7 Truths About Your Vaccine Concerns

…and other reasons some parents don’t want to vaccinate. Here’s the science behind the concerns.

Vaccine Truths Happy Baby with Colorful Bandaids Evan Kafka
Perhaps the most important health invention in history, vaccines are a victim of their success. “They’re so effective, they take diseases like measles away. But then we forget those diseases are dangerous,” says Kathryn Edwards, M.D., director of the Vanderbilt University Vaccine Research Program, in Nashville. Misinformation about vaccines also contributes to anxiety, and sorting truth from fiction isn’t always easy. The misconception that the measlesmumps-rubella (MMR) vaccine might cause autism has lingered in some parents’ minds for more than a decade, despite more than a dozen studies showing no link.

Vaccines do have risks, but our brain has a hard time putting risk in perspective, says Neal Halsey, M.D., a pediatrician and director of the Institute for Vaccine Safety at Johns Hopkins University, in Baltimore. People may fear flying more than driving because driving is common and familiar, but driving is far more dangerous. Vaccinating children to protect them against life-threatening diseases can cause mild, short-term side effects, such as redness and swelling at the injection site. But the most serious risks, such as severe allergic reactions, are far rarer than the diseases vaccines protect against. The Centers for Disease Control and Prevention (CDC) estimates the risk of serious allergic reaction from any vaccine is one in 1 million doses.

Even with minuscule risk, some parents may still be worried, and that makes sense. Here’s what you seldom hear from vaccine experts: There’s often an element of truth to parents’ concerns, even if they misunderstand some of the facts, Dr. Halsey says. That makes it even more frustrating if your doctor dismisses your fears or insists on vaccinating without answering all of your questions. In some cases, docs are refusing to treat kids whose parents don’t vaccinate, though the American Academy of Pediatrics (AAP) does not recommend that. So we’re giving you the lowdown on the most common fears.

The concern: “Vaccines may overwhelm my baby’s immune system.”

The Truth: Parents born in the 1970s and ’80s were vaccinated against eight diseases. A fully vaccinated 2-year-old today, on the other hand, is protected from 14 diseases. So while kids now get more shots—especially since each vaccine usually requires multiple doses—they’re protected against almost twice as many diseases. But it’s not the number of shots that matters; it’s what’s in them. Antigens are the viral or bacterial components of a vaccine that induce the immune system to make antibodies and fight future infections. The total number of antigens that children receive in vaccines today are a fraction of what kids used to receive, even with combination vaccines. 

The concern: “My child’s immune system is immature, so it’s safer to delay some vaccines or just get the most important ones.”

The Truth: This is the biggest misunderstanding, and it leads to susceptibility to diseases like measles. Delaying MMR by even three months increases the risk of febrile seizures. There’s no proof that spacing out vaccines is safer, and the vaccine schedule provides the greatest possible protection. 

The concern: “Vaccines contain toxins like mercury, aluminum, formaldehyde, and antifreeze.”

The Truth: Vaccines are mostly water with antigens, but they require additional ingredients to stabilize the solution or increase the vaccine’s effectiveness. Parents worry about mercury because some vaccines used to contain the preservative thimerosal, which breaks down into ethylmercury. Researchers now know that ethylmercury doesn’t accumulate in the body like methylmercury, the neurotoxin found in some fish. But thimerosal has been removed from all infant vaccines since 2001 “as a precaution,” Dr. Halsey says.

Vaccines do contain aluminum salts; these are used to enhance the body’s immune response, making the vaccine more effective. Although aluminum can cause greater redness or swelling at the injection site, the tiny amount of aluminum in vaccines—less than what kids get through breast milk, formula, or other sources—has no long-term effect and has been used in some vaccines since the 1930s. “It’s in soil, in our water, in the air. You’d have to leave the planet to avoid exposure,” says Ari Brown, M.D., author of Baby 411.

In some vaccines there may also be trace amounts of formaldehyde, used to prevent potential contamination, but that’s hundreds of times less than what we get from other sources, such as fruit and insulation material. Our body even naturally produces more formaldehyde than what’s in vaccines, Dr. Halsey says. Certain ingredients do pose some risks. Antibiotics, such as neomycin, used to prevent bacterial growth in some vaccines, and gelatin, used to prevent vaccine components from degrading, can cause extremely rare anaphylactic reactions (one or two per 1 million doses). Some vaccines contain trace amounts of egg protein, but studies have shown that kids with egg allergies can often still receive them. 

As for antifreeze, it is simply not in vaccines. Parents may confuse its chemical names—both ethylene glycol and propylene glycol—with the ingredients used in the vaccine manufacturing process (such as polyethylene glycol tert-octylphenyl ether, which is not harmful).

The concern: “There wouldn’t be ‘vaccine courts’ if vaccines weren’t dangerous.”

The Truth: As safe as vaccines are, unanticipated side effects do very rarely occur, says Dr. Halsey. The National Vaccine Injury Compensation Program provides money to parents to pay for medical and other costs in the unlikely situation where their child has a severe reaction. Why not just sue the pharmaceutical companies? That’s what happened in the 1980s, when dozens of companies making vaccines faced lawsuits. Most of those cases did not succeed, but the lawsuits took a toll. Several companies simply stopped making vaccines, which led to shortages, so Congress stepped in. 

Vaccine courts use a “no-fault system.” Parents don’t have to prove wrongdoing by the manufacturer, or that the vaccine caused the health problem. From 2006 to 2014, 1,876 claims were paid out (or one individual compensated for every million doses of vaccine distributed), according to the Health Resources and Services Administration. 

The concern: “Vaccines seem like a way for drug companies and doctors to make a lot of money.” 

The Truth: Pharmaceutical companies certainly profit from vaccines, but they’re hardly blockbuster drugs. These companies rarely receive funding from the federal government. Nearly all the money earmarked for vaccine research by the National Institutes of Health goes to universities. Pediatricians aren’t profiting either. “Most practices don’t make money from vaccines and often lose or break even on them,” says Nathan Boonstra, M.D., a pediatrician at Blank Children’s Hospital, in Des Moines. “Some find it too expensive to purchase, store, and administer vaccines, so they send patients to the county health department.”

The concern: “The side effects of some vaccines seem worse than the actual disease.”

The Truth: It takes 10 to 15 years and many studies for new vaccines to make it through all four phases of safety-and-effectiveness testing before they can get approved. Each new vaccine intended for children is first tested in adults, and then in children. The FDA scrutinizes the data, and the CDC, AAP, and American Academy of Family Physicians decide whether to recommend it. No agency or company will invest that money in a vaccine that causes worse health outcomes than it prevents, points out Dr. Halsey: “The diseases are all associated with serious complications that can lead to hospitalization or even death.” 

Even chicken pox, which many parents had themselves as kids, killed approximately 100 children a year before the varicella vaccine was introduced. It’s true that mild and moderate side effects—such as febrile seizure and high fever—are not unheard of, but serious side effects are far more rare. 

The concern: “Forcing me to vaccinate is a violation of my rights.”

The Truth: Each state’s vaccination laws are different; requirements for immunizations kick in when it’s time to attend day care, preschool, or public school. And for good reason: They protect the small percentage of children who may have a compromised immune system or for whom vaccines may not work. Every state allows exemptions if children have a medical reason for not vaccinating, such as having leukemia, and almost all states allow religious and/or personal-belief exemptions. “Each community has a right to maintain high levels of protection for those children who can’t be vaccinated,” Dr. Halsey says. The importance of that community protection is also known as herd immunity. “The overwhelming picture,” says Dr. Halsey, “is that vaccines are beneficial and keep children healthy. And that’s exactly what all of us want.”