COVID-19 vaccine safety
Risk of severe COVID-19 disease
A close friend of mine suffered a rare reaction from a vaccine, an experience that has since biased me. After considerable risk-to-benefit analysis for the new mRNA vaccine, today I received my first dose of the Pfizer-BioNTech COVID-19 vaccine. I wanted to share this analysis in hopes that it might help your vaccine decision.
This is not an endorsement for any company, simply my decision based on historical and currently available data.
COVID vaccine – my medical demographic
Every medical decision has risks and benefits, and they vary according to your personal history. Here is my relevant medical history:
- Age <65 years old, male.
- No significant medical conditions (i.e. no hypertension, no autoimmune disease).
- Not taking any immunosuppressive medications.
- No history of COVID-19 disease (my serology test was negative, meaning I had no antibodies to SARS-COV2).
My COVID-19 risk profile
- Severe COVID-19 disease: devastating but low (<1%).
- SARS-COV2 exposure: very high (as a practicing anesthesiologist).
- “Long haul” or “long tail” disease: difficult to estimate, likely <5%.
- Permanent lung scarring: difficult to estimate, likely <5%.
- Permanent damage to senses of taste/smell: devastating but low (<0.01%)
- Spreading COVID-19 to high-risk patients and loved ones: very high.
Personally, I am risk adverse because I cannot justify being ill and finding physician coverage for my work. I also fear becoming infected and spreading COVID-19 to high risk patients unknowingly.
COVID vaccine – the benefits
Available data shows 95% effectiveness in preventing COVID-19 disease. That’s 8 versus 162 cases from respective groups of ~18,000 participants:
|Group||# COVID-19 cases||Number of participants|
|COVID-19 vaccine||8 (1 severe COVID-19 case)||18,198|
|Placebo (saline injection)||162 (3 severe COVID-19 cases)||18325|
The doses are 21 days apart, and efficacy is ~52% between doses (starting ~12 days after the first dose). Practically, 95% efficacy is reached 7 days after the second dose.
Importantly, this primary study did not examine whether vaccination prevented asymptomatic infection. That means we are not sure if getting the vaccine prevents you from spreading infection to others. However, we are hopeful (and optimistic) that it will prevent spread to others.
Note generalizability of findings: 9% of total participants were Black or African American, 28% were Hispanic/Latino, 4% were Asian, and 0.5% American Indian/Alaska native.
COVID vaccine – adverse effects
Fever was reported in 11-16% of participants after the second dose. Severe allergic reactions have been ~1/100,000 from our observations as of the writing of this article. Soreness at the site of injection appears common.
Safety data was reported for approximately 14 weeks after the second dose.
My conclusion: none of these are concerning to me in my risk-to-benefit consideration.
COVID vaccine – my personal fear: Guillain-Barré syndrome
I want to be clear: given my particular demographic, fever, fatigue, muscle soreness, and small chance of (treatable) allergic reaction are NOT my concern. Risk of autism is beyond the scope of this article and I do not believe relevant to my risk-to-benefit analysis.
My greatest concern is about rare reactions that would be more severe than the “average” COVID-19 infection in a low-risk individual. That concern is Guillain-Barré syndrome – a rare but serious neurologic disease that can cause paralysis. Fortunately, most people recover, though some have a degree of weakness.
Guillain-Barré syndrome – anecdotal experience
I have a close friend that experienced Guillain-Barré syndrome after a vaccination. This clearly frightens and biases me. Thus, I wanted to rationalize my fear and share the safety data that helped inform my decision making.
Guillain-Barré syndrome – historical incidence after vaccines
Vaccine data from influenza and meningococcal vaccines show an incidence of Guillain-Barré syndrome of 1-2 per million. The concern first arose from association with the 1976 H1N1 inactivated influenza vaccine. Fortunately, it appears to be much less common since. Although none of these vaccines were mRNA-based, this is the only available data to-date.
Pfizer-BioNTech COVID-19 vaccine safety data was followed up to 14 weeks after the second dose. If Guillain-Barré syndrome were to be more common than 1 in ~20,000, it would likely have been observed during the trial. Not a single case has been recorded at the time of this writing.
COVID vaccine – conclusion
mRNA vaccines are newly “in the wild” and we do not have significant safety data beyond 14 weeks from second dose. Given the recorded safety to-date compared to the risk of severe or “long tail” disease, or possibly spreading virus to others, I chose the vaccine. This is my risk-to-benefit analysis in the context of my personal demographics, which is generalizable to much of the general population. I encourage readers to similarly consider their risk-to-benefit ratios and not be swayed by sensationalist media or “click-bait” headlines when it comes to their health.
Well wishes to everyone this holiday season. Stay safe!
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The information provided in this post in intended for general education. It is not medical advice. While I make every effort to provide the most up-to-date information, please note that new data is continuously becoming available and may change the conclusions I present here.
Polack, Fernando P., et al. “Safety and efficacy of the BNT162b2 mRNA covid-19 vaccine.” New England Journal of Medicine (2020).
Baxter B., et al. Lack of association of Guillain-Barré syndrome with vaccinations. Clin Infect Dis. 2013 Jul;57(2):197-204.
Lasky T, et al. The Guillain-Barré syndrome and the 1992-1993 and 1993-1994 influenza vaccines. N Engl J Med. 1998 Dec 17;339(25):1797-802.
Yih W, et al. No risk of Guillain-Barré syndrome found after meningococcal conjugate vaccination in two large cohort studies. Pharmacoepidemiol Drug Saf. 2012 Dec;21(12):1359-60.