Fear vs. Fact about Vaccine Safety

| Posted On May 08, 2014 | By:

group of healthy childrenI believe that one of my most important jobs as a pediatrician is to educate and counsel families on why vaccines are so important for their children. While the internet can be a wonderful source of information, it is also filled with websites which contain confusing, conflicting or incorrect information about vaccines, and I know many of the parents who see me in the office have been scared or convinced away from vaccinating their child based on what they have read online.

Below, I’ve tried to summarize some of the more common questions or concerns I hear from my patients about vaccines, and the medical advice and information I offer them to hopefully allay those concerns.

“I’m concerned about the number of vaccines that my child is getting in one dose or at one time. Can we divide the vaccine shot into parts or stretch out when we give my child certain vaccines over the course of a few weeks?”

First, some definitions may be needed. Some vaccines we give are called “combination vaccines” because they combine vaccines for different diseases into one single vaccine shot.  Examples of combination vaccines in current use are: DTaP (Diphtheria, Tetanus and Pertussis), trivalent IPV (three strains of inactivated polio vaccine), MMR (Measles, Mumps and Rubella), DTaP-Hib (Haemophilus influenza type B), and Pediarix™ and Pentacel® (which are both combinations of DTaP-IPV and Hib). Combination vaccines have been used in the United States since the 1940’s.

Moreover, we often give “simultaneous vaccines” at one visit, meaning we give a child more than one vaccine shot during the same visit, usually in separate arms or legs. An example of simultaneous vaccination might be administering DTaP in one arm and Hib in another arm during the same visit.

When I respond to these concerns, I often explain the scientific evidence that shows breaking up a combination vaccine or spacing out simultaneous vaccines is not safer for a child and may even be less effective. Vaccines today have a very low antigen load, meaning they contain a very small number of weakened and killed infectious agents, making them very safe.  But it also means that we need to combine antigens in a vaccine dose and combine vaccine doses so that a child’s immune system can recognize the antigen and initiate the immune response that’s needed to protect the child against the actual disease.

“I have heard about the bad things that can happen to my child from a vaccine shot, and I’m scared. What’s true and what’s not?”

I really spend a lot of time reassuring my parents that this fear is common and they are not alone. For example, despite the official retraction of the 1998 Lancet study that suggested a connection between the MMR vaccine and autism, as of 2010, 1 in 4 U.S. parents still believed that the vaccine could cause autism.

I like my parents to be prepared and educated about the vaccines we recommend for their children. As such, I inform parents in the prior visit of any vaccines we would recommend giving their child in the next visit.  In this way, they have time to research the vaccine(s) and be prepared to ask questions and voice any concerns.  Because of the amount of misinformation out there, I recommend parents visit the CDC’s website on vaccine safety which provides an overview of each vaccine and links to scientific articles and findings, and to the Vaccine Adverse Event Reporting System (VAERS) where you can report an incident and learn about any adverse reactions through what other families have reported.

Any vaccine can cause side effects – and we do not overlook these or take them lightly – but the side effects are usually mild, such as low-grade fever, and soreness, redness or swelling at the injection site. Rarely, a child may experience a severe allergic reaction or side effect such as a seizure. Although these rare side effects are a concern, vaccines are much safer than the diseases they prevent. We do not give vaccines to children who have known allergies to any of the vaccine components; moreover, if your child has a severe reaction to a particular vaccine, further doses of that vaccine won’t be given.

“Is it true that vaccines contain mercury? Isn’t that harmful to my child?”

None of the routine vaccines we give today contain the preservative thimerosal, a mercury-containing organic compound, and only some of the flu vaccine available contains a small amount. BUT, thimerosal contains a different form of mercury (called ethylmercury) than the kind that is found in fish, which is methylmercury.  Ethylmercury is broken down in the body and excreted much more rapidly than methylmercury. Therefore, ethylmercury is far less likely than methylmercury to build up in the body and cause harm.

We use other preservatives now because of the level of anxiety about mercury, but even if thimerosal was used today, your child would ingest more mercury from a single can of tuna fish than he or she would have received from all the vaccines we give a child in their first year of life.

“I don’t feel good about subjecting my child to painful shots if the disease doesn’t even exist anymore.”

I often say that vaccines are their own worst enemy, as vaccination of our population has been so effective that we have virtually wiped out diseases and no one talks about them anymore.

However, these diseases still do exist.

Recently, we have seen outbreaks in the United States of diseases we thought had been eradicated from our communities. There have been measles outbreaks both here in Boston and in New York City in February and March of this year.  In 2010, Pertussis, or whooping cough, a disease that can be extremely dangerous to infants, experienced its largest outbreak since 1947, due in large part to refusal of vaccination.  Polio is unfortunately coming back in parts of the Middle East due to the impact of war on the health delivery system.  Most recently, as displaced populations of Syrians flee their war-torn country and head north, fears are growing in many European countries that the disease could spread to their communities.

“If everyone else is vaccinated, why do I need to vaccinate my child?”

My answer to this question follows closely to my answer immediately above: the reality is that these diseases still do exist, there have been instances of community-level unavailability or refusal of vaccines, and the result has been disease outbreaks. This animated map illustrates it very clearly.  As long as there is one other person in close proximity to your child who is also unvaccinated, the risk for your child to contract a disease is present.

We are most concerned about newborns, as there is a period of time during which newborn babies cannot be vaccinated against certain diseases, making them particularly vulnerable to them. I discuss with families of newborns the “cocoon” of health that surrounds their baby and whether siblings, grandparents, parents, and other caregivers have been vaccinated and what the possible risks to the infant could be if someone has not been vaccinated.

“I had chicken pox as a child and now have a lifelong immunity to it. Why shouldn’t I just let nature run its course for my child versus a vaccine?”

While it is true that chicken pox is highly survivable (although scarring can occur), there are greater health risks associated with getting the disease. If your child gets chickenpox, he or she is at risk for getting shingles as an adult, as the virus that causes chickenpox stays dormant in the body and can reactivate as shingles.  The vaccine, which has an inactivated version of the varicella virus, protects from getting the chickenpox virus in the first place and therefore your child can never develop shingles.

Other diseases that we vaccine against, however, are often deadly, such as diphtheria, tetanus and measles, and many others lead to permanent disability (like polio) or future health problems.


If I can leave you with any parting advice, it is to please speak with your child’s pediatrician if you have heard or read anything about a vaccine that concerns you. Like you, we are strong advocates for your child and are here to help you make the most informed decisions you can about your child’s health and well-being.

Print Friendly, PDF & Email

About Dr. Jasmin Bhathena

Dr. Jasmin Bhathena joined Harvard Vanguard in 2009 as a pediatrician in our Peabody/Lynnfield practice. She has been practicing medicine since 1998 after completing her medical school education in Mumbai. She completed her internship and residency at Tufts Medical Center in Boston. Dr. Bhathena believes in a strong partnership between her and the families and children she cares for, and is very committed to developing long-standing, positive relationships built on trust and mutual respect.