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Covid Vaccine FAQ Part 3: Vaccine Safety

Updated: Jul 31, 2021

This is Part 3 of a multi-part series. Part 1 covers foundational information about how the vaccines work and common questions / myths related to vaccine technology. Part 2 covers questions regarding ingredients and potential toxicity. The information in this current post may be easier to understand after reading Parts 1 and 2 (links below).

In this section I will cover questions related to vaccine safety.

If you would like to navigate directly to the other posts you can click below.


How the Vaccine Works Vaccine Ingredients Vaccine Efficacy Vaccine Necessity


Vaccine Safety

My goal for this section is to help people put the facts into real world perspective. All of the Covid vaccines are extremely safe. At this point they appear to be the cleanest, safest and most effective vaccines ever made. Getting a Covid vaccine is much safer than not getting one. Understanding how safe these vaccines are just requires a bit of perspective as you make your own assessment.

Q: Dr. Becky, did you choose to get the Covid vaccine?

A: You bet your tamales! I was offered the opportunity to get one of the early vaccine appointments in December, 2020 when the first shipments of Moderna and Pfizer vaccines rolled out. I jumped at the opportunity and have been fully vaccinated since mid January. I even considered signing up to be a test subject in March 2020 when they were recruiting test subjects for the Pfizer and Moderna vaccines. In the end, the time commitment they needed was too high, so I was unable to be a test subject, but I trust this technology enough that I certainly would have volunteered without hesitation had my schedule permitted.

Risk of harm from Vaccine vs Risk from Covid

infographic showing risk of getting covid vs risk of vaccine

Based on data available May 2021. (References 1-6). Please note that these numbers, in particular the percent of the population that has gotten Covid, died from Covid or has Post Covid syndrome, will continue to go up as the virus continues to spread.

Q: Are the Covid vaccines safe?

A: Short answer: YES. These vaccines are very, very safe, no matter what scale you use to measure safety. The list of possible adverse events is very short, and the number of each of these adverse events is less than 10 in 1 million. Compared to the risks associated with getting Covid (brain damage, kidney damage, lung damage, or suffocating to death), the risk of death or long term harm from the vaccine are essentially zero (less than 1 in 260 million). When you also factor in the risk of passing the virus on to others and causing this harm to them, or the damage done to our economy and society from the pandemic continuing for another several years, the risk of getting the vaccine is nearly non-existent.

Adverse Events: Allergic reactions

There have been a small handful of allergic reactions (most people had allergic reactions to previous vaccines) among the millions of people who have received the vaccine. This is not unique to the Covid vaccine. Most of the allergic reaction are with the mRNA vaccines. It is speculated that PEG used in the lipid nanoparticle is a likely trigger for those who have been previously sensitized. Right now about 10 people per million will have some level of allergic reaction to these vaccines, about 2 people per million will have an anaphylactic allergic reaction (usually within the first 15 minutes after the vaccine is given). There have been no deaths related to allergic reactions to these vaccines.

Adverse Events: Blood Clots

See Blood Clot question below.

Adverse Events: Flu-like symptoms

Some people experience a large immune response to these vaccines. This immune response often manifests as a fever, body aches and headache. The most common pattern is for this to begin about 12 hours after receiving the vaccine, lasting for 24 more hours. In a small percent of people, the immune response to the vaccine (fever, headache, body aches) lasts more than 24 hours. Not everyone has this response.

I would argue that this response is not an adverse event, but an ideal sign that your immune system is doing what it is supposed to do, and that it is doing it robustly. I generally do not recommend that people try to prevent or suppress these symptoms.

While the small number of adverse events are real, Covid is devastating and far more common. Even in people with mild disease, or no symptoms at all, there is a significant risk of developing Post Covid syndrome. Post Covid syndrome is a multi-system inflammatory illness that can damage lungs, kidneys, heart, blood vessels, brain, and more. We do not currently have reliable treatments for this. I have seen several cases of this in my practice, all in young people who had Covid but were virtually asymptomatic during the illness. I can tell you from firsthand experience, it is heartbreaking to watch.