For pediatricians, few medical topics engender as much passion and controversy as vaccines. Parents are always encouraged to be as informed as possible about any medical topic, but be forewarned: there is a lot of misinformation out there about vaccines. Here are some of the common myths about vaccines:
- Myth: Vaccines are unsafe for pregnant women
Fact: Vaccines are safe and protective for pregnant women and their fetuses.
From the time they even think about getting pregnant, women are warned about the potential dangers of everything they put into their bodies. Because of this, vaccines are often described as dangerous to either the mother or her fetus. However, with a few exceptions, most vaccines are safe for pregnant women. In fact, two vaccines are recommended for all pregnant women: the influenza (or flu) vaccine and the tetanus-diphtheria-pertussis vaccine (Tdap).
A long history of vaccinations in pregnant women have shown that inactivated (or “dead”) vaccines are safe in pregnancy.1 In addition, vaccines given to pregnant women have been shown to protect the newborn infants of these women This is critical, because most vaccines can’t be given to newborns until they are several months old.
Some vaccines are contraindicated in pregnancy, such as the live virus vaccines varicella (chickenpox) and MMR (measles-mumps-rubella). There is a theoretical risk of the fetus getting the disease from the live virus vaccine. However, no cases of fetal damage or illness have been seen in those instances where a pregnant woman got these vaccines inadvertently. Still, it is recommended that women wait to become pregnant one month after getting these vaccines.1
- Myth: You can get the flu from the flu shot.
Fact: The flu shot is an inactivated virus vaccine, and you cannot get the flu from the flu shot.
Because the flu vaccine is one that pregnant women should get during flu season, this is an important myth to debunk. The flu shot is an inactivated virus vaccine, meaning the virus is essentially dead and not infectious. It is impossible to get the flu from the flu shot. In years past, the nasal flu vaccine contained a live virus, and it was theoretically possible to get the flu from that vaccine. However, that vaccine is not longer being used because it was not as effective as the flu shot.
Like with any vaccine, the flu shot may cause a reaction characterized by mild fever and muscle aches. This occurs in less than 1% of the people who are vaccinated. But some may interpret this as “the flu.”
A person does not acquire immunity to the flu until 1-2 weeks after the vaccination, so in the interim, a person could get exposed and contract a case of influenza. Because of the timing close to the flu shot, they may mistakenly assume the shot caused the illness.
- Myth: Vaccines cause autism
Fact: Dozens of studies have shown that vaccines decidedly do NOT cause autism.
This is the scariest myth out there, but also one that has been disproven multiple times. The problem began in 1998 when a doctor named Andrew Wakefield published a study in The Lancet of 12 children claiming that the MMR vaccine caused inflammatory bowel disease, letting dangerous proteins into the bloodstream and harming the brain, leading to autism. Later, The Lancet retracted the study after an investigation revealed some claims in the paper were false, and others were misrepresented by Wakefield.
Since then, over 25 articles have been published that have shown there is no connection between the MMR vaccine and autism. In many countries, studying hundreds of thousand of children, these studies show that there is no evidence connecting the vaccine to autism.
Another common misconception is that thimerosal, a preservative containing mercury that used to be in vaccines, was the cause of autism. But multiple studies have disproven that notion as well.2 Thimerosal was removed from nearly all childhood vaccines after a federal law was passed in 1997.
- Myth: Kids get too many vaccines now compared to past generations.
Fact: The antigenic load is actually LESS now than before.
Vaccines use antigens to induce a response in the immune system in the form of antibodies. Any material that is foreign to the body can do this, such as germs, foods, or medicines. Proteins are the principal ingredients that induce an immune response. Because the way we make vaccines today is so much better, the amount of protein (also known as the antigenic load) in vaccines today, even with an increased number of vaccines, is much smaller than the amount of 30 or even 50 years ago.
In 1960, in the three common childhood vaccines, there were about 3217 antigens. In 1980, in the three common childhood vaccines, there were about 3041 antigens. In 2000, in the six common childhood vaccines, there were about 123-126 antigens. A child’s body is exposed to thousands of antigens everyday. The amount in the vaccines is very small compared to what she is exposed to daily, and is actually less than the “good old days.”
- Myth: We don’t need to worry about those diseases anymore.
Fact: They are only a plane ride away.
Many people assume that the diseases that vaccines prevent are no longer a threat. Thanks to the success of vaccines, this is true for some diseases, like smallpox. However, even illness that are uncommon in the U.S., such as polio or measles, are still common in other parts of the world. And if enough people don’t vaccinate, these illnesses, which are just a plane ride away, can take hold and cause havoc.
No vaccination is 100% effective. To be truly effective, vaccines rely on something called herd immunity: the indirect protection from illness due to a significant percentage of the population being immune to the illness. So most people need to get immunized against a disease for everyone to benefit.
When enough people don’t get immunized against a certain illness, then herd immunity is lost, and introducing that illness into the population will spread to a lot of people, even some who have been vaccinated, because the vaccine is not100% effective.
This is what happened in Disneyland in 2014 when one person spread measles to over 145 people in the U.S. and a dozen more in Canada and Mexico.
In 1989, I was a pediatric intern in Chicago during the middle of the last measles outbreak in that city. I witnessed the horror of measles encephalitis, a brain infection, turn one delightful, playful young girl into a neurologically devastated child who would never walk or talk or laugh again. And another of my patients, a previously healthy young boy, died from measles. These diseases are still with us, and completely preventable.
- Myth: It’s safe to delay the vaccines until my child is older.
Fact: The diseases that vaccines prevent strike infants and toddlers, and delaying vaccines puts them at risk.
There is a reason that the schedule is set up the way it is: these diseases strike children at an early age. As a pediatric resident in the 1980s, I saw many children with meningitis caused by the bacteria Haemophilus influenza B (HIB). Many of them were affected for life with deafness or other disabilities, and some died. There was a vaccine against HIB, but it wasn’t given until 18 months old, too late for many children. After the introduction of a HIB vaccine that could be given as early as 2 months old, this disease has virtually disappeared in the U.S.
Delaying shots is, as one expert stated, like playing Russian Roulette with the baby, leaving her exposed when she is most vulnerable.2 There is no research to support delaying the vaccine schedule, so do your baby a favor and get her vaccinated on time.
As mentioned above, there is a lot of misinformation out there about vaccines. Pediatricians understand that parents have questions, and are sometimes scared of vaccines because of all the hype and erroneous messages they see. If you have questions about vaccines, be sure to bring them up with your health care provider so you can have an honest, informed discussion and make the best choice for you and your family.
1 Rasmussen SA, Watson AK, Kennedy ED, Broder KR, Jamieson DJ. Vaccines and pregnancy: past, present, and future. Semin Fetal Neonatal Med. 2014 Jun;19 (3):161-9.
2 Offit PA, Moser CA. Vaccines & your child : separating fact from fiction. New York: Columbia University Press; 2011.