A lot of my friends and family were concerned when I reported side effects from my first dose of the Pfizer vaccine. I appreciate your love and concern and I’m so sorry that I scared you! You make me feel cared for and loved!

I want to be clearer about this than I was last time: a sore arm, mild fever, headaches, body aches, and/or other side effects over a period of 24-48 hours are all healthy signs that your immune system is doing its job, without killing you in the process! Your immune system is reacting to something that is, fortunately, practically harmless, and this will prime your immune system to recognize and respond safely to something far more dangerous than a vaccine: the deadly coronavirus that causes COVID-19.

Let’s put this in perspective: The over half million people in the United States who have been killed by the coronavirus had violent, painful, horrifying immune responses to the coronavirus. Their immune systems were not prepared for the coronavirus. Your immune system responding to a vaccine is nothing at all like the awful suffering those who died went through.

The side effects you will experience from the vaccine will depend on your own individual immune system, body, and age. People who are older may experience less severe or no side effects at all in response to the coronavirus vaccine because their immune system no longer mounts the same level of attack on unrecognized agents. That’s what happens when we age, but you still have an immune system, it can still learn, so you will still be protected by the vaccine.

I’ve also seen concerns that the vaccines haven’t been properly tested. But they have! That’s the incredible benefit of living in the modern age: scientists and pandemic experts worried years ago about coronaviruses in particular causing a pandemic in humans, so they devoted many years and lots of research in preparation. They happened to be ready to go when the virus that causes COVID-19 arrived, and they were able to develop the vaccine not by taking short cuts but by building on the knowledge and technology they had already created in preparation for this moment. And don’t forget we now live in the Genomics Age. Scientists have been able to tap into this new frontier to assist in the characterization of this particular coronavirus and the creation of these remarkable new vaccines to combat it.

Vaccines, along with clean water and routine hand washing, are all relatively recent inventions in human history, and they’re the reason why infectious disease is no longer the number one killer of humans, like it was throughout most of our species’ history. Human lifespans have doubled or more since approximately 1900 because of these breakthroughs.

Another concern raised: what about the other ingredients in vaccines?

Years ago, tiny amounts of mercury used to be included in some vaccines. Before that, people used to slurp down spoonfuls of mercury for all sorts of uninformed snake oil reasons! When the dangers of mercury were later understood, mercury was removed from vaccines.

Later, a journal published the “research” of a fraudulent “doctor” who claimed vaccines cause autism in children. Other scientists immediately noticed problems with the study and no one was able to replicate his findings, but by then, the anti-vaccination movement had been born and it spread quickly, partly by concerned parents, partly by other fraudsters who made lots of money and gained a lot of fame based on this pseudoscience and fraud. I’ve watched in horror as this has unfolded in my lifetime, and it has resulted in a high level of public ignorance and the return of many horrible childhood diseases we thought we had control of.

So, is there still something in vaccines that could cause harm? Not likely. All the ingredients in vaccines are now regulated, well-characterized, understood, and known to be safe in the amounts they’re used.

A small number of people may have allergies to some of these ingredients, but if they do, they will probably already know it; these are commonly used ingredients. That’s why you’ll be asked if you have certain allergies before you are vaccinated. And if you do have a reaction because of a previously unknown allergy? The vaccination team will be ready to assist you immediately, because dealing calmly and quickly with allergic reactions is standard working procedure in medicine now.

I forget that not everyone has a background in medicine, science, and technology. I take it for granted. My continuing eduction in math, science, and, surprisingly, English and communications, helped me fill a skeptic’s toolbox with skills like Carl Sagan’s “skeptical thinking and an aptitude for wonder.” I hope I have helped allay your fears about the coronavirus vaccines. Please be safe, get vaccinated, and prepare for future booster shots. Despite our advanced modern medical reality compared to the past, politics, fear, and conspiracy theories have dangerously delayed our response to this coronavirus. That has given the virus time to mutate, and there are now thousands of variants, any one of which might evolve the ability to work around these current vaccines, if we don’t get everyone vaccinated as quickly as possible.

So how am I feeling today after my second dose of vaccine yesterday? My arm was only slightly sore last night and today I’m feeling fine! Maybe my slightly greater side effects during the first dose suggested my body was going to handle the second dose better. Or any of a number of possible reasons. Regardless, I’m happy to be vaccinated. And hopeful all my friends and loved ones will get vaccinated soon.