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Understanding the COVID-19 Vaccine and FAQs: A Mega Thread
Many of you responded to my tweet about the COVID-19 vaccine. I didn't forget to respond to everyone's questions - I decided it would be much easier to explain it thoroughly and answer everyone's questions in one thread. Background: I'm a GT grad student in biomedical engineering
For the purposes of this thread, I will be focusing on the Pfizer vaccine. The Moderna vaccine, which just received FDA clearance today, utilizes mRNA as well and has the same efficacy (~95%). The main difference is the Moderna vaccine can be stored at a higher temperature
Q: How do mRNA vaccines work?
Many people think mRNA vaccines are "new". However, their concept has been around for roughly 20+ years. It's only recent developments in technology that allowed us to finally break through and use them for a vaccine. Vaccines create immunity by
Many people think mRNA vaccines are "new". However, their concept has been around for roughly 20+ years. It's only recent developments in technology that allowed us to finally break through and use them for a vaccine. Vaccines create immunity by
introducing the body to a virus' antigens - molecules on the outside of the virus that trigger an immune response. Antibodies target these antigens. Each antibody is specifically produced by the immune system to match an antigen after coming into contact with it. Vaccines
create this contact by injecting a weakened or dead version of the virus (aka polio & measles vaccines) or the antigen itself (aka Hep C) It won't make you sick but allows the body to recognize and thus fight off the virus if it ever comes into contact with it again.
Problem: Creating those vaccines can take a long time. Enter: mRNA vaccines. These vaccines do not use any parts of the virus at all. Instead, it gives the body the instructions (mRNA) to make the antigens of the virus. Once injected, the immune cells make the antigens and
display them on the outside of the cell. The immune system recognizes there is an invader and mounts a response, creating antibodies for that antigen, thus protecting you from future infection. Benefit: Because they don't involve growing or injecting any part of any virus, they
can be developed very fast. They are also easier to scale up & manufacture. This has been the future of vaccines for some time - but with the high stakes of the pandemic the future was pushed to now. Here is an excellent review of them in Nature from 2018: https://www.nature.com/articles/nrd.2017.243
Q & A: How was FDA clearance achieved so quickly and how much testing was really done?
As stated above, these mRNA vaccines are already much quicker to develop and carry less risk. However, given the circumstances, the FDA allowed Phase 1, 2, & 3 clinical trials to be done in
As stated above, these mRNA vaccines are already much quicker to develop and carry less risk. However, given the circumstances, the FDA allowed Phase 1, 2, & 3 clinical trials to be done in
parallel in one large trial. It's also worth noting it was cleared for emergency use. The FDA may issue an emergency use authorization when certain criteria are
met, which includes that there are no adequate, approved, available alternatives and there is enough safety data.
met, which includes that there are no adequate, approved, available alternatives and there is enough safety data.
Pfizer partnered with BioNTech, a group out of Oxford that helped developed an mRNA vaccine for MERS, another coronavirus. So they tweaked it for COVID-19. For the clinical trial, a total of 43,548 participants (age 16+) underwent randomization of whom 43,448 received injections:
21,720 with vaccine and 21,728 with placebo. There were 8 cases of Covid-19 with onset at least 7 days after the 2nd dose among participants assigned to receive the vaccine and 162 cases among those assigned to placebo; Thus the vaccine was shown 95% effective. This is a similar
efficacy rate for most vaccines we take as children. The flu shot on the other hand has an efficacy rate of only 60%. i.e. why many people get the flu even after getting the flu shot. The trial was done across 155 locations in the US and participants monitored for 2 months after.
Link to clinical trial: https://pubmed.ncbi.nlm.nih.gov/33301246/
Q: What are the side effects?
Side effects that have been reported include:
injection site pain
tiredness
headache
muscle pain
chills
joint pain
fever
injection site redness/swelling
nausea
swollen lymph nodes (lymphadenopathy)
Many of these side effects are simply your immune
Side effects that have been reported include:
injection site pain
tiredness
headache
muscle pain
chills
joint pain
fever
injection site redness/swelling
nausea
swollen lymph nodes (lymphadenopathy)
Many of these side effects are simply your immune
system mounting its response. In fact, you are more likely to have side effects if you are younger, as your immune response is more robust. Alas.
Q: Is there anyone who shouldn't get the vaccine?
Only people who have an allergic reaction to any ingredient in the vaccine
Q: Is there anyone who shouldn't get the vaccine?
Only people who have an allergic reaction to any ingredient in the vaccine
(list in tweet below). But, those who have a fever, have a bleeding disorder/on a blood thinner, are immunocompromised, or are pregnant/nursing should talk to their doctor about it first.
Q: What is the vaccine ingredient list?
Q: What is the vaccine ingredient list?
mRNA, lipids (aka specific types of fat molecules), potassium chloride, monobasic potassium
phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose. If you want to get specific on the type of lipid molecules, check the FDA fact sheet: https://www.cvdvaccine-us.com/images/pdf/fact-sheet-for-recipients-and-caregivers.pdf
phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose. If you want to get specific on the type of lipid molecules, check the FDA fact sheet: https://www.cvdvaccine-us.com/images/pdf/fact-sheet-for-recipients-and-caregivers.pdf
Q: Will the vaccine interact with my medications?
Most likely no. The incidence of adverse events during the trial was low and similar among the vaccine and placebo groups. Plus the route the mRNA vaccine takes makes it extremely unlikely. But as always, talk to your doctor.
Most likely no. The incidence of adverse events during the trial was low and similar among the vaccine and placebo groups. Plus the route the mRNA vaccine takes makes it extremely unlikely. But as always, talk to your doctor.
Q: How long will the vaccine provide immunity?
Right now, it still isn’t clear how long immunity lasts following infection. We haven't studied it long enough! But what we do know is that the ones who took the first injections in March are still protected and most coronavirus
Right now, it still isn’t clear how long immunity lasts following infection. We haven't studied it long enough! But what we do know is that the ones who took the first injections in March are still protected and most coronavirus
vaccines have been showing protection for 3-4 years. There are a lot of factors that play into it, so in the end, we will have just have to see. But should be long enough to slow the curve and break the pandemic 
. Article: https://news.ncsu.edu/2020/12/vaccine-safety-skepticism-protection/
. Article: https://news.ncsu.edu/2020/12/vaccine-safety-skepticism-protection/
Q: How many people need to be vaccinated for herd immunity?
We don't know yet... but based on more infectious disease models and other similar coronaviruses, probably between 70-80%.
We don't know yet... but based on more infectious disease models and other similar coronaviruses, probably between 70-80%.
Q: When will I be able to get the vaccine?
The vaccine rollout will prioritize healthcare workers first, followed by critical services & vulnerable populations. Healthy people go last. If you're a healthy person, the expected timeline is April/May, but we'll see.
The vaccine rollout will prioritize healthcare workers first, followed by critical services & vulnerable populations. Healthy people go last. If you're a healthy person, the expected timeline is April/May, but we'll see.
Woo boy this was a THREAD. I'm beat. If there are any other questions, post them below! I'll get back to you as soon as I can. Hopefully, this explanation helps address your vaccine concerns. In the meantime... mask up, social distance, and stay safe Twitter fam! Goodnight 
