Health Matters is a biweekly opinion column. The opinions expressed are solely those of the author.
Fevers. Chills. Headache. Arm pain.
All of these occurrences occurred at 1 am, after my second application of the Pfizer COVID-19 vaccine. However, it was the happiest fever, chills and headache I have ever had, because I knew that this short-lived post-vaccination illness would protect me from the serious COVID-19 illness.
Despite knowing about the side effects, I was surprised at how much they affected me and how prevalent it was among my co-workers. With several weeks of vaccination going on, it is important to ensure that everyone who receives the vaccine is perfectly aware of the side effects, in order to plan the next day accordingly and ease the fear that the vaccine will do more harm than good.
The chart below summarizes the two vaccines currently administered in Arlington. Both Pfizer and Moderna are considered “reactogenic”, as they stimulate a strong immune response with unpleasant but temporary side effects. Modern, despite being less effective (94.1% vs. 95% for Pfizer), it has 3x more vaccine than Pfizer (100 micrograms vs. 30 micrograms for Pfizer), which can contribute to more side effects seen.
Awareness about reactogenicity is particularly important because more Arlingtonians want the vaccine than anywhere in the U.S. and, as of 2/18/21, about 27,895 doses have been administered and 8,371 fully vaccinated, according to the Virginia Department of Health Vaccine Dashboard.
So why does your body react this way to the vaccine?
The immediate answer is to put the vaccine material in your arm. This immediate response is courtesy of the first branch of the immune system called innate immunity, which fights against anything it does not recognize. As your cells absorb the mRNA that encodes a version of the coronavirus spike protein, the innate immune system sets off alarms to recruit more immune cells into your arm, causing inflammation and pain, which results in more immune cell recruitment, causing the bigger picture fever and fatigue symptoms.
During this recruitment cascade, the second most specific branch of the immune system is activated, called adaptive immunity. The main participants in adaptive immunity are B cells, which are selective killers that create antibodies that bind to the spike protein, and T cells, which create a “wanted” cell poster of the infecting pathogen so that B cells know when and where attack.
Adaptive immunity is the adjusted part of the immune system that protects against COVID-19 after the second injection. When the second injection reintroduces the pathogen into the body, the adaptive immune system sends out a flood of cytokines, overriding the reactivated innate immune response, resulting in fever, pain and chills.
These side effects are a natural part of vaccination and, ultimately, demonstrate a functioning immune system – that doesn’t mean you have COVID-19. If you do not have these side effects, there is no need for an alarm, as many are successfully vaccinated with no side effects.
It is important to note that flu-like side effects are different from anaphylaxis or an allergic reaction, which is a much faster immune response that occurs in minutes. This known potential reaction led the CDC to recommend 15 minutes of observation time after vaccination for most people and 30 minutes for those with a history of anaphylaxis.
Scientists believe that the vaccines’ reactogenicity stems from the lipid nanoparticles used to package and protect mRNA when it enters cells. Lipid nanoparticles and mRNA are new approaches to vaccines, and Pfizer and Moderna are the first to use this nanotechnology. In fact, this technology can be used to further improve the effectiveness of influenza vaccines, which is underutilized (less than half of the U.S. acquired it last year) and performs poorly compared to the COVID vaccine (the vaccine against HIV). influenza reduces the risk of going to the doctor with influenza by 39% in 2019-2020). As lipid and mRNA technology advances, the hope is that reactogenicity will decrease.
What happens if you experience these symptoms after vaccination?
The first step is to rest and drink plenty of fluids. If your arm is sore, try applying a cold, damp towel to the area. The CDC recommended ibuprofen, aspirin, antihistamines and paracetamol for general pain and discomfort, but only after the shot. It is not known whether premedication before the vaccine affects the functioning of the vaccine.
Ultimately, although the side effects were surprisingly robust and prevalent in my health circle, they disappeared within 48 hours. I would not allow these side effects to prevent any medically liberated person from getting the vaccine. My goal is to make sure people are prepared for side effects and don’t panic if they do.
Dr. George C. Hwang, known to his patients as Dr. Chaucer, is an anesthesiologist who also helps run the Mental Peace Clinics in Arlington. He has written for various periodicals, textbooks and medical news agencies, and has lived in Arlington for 15 years.