Delaying vaccines is not only a waste of time, it could be dangerous to your kids. And no, foreigners aren't bringing most measles cases into the U.S.
Experts on measles vaccines say they're frustrated by the wide array of rumors being fed by websites, organized anti-vaccine groups, and the media. They debunked many of the myths at a seminar Monday organized by the Johns Hopkins school of public health.
Here are seven misconceptions they took on:
It's OK to delay vaccines and it lets your kid's immune system mature
No, it's not, says Dr. Neal Halsey, director of the Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health.
The Centers for Disease Control and Prevention recommends that babies get their first combined measles, mumps and rubella (MMR) vaccine at 12 months and a second dose at age 4 to 6, before starting pre-school or kindergarten. Not only is your child vulnerable to measles if you delay this, but older kids might be more likely to have frightening complications from the vaccine.
"People are delaying immunization for their children because they are concerned about this very small, precious 12-month-old," Halsey said. But about 5 percent of children develop what's known as febrile seizures when they get a fever for any reason. These seizures are almost always harmless, but they are scary.
And about one in 6 kids gets a fever after getting the first dose of MMR vaccine. This risk actually goes up in children older than 1, Halsey said. "So it is not safer to delay. It is safer to give the vaccine on schedule," he said.
And the immune system responds less effectively to vaccines as kids reach the teen years and beyond, so early vaccination is better, Halsey says.
It's also been shown that people who live in clusters with other vaccine-delaying parents or vaccine exempters have higher rates of vaccine-preventable disease such as pertussis or whooping cough, says Daniel Salmon, deputy director of the vaccine safety institute at Johns Hopkins.
"States that offer personal belief exemptions … have about 50 percent more pertussis than other states," Salmon said. "If you live in an exemption cluster, you are twice as likely to live in pertussis cluster."
Foreigners, especially illegal immigrants, are bringing measles to the US
It's true that measles was eliminated in the United States in 2000 and all outbreaks now begin with an imported case.
But last year, the worst year for measles in the U.S. since 1994, 635 out of 644 cases of measles were in U.S. citizens, says Dr. Diane Griffin of Johns Hopkins.
And out of these cases, 77 percent were unvaccinated people. What is mostly happening is that Americans who are not vaccinated are going to a country where measles is more common and bringing the virus back. Unless they live in a community where many people are not vaccinated, usually they don't infect very many other people, Griffin said.
"When measles happens anywhere in the world it can come here on a plane pretty quick," she said. And they aren't coming over land borders — measles has been eliminated in all of the Americas by very high vaccination rates. They're coming from Europe and Asia, as well as the Philippines.
"2011 that was the year that we were just bombarded from Europe, mostly from France," Griffin said.
More people die from the vaccine than from measles
Actually, measles kills more than 140,000 people a year globally, according to the World Health Organization. And WHO estimates that measles vaccines save 1 million lives a year.
In contrast, just 57 claims of deaths due to measles vaccines have been filed through the federal Vaccine Injury Compensation Program, a no-fault system set up to compensate people injured by vaccines. The program doesn't say how many of those claims were actually allowed.
"Here is one single vaccine that prevents more than a million deaths every year," Salmon said.
Existence of the Vaccine Injury Compensation Program proves vaccines are harmful
No one ever said vaccines are 100 percent safe. People can be allergic to a vaccine. Former California Rep. Henry Waxman helped write the legislation that led to the program's 1986 launch. He told the seminar it was set up because vaccine makers were dropping out of the business because of fear of pricey lawsuits, and public health officials feared the U.S. would suffer a shortage of vaccines.
"We looked at the problem and said what we needed to do was assure vaccine manufacturers that these rare, rare cases where they might be held to liability could be dealt with another way," Waxman told the seminar. The result was a no-fault system: If people could prove they suffered an injury that has been known to be caused by vaccine, they could be compensated without having to prove the vaccine caused the problem.
It's paid for by a tax on vaccines.
People who have been vaccinated can spread measles
This erroneous idea may be perpetuated by people who get measles mixed up with polio. Some polio vaccines are made using "live" viruses. These can revert to "wild" type and cause outbreaks, and now WHO recommends using a "killed" polio vaccine first to provide immunity and then boosting with the live one to prevent this spread.
Even though MMR vaccines are made using live viruses, they are weakened much more than the polio vaccine viruses.
"Measles live vaccine doesn't transmit easily at all," said Dr. Jane Seward of the CDC's Division of Viral Diseases. "I don't think there has ever been a secondary transmission," she added. "There is no evidence of any transmission of measles virus from a child to household contacts."
Vaccination is a political debate
It may look that way, with Republicans like New Jersey Governor Chris Christie and Kentucky Senator Rand Paul making comments about vaccination being a matter of liberty. But Waxman has seen vaccine questions raised from the left, also.
"This is not a partisan matter," he said. "There has been broad bipartisan support for immunizations. I think we have to recognize there are science deniers on the left as well as the right," he said.
Vaccines cause autism
This one's been debunked over and over but Halsey says it still comes up.
"The evidence is overwhelming," he said. The Institute of Medicine has investigated and repeatedly said it's not true. A special federal court, the U.S. Court of Federal Claims, ruled against three families in 2009 who claimed vaccines caused their children's autism, saying they had been "misled by physicians who are guilty … of gross medical misjudgment."