinical trials will continue to be monitored and this time line will be extended in the future. For health-care professionals this means that receiving a dose now could potentially protect them through the end of the flu season and possibly longer.
Moderna
Yes. Initially, two weeks after the first dose there is about 52.4% protection against a severe case. Finally, with completion of the second dose the protection increases to 92.1% after two weeks. This vaccine is required to be stored in a normal freezer (-20 deg C). This vaccine can be used at pharmacies and hospitals, but does require individuals to come back for the second dose.
Janseen
Yes. This vaccine in a single dose offers 66% protection, two weeks after vaccination, from a severe or critical COVID-19 case. Some researchers say that this is better than the mRNA vaccines because it is a challenge to get individuals to return for the second dose. In addition, this may be the best option for rural areas where freezer storage is not available. These DNA vaccines can be kept on ice and transported out into the community and with the added convivence that you don’t need to come back for a second does. Remember that 66% protection is better than 0% protection.
Over the next couple months more people will become eligible to receive the vaccine. The definition of front-line workers is expanding and more high-risk groups are being added, so check out the CDC for the latest updates on eligibility. However, for those in low risk groups, expect vaccines to become available during the summer of 2021.
A final note:
Because the vaccine isn’t 100% effective, it is important to continue to physically distance, wear masks when around people who are potentially infectious, and as always wash your hands! As more of the population become immune or vaccinated we will approach herd immunity. However, this will take time, so we need to be patient even during 2021. More varieties of vaccines will become available overtime and this will help to get more doses out to the general population.
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Resources:
- What is in the vaccine:
- 2018 ScienceDirect source:
- 2020 Science Direct source:
- 2011 Pubmed source:
- Video walk through of the new vaccines:
- Image credits: Hatice EROL, Arek Socha, febrian eka saputra from Pixabay
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Update: Mr TSC has successfully received his second dose of the Pfizer vaccine and passed the two week incubation period! Yes, there were some minor side effects similar to other vaccines, but his full vaccination helps to protect the two of us. Glad that he had the opportunity to be a part of the early wave of vaccinations! Those over 65 and in high-risk jobs should have access now.