In prior chapters, we touched on some of the unfounded claims that the anti-vaccine community makes about vaccines, medical providers who encourage immunization, pharmaceutical companies, and more. In the coming chapters, we will dispel the many myths about vaccines, but this chapter seeks to recognize and acknowledge the risks that do come with vaccinating. Contrary to what anti-vaccination supporters would assert, these risks are not being kept secret from patients to knowingly put them in harm’s way. Instead, they are readily available for people to read about, and they are typically much less common or worrisome than people opposed to vaccination would have us believe.

Most of you know this, but if there are any nonmedical people reading this book (and I hope that there are), I want to make it clear that no doctor or scientist has ever claimed that vaccines are 100% safe. As we read in chapter 5, vaccines undergo rigorous testing and retesting, both before and after licensure, to discover any safety issues present. Many vaccines never make it to market because they either didn’t achieve their goals or their risks were too great. But when a vaccine proves to be effective and safe enough for widespread use, like any other medical intervention, it still has possible risks. The staunch anti-vaccine folks are likely to take those last two sentences and twist them to make it sound as if doctors are knowingly harming people. So, let’s put it into context (Figure 7.1).

The risk of major adverse reactions (anaphylaxis, Guillain-Barré syndrome [GBS], etc) happening as a result of vaccination is exceedingly small—1 to 2 persons in a million. This pales in comparison to the risks of the diseases themselves. Measles, for instance, results in hospitalization for 1 in 4; encephalitis with the possibility of permanent brain damage for 1 in 1000; and death for 1 to 2 in 1000 patients infected. Meningitis infection results in death for 10 to 15 out of 100 patients infected, even with proper treatment. And what about some of the other things we do every day without thinking about their potential risks? Seat belts, if improperly fitted, have the potential to injure or kill people, but we don’t stop wearing seat belts.⁴ We know that the benefit of wearing a seat belt in the event of a car crash far outweighs the risks of the seat belt itself. Physicians recommend exercise to everyone to maintain overall health and to reduce the incidence of heart disease, stroke, diabetes, and other serious diseases; yet, every year people are seriously injured or die while exercising.⁵ Do we stop exercising because of what happens to those unfortunate few? No. We continue on because we know that the chance of serious injury is small compared with the greater benefit from getting regular exercise.

Now, should we do our best to make sure that these potential risks are minimized? For instance, should we ensure that our children’s seat belts are fitted properly? Yes. Should we check with our physicians to make sure we are healthy enough to engage in a vigorous exercise program? Absolutely! Should we choose the proper people to receive live-attenuated vaccines so that we don’t give an illness to someone whose immune system is compromised? Of course! Should we avoid giving a vaccine to someone during a serious illness or high fever? Most certainly! The point is, everything we do—in life and in medicine—has risks, and we do take measures to reduce those risks. The potential upside to pursuing preventative health measures is so great that we still do them despite the very minimal potential downside. We should think of vaccination in much the same way—the benefits far outweigh the risks.

That being said, we don’t want to downplay the possible adverse effects of vaccination just like we wouldn’t want to minimize the possible risks of any other intervention we do in medicine. We would never think of skipping a risk/benefit discussion with our patients who are headed into surgery, for example. We need to have a similar informed consent discussion when it comes to immunizations. However, I would argue that just handing someone a Vaccine Information Statement (VIS) prior to immunizing may not be adequate. How often do we thoroughly read the paperwork that we are given at the doctor’s office? Providing the VIS is required and important, but providing verbal informed consent will likely be more meaningful. This doesn’t mean that you have to have a long and detailed discussion of every possible risk and side effect of vaccines. Even a short discussion of the most common side effects following vaccination can set expectations so that patients and parents aren’t surprised or unnecessarily frightened if they experience an adverse reaction.

I suspect two reasons for why many people believe that the flu shot can make them sick. The first is our failure to adequately express the limitations of the vaccine in the first 2 weeks after administration (that it takes 2 weeks for the vaccine to become fully effective). The second is our failure to
caution our patient’s about the common and normal symptoms of a person’s immune system kicking into gear after vaccination (aches, fatigue, headache, low-grade fever, etc), an omission that leads people to attribute these symptoms to the flu shot making them “sick.” Setting up appropriate expectations is key, and patients will have greater confidence that we are not trying to “pull one over on them” if we are up front about possible risks. So, what are some common and not-so-common side effects or risks of vaccines? This chapter seeks to answer this question while giving a bit of perspective so that we can see these risks for what they are—mild or highly uncommon.