Measles. Mumps. Whooping cough. These diseases, which most parents of young children today have never even seen, let alone suffered through, are now popping up again in the U.S. So far this year, measles outbreaks have sickened more than 170 people; one died from measles-caused pneumonia. Mumps sidelined 1,151 people last year, more than twice as many as in 2013, including university students and NHL players. In 2012, there were more cases of whooping cough than in any year since 1955. “These diseases are still out there,” says Tina Tan, an infectious disease specialist at Lurie Children’s Hospital of Chicago. And it’s all too easy, she adds, for unvaccinated travelers to import infections from abroad.
The fortunate fact, experts say, is that most kids are protected. Government data show that fewer than 1 percent of young children receive no vaccines at all. In 2013, more than 90 percent of toddlers got the recommended doses of protection against measles, mumps and rubella; hepatitis B; polio; and chickenpox. But many families, in light of all the headlines in recent years about the tiny but vocal fraction of parents who object to vaccination, have questions even as they follow the recommended schedule. They wonder if all those vaccines are necessary, and how they can be sure the shots are safe.
It’s absolutely appropriate that parents seek the facts first, doctors say. “Parents should be skeptical of anything they put in their children’s bodies,” says Paul Offit, a professor of infectious diseases and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. But their questions about vaccines are answerable, he says. Here are some of the most common:
Are vaccines safe?
No drug is 100 percent risk-free. And parents should know what possible side effects to look for, as they would with any medication. Potential issues include a relatively common fever, for example, with the MMR vaccine for measles, mumps and rubella (1 in 10 cases) and, very rarely, a serious allergic reaction called anaphylaxis (1 in 1 million for all vaccinations). Certain kids, in certain specific circumstances, are advised not to get a shot — more about that later. But study after study has shown that vaccines are indeed very safe for the vast majority of people. In 2011, the Institute of Medicine, an independent federal advisory group, published the findings of an in-depth review of more than 1,000 studies looking for evidence of harm from eight vaccines lately of concern to parents, including the MMR, chickenpox and flu vaccines. The IOM’s conclusion? Most side effects are “very rare or very mild.”
And the benefits are considerable. Last year a report by the Centers for Disease Control and Prevention estimated that for babies born between 1994 and 2013, vaccination prevented about 322 million illnesses, 21 million hospitalizations and 732,000 premature deaths. The measles vaccine protects against other infectious diseases, too, scientists recently reported, likely because contracting the measles makes the immune system “forget” how to fight them off. “I tell parents vaccines are one of the greatest public health achievements and one of the safest and best protections you can give infants and children,” Tan says.
But what about links to autism? Or asthma and allergies?
The British study that garnered headlines 17 years ago when it hypothesized a link between autism and the MMR vaccine has been discredited and retracted. And the IOM report found no evidence of a link between the MMR and autism. This past April, the Journal of the American Medical Association published results of a very comprehensive study that analyzed the health insurance records of nearly 96,000 children and found that getting the vaccine “was not associated with an increased risk” of autism spectrum disorder at any age. Even kids whose older siblings had autism — considered a risk factor — did not develop the condition at higher rates after their vaccination.
The IOM report also found no evidence to support speculated links between the MMR or DTaP (diphtheria, tetanus and pertussis) vaccines and Type 1 diabetes. Nor did it find that the inactivated flu vaccine exacerbates asthma or causes Bell’s palsy, a facial nerve weakness.
So what kind of side effects are possible?
The most common side effects are pain at the injection site and fever, both of which mean that the immune system is responding as intended. Uncommonly, kids develop redness and swelling that affects the entire arm or leg for two or three days, says Neal Halsey, director of the Johns Hopkins Institute for Vaccine Safety, which studies and disseminates information on vaccine safety. That’s disconcerting but not dangerous, he says.
The IOM found evidence of 14 direct links between vaccines and adverse events, including fever-related seizures (scary but typically benign) and an exceedingly rare encephalitis that can develop in people with compromised immune systems after the MMR vaccine. The report also confirmed that six vaccines very rarely result in anaphylaxis. The chickenpox vaccine is linked to a chickenpox rash and can lead to secondary infections in people with weakened immune systems. And the injections themselves, no matter what’s in them, can cause fainting or temporary pain and loss of motion in the shoulder.
Ask your pediatrician about common side effects, particularly if your child has a history of immune system problems or serious allergies that you worry might make him or her vulnerable. And ask when you might expect to see them crop up. For example, the fever that may follow the MMR vaccine won’t show up for a week to 12 days, says Wendy Sue Swanson, a pediatrician and executive director of digital health at Seattle Children’s Hospital.
The key phase III studies of vaccines — the last studies before the vaccine is submitted for approval — will ferret out “common and relatively uncommon side effects,” Offit says. Still, since these trials involve thousands, rather than millions, of participants, they can’t always detect the very rare problems, he says. (Offit is the co-inventor of RotaTeq, a vaccine against the diarrhea-causing rotavirus given in three doses in infancy, but no longer has a financial interest in it.) If something seems off, don’t hesitate to call your doctor and run your concerns by her, Swanson says. “Instincts are important.”
If some kids shouldn’t be vaccinated, who are they?
Children who have a severe allergic reaction to one dose of a given vaccine, or who are allergic to any of its components, shouldn’t get that vaccine, according to the CDC. And children whose immune system is suppressed by serious disease or because they’re getting chemotherapy are also told to hold off on some shots. The CDC recommends that you and the doctor talk over the pros and cons of a given vaccine under certain other conditions — for example, if the child becomes limp and unresponsive or spikes a fever of at least 105 degrees within 48 hours of a previous DTaP dose.
What if a child has a bug at the time of your appointment? A moderate or severe illness is a reason to talk with the pediatrician about whether to give the shot on schedule or wait, the CDC says. But a mild illness, even with a fever, isn’t a reason to delay. Nor are vaccines typically postponed in underweight babies, with the exception of the hepatitis B vaccine under certain conditions. If your kid was irritable and fussy after one dose of a vaccine, that’s typical — and not a reason to push off the next dose, Swanson says.
How are the really rare problems found?
Because vaccines are recommended for most everyone, the government is serious about surveillance. Several public health systems are in place to catch very uncommon issues after vaccines are on the market. The government’s Vaccine Adverse Event Reporting System, known as VAERS, allows doctors and parents to enter a report of any ill effects they think might be related to vaccination. Those data don’t prove anything (and in fact are highly unreliable), but they can spark an investigation. In 1999, for example, the first vaccine approved to treat rotavirus was withdrawn from the market after reports of a type of bowel obstruction were submitted to the VAERS system and then investigated. The CDC found that the vaccine increased the chance of the problem by one or two cases per 10,000 babies vaccinated.
Another monitoring system, the Vaccine Safety Datalink, is a partnership between the CDC and nine large health systems. By analyzing electronic health records, the system can flag problems that seem to be occurring more often in kids who received a particular vaccine. Finally, the Clinical Immunization Safety Assessment Project, a collaboration between the CDC and a number of academic medical centers, conducts vaccine safety research and has investigators on hand to dig into reports of problems.
What’s the case for the vaccine schedule?
By the time they turn 3, kids are supposed to have been immunized against 14 different diseases (up from seven in the 1970s), with as many as 26 separate vaccinations and as many as five at one visit. Every year the Advisory Committee on Immunization Practices, a group of medical and public health experts, recommends which vaccines kids should get and at what age. The timeline is based on when the vaccine is most likely to be effective and safe, says Walter Orenstein, associate director of the Emory Vaccine Center in Atlanta. For example, the MMR vaccine provokes a poor immune response in young infants, so the first dose is recommended between 12 and 15 months.
This is the only schedule recommended by the American Academy of Pediatrics and other major medical groups. In a 2013 report on the subject, the IOM said it had found no reason to think the schedule is not safe.
While the number of vaccines is up, better technology now means there are far fewer bacterial or viral components across the whole schedule than in the 1970s or 1980s, Offit says. And there’s no evidence that a healthy child’s immune system is strained by multiple shots. Babies and kids are constantly exposed to antigens; the 15 or 16 antigens they’re getting in a single visit with multiple shots are insignificant by comparison, Tan says. “Not a single study confers an added benefit to risk reduction by spacing out vaccines,” Swanson says. “If you space them out, you prolong the amount of time children are vulnerable to disease, but it doesn’t reduce the risk of side effects.”
Still, parents commonly ask physicians to delay or space out vaccinations, according to a survey of pediatricians published in April in Pediatrics. While some doctors may vary their own timelines to accommodate parents, it’s important to know that alternative timing hasn’t been tested for safety and effectiveness, Tan says.
I survived chickenpox, so why can’t my kid skip that shot?
Yes, most adults alive today had chickenpox and came out with nothing more than a scar or two. But even that once-common disease can kill. Pre-vaccine, an average of 29 children between ages 1 and 9 died per year from chicken pox, mostly from infections of the blisters. In the period from 2002 to 2007, after the vaccine was instituted, six kids total died. The disease is also commonly more severe in adults, and going without a vaccination early on may put a child at risk later in life.
OK, but my infant surely isn’t at risk for hepatitis B. Can’t that shot wait?
Hepatitis B is an incurable, life-threatening liver infection. And infants are vulnerable; if they develop the disease, they have a 90 percent chance of becoming chronically infected, compared to 5 to 10 percent for healthy adults. Babies are vaccinated at birth because if the moms have the virus, they can pass it on to their babies. Pregnant women are supposed to be screened for the virus, but that doesn’t always happen. There are also rare cases of children acquiring hepatitis B from blood and bodily fluids. (It’s not just a disease spread by sexual contact and drug use.) So the goal is to minimize the window of susceptibility by immunizing as early as possible.
Excerpted from U.S. News’ “Best Hospitals 2016,” the definitive consumer guidebook to U.S. hospitals. Order your copy now.
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Parents’ Questions About Vaccines: Answered originally appeared on usnews.com
