Your second time may not be quite the same as your first.
Some people have reported experiencing more side effects when getting their second doses of the Moderna or Pfizer/BioNTech Covid-19 vaccine compared to when they got their first doses. For example, the COVID Symptom Study website states that “after effects are more common the second time around, with around one in five who received their second dose of the Pfizer vaccine logging at least one systemic effect.” Indeed, a December 31, 2020, publication in the New England Journal of Medicine had indicated that in the Phase 3 clinical trial of the Pfizer/BioNTech vaccine, side effects that involved more than just the injection site were reported “more often after dose 2 than dose 1.” A February 4, 2021, publication in the New England Journal of Medicine revealed a similar observation for the Moderna Covid-19 vaccine.
In this case, the “after effects” or side effects that they were referring to weren’t drastic ones such as growing an extra arm or suddenly liking the musical group Nickelback. Instead, they most commonly were “flu-like” symptoms like fatigue, headache, chills, and fever. I’ve covered such side effects previously for Forbes and described how they are typically the result of your immune system responding to what the vaccine generates in your body.
The first shot of the Covid-19 vaccine serves as the priming dose. The Moderna and Pfizer/BioNTech Covid-19 vaccines include mRNA, with the ”m” standing for “messenger” rather than whatever the “M” stands for in the song “MMMBop.” This mRNA serves as a blueprint for your cells to produce the spike proteins that normally stud the surface of the SARS-CoV2. Recall that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) looks somewhat like a spiky massage ball or the ball at the end of the mace used in BDSM. Here’s a 3D rendering of the virus in the background with the spike protein in the foreground:
The only available defenses then would be what’s called your innate immunity. In this case, innate doesn’t refer to where a sandwich has gone after singer Nate Reuss has eaten it. That would be “in Nate.” Instead, your innate immune system is the native set of defenses that your body already has against any type of potential invasion.
Your innate immunity is very general and not specific to any particular type of invader. It’s a bit like when you meet an unknown person for the first time. You may be ready to respond to standard, common issues that you deal with all the time, such as a person not maintaining any eye contact, being a bit standoffish, or asking you if you are related to a famous martial artist for the 2,971st time, not that anyone would be counting. However, you may not be prepared for a curve ball, something more unusual such as the person asking you a really unexpected question, being excessively nasty, throwing salad greens at you, or showing up wearing nothing but socks. These latter situations may leave you a bit stunned at first, requiring you to take some time to figure out how to deal with the situation. For example, you may not be immediately prepared with salad dressing when people launch salad greens at you. Similarly, your innate immune system may not be able to do whole lot when the Pfizer/BioNTech or Moderna Covid-19 vaccine exposes your body to the spike protein for the first time.
At the same time, your adaptive immune system, otherwise known as your acquired immune system, will not yet be ready with a response. Your adaptive immune system is the part of your immune system that offers a more specialized and tailored response against an invader. But this part of your immune system needs to be exposed to the invader first and then learn how to respond, a bit like what Gloria Gaynor was singing about in the song “I Will Survive.”
If you recall, the song begins with the line, “at first I was afraid, I was petrified.” Well, if your immune system has never seen the spike protein, your adaptive immune system probably doesn’t have a specific response to it. And the third and fourth lines of the song go, “but then I spent so many nights thinking how you did me wrong. And I grew strong. And I learned how to get along.” In the case of your adaptive immune system, “so many nights” may be about 10 to 14 days. This is the time it typically takes for your cells to generate the spike protein from the mRNA in the vaccines and your adaptive immune system to set up the proper defenses against the spike protein specifically. This way, 10 to 14 days after vaccination, should anything with the spike protein comes “back, from outer space,” or basically anywhere else, your adaptive immune system’s targeted defense system should be ready. This will allow your immune system to better say, “go on now, go, walk out the door. Just turn around now ’cause you’re not welcome anymore.”
That’s what your adaptive immune system can say when you get the second dose of the Covid-19 vaccine, the booster dose. This is supposed to remind your immune system about the spike protein by re-exposing your body to it. But if your adaptive immunity is already poised to act, more of a reaction may result. That’s why you may be more likely to get side effects following your second dose. Anything with a spike protein can’t just feel like dropping in and just expect your body to be free, so to speak.
So you may want to adjust your schedule so that you aren’t doing any crucial work around the time you are getting either dose of the Covid-19 vaccine, especially the second dose. Don’t plan on doing brain surgery, rocket science, financial deals with squirrels, or anything similar in the several days after you will be getting the vaccine. You may find yourself feeling a bit crummy and unable to concentrate. Plus, you know those squirrels, they can drive a hard bargain and offer terms that are nuts.