In the winter of 2015, when 147 cases of measles spread into seven states, plus Canada and Mexico, parents were unnerved, partly because the outbreak started at Disneyland,in California. But it could've been so much worse. If there were no measles vaccine, we'd have at least 4 million cases in the U.S. every year. Before the vaccine arrived in 1963, nearly everyone got the disease in childhood, and on average 440 kids died from it annually in the decade prior.
Fortunately, today between 80 and 90 percent of kids receive most vaccines. But in some regions in the U.S., growing numbers of parents are opting out. When that happens, they up the risk of outbreaks in their community. The most common reason parents skip vaccines? Safety concerns, despite overwhelming evidence that they're not dangerous. The most recent proof: an exhaustive 2013 report by the Institute of Medicine that found the U.S. childhood-immunization schedule is effective, with very few risks. (And we'll get to those.)
Perhaps the most important health invention in history, vaccines are a victim of their success.
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"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 measles-mumps-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 between the two.
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, fever, and rash. 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 estimates that the risk of a 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.
Parents born in the 1970s and '80s were vaccinated against eight diseases. A fully vaccinated 2-year-old today, on the other hand, can beat back 14 diseases. So while kids now get more shots—especially since each vaccine usually requires multiple doses—they're also 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 build up antibodies and fight future infections. The total antigens children receive in vaccines today are a fraction of what kids used to receive, even including combination vaccines.
"I'm an infectious-disease specialist, but I don't see infections in children after they've had all the routine vaccines at 2, 4, and 6 months of age, which would happen if their immune system were overloaded," says Mark H. Sawyer, M.D., professor of clinical pediatrics at the University of California San Diego School of Medicine and Rady Children's Hospital.
This is the biggest misunderstanding among parents today, says Dr. Halsey, and it leads to prolonged periods of susceptibility to diseases like measles. In the case of MMR, delaying the vaccine by even three months slightly increases the risk of febrile seizures.
There's no proof that spacing out vaccines is safer. What is known is that the recommended vaccine schedule is designed to provide the greatest possible protection. In fact, dozens of infectious-disease experts and epidemiologists from the CDC, universities, and hospitals across the U.S. closely examine decades of research before making their recommendations.
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—unlike methylmercury, the neurotoxin found in some fish. But thimerosal has been removed from all infant vaccines since 2001 "as a precaution," Dr. Halsey says. (Multidose flu vaccines still contain thimerosal for efficiency, but single doses without thimerosal are available.)
Vaccines do contain aluminum salts; these are used to enhance the body's immune response, stimulating greater antibody production and 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 our soil, in our water, in the air. You'd have to leave the planet to avoid exposure," says pediatrician and Parents advisor Ari Brown, M.D., of Austin, Texas.
Trace amounts of formaldehyde, used to inactivate potential contamination, may also be in some vaccines, but hundreds of times less than the amount of formaldehyde humans 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.
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Certain ingredients, however, do pose some risks. Antibiotics, such as neomycin, used to prevent bacterial growth in some vaccines, and gelatin, frequently used to prevent vaccine components from degrading over time, can cause extremely rare anaphylactic reactions (roughly once or twice per 1 million doses). Some vaccines may contain trace amounts of egg protein, but recent studies have shown that kids with egg allergies can often still receive them.
As for antifreeze, it is simply not in vaccines. Parents may be confusing 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 vast majority are 85 to 95 percent effective. The flu vaccine is particularly tricky, however. Each year, infectious-disease specialists from across the world meet to predict which strains are likely to circulate during the following flu season. The vaccine's effectiveness depends on the strains they pick—and sometimes they get it wrong. Last season's vaccine was only 23 percent effective at preventing flu; research shows that the vaccine can reduce the risk by about 50 to 60 percent when the right strain is selected.
So, yeah—the bottom line is that vaccines have meant far fewer deaths, hospitalizations, and disabilities than at any other time in history.
As safe as vaccines are, very rarely unanticipated side effects do occur, says Dr. Halsey. "And people should not have to bear the financial burden associated with that." The National Vaccine Injury Compensation Program (NVICP) provides money to parents so they can pay for the medical and other costs associated with an injury in the unlikely situation where their child experiences a severe vaccine reaction. (They also pay adults injured by vaccines.)
You may wonder, why not just sue the pharmaceutical companies? That's exactly what happened in the 1980s, when the dozen companies making vaccines faced lawsuits. Most of those cases did not succeed, however; winning required parents to show that a vaccine caused a health problem because it was defective. But the vaccines were not defective; they simply carried a known risk. Still, the lawsuits took a toll. Several companies simply stopped making vaccines, leading to shortages.
"Children were being left without vaccines, so Congress stepped in," says Dorit Reiss, a professor specializing in vaccine policy at the University of California Hastings College of Law. First it extended protection to manufacturers so they cannot be sued in court for vaccine injuries unless the claimant went through NVICP first, which allowed them to continue producing vaccines. Congress also made it easier for parents to receive compensation.
Vaccine courts operate on a "no-fault system." Parents don't have to prove wrongdoing on the manufacturer's part and are not required to prove beyond any reasonable doubt that the vaccine caused the health problem. In fact, some conditions are compensated even though science has not shown that vaccines definitely caused them. From 2006 to 2014, 1,876 claims were paid out. That amounts to one individual compensated for every 1 million doses of vaccine distributed, according to the Health Resources and Services Administration.
Pharmaceutical companies certainly see a profit from vaccines, but they're hardly blockbuster drugs. It's also reasonable for pharmaceutical companies to make money from their products, just as car-seat manufacturers earn profits from theirs. Contrary to popular belief, 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 even 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. "In fact, some find it too expensive to purchase, store, and administer vaccines, and have to send "Špatients to the county health department."
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It takes ten 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, then in children, and all new brands and formulations must go through the same process. The FDA then scrutinizes the data to ensure the vaccine does what the manufacturer says it does—and safely. From there, 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 problems 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. And it was a leading cause of necrotizing fasciitis, or flesh-eating bacterial infections. Dr. Halsey has heard parents say that good nutrition will help their kids fight these infections, but that's often not the case. Healthy children are at risk of serious complications and death from these diseases. For example, 80 percent of chicken-pox deaths occurred in otherwise healthy kids, he said.
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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. For instance, the most serious confirmed side effect of the rotavirus vaccine is intussusception, a bowel obstruction that may require surgery and occurs once in every 20,000 to 100,000 infants vaccinated.
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 or a rare immune disorder. What's more, all states allow religious and/or personal-belief exemptions, with varying requirements, except for California (starting July 2016), Mississippi, and West Virginia. Meanwhile, the exemption rates—and the disease rates—are higher in those states where it's easier for children to be granted an exemption.
"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, also called herd immunity, became especially clear during the Disneyland outbreak. Because measles is so contagious, it spreads quickly through communities with lower immunization coverage. Disneyland sits in the heart of Southern California, which has many of the lowest vaccination rates in the state, and most of the cases were among Californians in those communities.
"The overwhelming picture," summarizes Dr. Halsey, "is that vaccines are beneficial and keep children healthy. And that's exactly what all of us want—parents, health-care providers, and the people who make the vaccines."