The Doctor is In: Vaccines

My husband is a pediatrician. Once a week I share this space with him so that he can give you up-to-date and pertinent information about a variety of medical topics. If there are topics that you would like to see him address, please email me at queenofhaddock(at)gmail(dot)com.


***Disclaimer – this is my personal statement regarding vaccines and includes things that I tell my own patients/parents in visits to my office. This is not meant to be a substitute for a visit to or discussion with your pediatrician. For any questions regarding your child’s health you should of course discuss them with your pediatrician. This is meant only to provide information, which I hope you find helpful.***

So the most common thing folks have been asking about after my first two posts is some info about vaccines, with inquiries ranging from whether they link to autism, immune system stimulation, vaccine components, and the list goes on…this post could easily be ten to fifteen pages in length and barely scratch the surface, as there are countless books, journals, and other publications on the topic.  I’ll try to hit a few quick points on each of them without rambling too extensively.

I’m going to leave autism and vaccines to its own post, as I could not do it justice as a part of a larger post.  Entire volumes have been devoted to this topic, so I will only be hitting a few of the highlights. (SPOILER ALERT!! Vaccines DO NOT cause autism!)

Vaccines are probably the single most important advancement in public health and prevention of disease. Many people alive today truly do not appreciate the impact of vaccines, as they have never seen anyone with an active case of polio, diphtheria, even chicken pox.  I for one had chicken pox as a child, but in all of my time in medical school and since, I’ve seen one case.  I do know a few individuals who had polio in their lifetime.  One such individual was the pastor of the church we attended while I was in medical school, and he walks with a limp because of what polio did to him.  There once was a time when parents truly feared letting their children swim in the public pools for fear of the ravages of diseases which are now rarely found outside of the pages of a textbook.  Smallpox, which claimed the lives of some 300-500 million people in the 20th century (yes, 300 MILLION!) has been eradicated from the face of the planet, existing now only in deep freeze in two laboratories on two separate continents.  Even more so than antibiotics, vaccines have been hands down the most important advancement in health care and disease prevention.  The smallpox vaccine was in fact the first vaccine, developed in 1796 by Edward Jenner.

Regarding immune stimulation, many parents are concerned about “over stimulating” the immune system with the number of vaccines that children receive today vs. just the original smallpox vaccine.  To that concern there are several answers.  First, the immune system of children and adults alike is stimulated dozens of times every day with various allergens, viruses, bacteria, etc. that we encounter in everyday life.  It is in fact this stimulation that helps the immune system to develop properly. Viruses and bacteria have various proteins on their surfaces – those proteins are duplicated in the vaccine so that the immune system can see them, learn them, and recognize them on the virus or bacteria should it ever try to cause infection. Although it is true that the number of injections is higher than in the past, the total immune system stimulation is in fact less.  The small pox virus had over 200 unique proteins which were presented in the vaccine.  The entire combination of proteins presented to the immune system throughout the childhood vaccination schedule currently numbers about 153.  So even though there are more total injections, all of them combined represent only about 75% of the immune stimulation of the original single smallpox vaccine.  And as noted above, just a few weeks of normal living will present your immune system with more stimulation than the entire vaccination schedule.

As far as vaccine components are concerned, several different components are introduced during the production process.  Preservatives are used to prevent bacterial or fungal contamination.  The most infamous of those was thimerosal, which I will address in another post.  Briefly, it is now removed from the vast majority of vaccines, but was never a cause of any serious illness or condition.  The other currently used preservatives are very safe and are beneficial in preventing contamination of vaccines.  Prior to the use of preservatives contamination of vaccine vials by bacteria and fungus was not uncommon.

Another component of vaccines is adjuvants, which are included to enhance the immune response to the vaccines.  Currently aluminum salts are the only adjuvants used in the United States.  The amount of aluminum present in vaccines is comparable to that found in the environment, and in fact is comparable to that found in infant formula, foods, even breast milk.  Most infants will consume the same amount of aluminum in three days of breastfeeding as is found in most vaccines.

Additives are included in vaccines to keep them stable in varying temperatures, and to keep their components from adhering to sides of the vial. Types of additives include sugars, amino acids, and proteins.  The most common concern with these additives is the risk of an allergic reaction.  The most common cause of immediate reactions to these components is gelatin, and even it is rare (about 1 case per 2 million doses).  Simply being aware of any food allergies will prevent exposure in these cases – if you have food allergies to gelatin or eggs, make your doctor aware of them so that appropriate action and precautions may be taken. Also of concern for some parents are residuals of chemicals from the manufacturing process.  The first are inactivating agents which are used to eliminate bacterial toxins or the infectious capacity of viruses.  The most common agent of concern is formaldehyde.  While it is true that diluted formaldehyde is used during the manufacturing process, the vast majority is removed before the final product is shipped out.  The amount remaining is far less than the amount found naturally circulating in YOUR blood. That’s right – you have formaldehyde naturally circulating in your blood.  Formaldehyde is an essential component in human metabolism, and is required to synthesize amino acids and components of DNA.

Antibiotics are also used during the manufacturing process of vaccines to prevent contamination by bacteria.  The concern by parents in this is that there may be some residual antibiotic that may cause an allergic reaction.  First, the antibiotics that most commonly cause severe allergic reactions (penicillins, cephalosporins, sulfonamides) are not used in the manufacturing process. The only detectable antibiotic in vaccines is neomycin, and severe allergic reactions to the amount found in vaccines have never been clearly documented.  Rarely a delayed, less severe reaction may be seen, but this is not a reason to not be vaccinated.

Other residuals from the manufacturing process include egg proteins and yeast proteins.  Influenza and yellow fever vaccines are manufactured using eggs, and have enough egg protein to cause a severe reaction for those who are severely allergic to eggs.  Therefore, if you have an egg allergy, you should inform your physician prior to receiving influenza vaccine.  The only other vaccine that is produced using eggs is the MMR vaccine, but the amount of egg proteins is not enough to cause a severe reaction and even those with severe egg allergies may safely receive the MMR vaccine. As regards yeast, the hepatitis B vaccines are the only ones with residual yeast proteins.  To date no yeast-specific antibody has been detected in anyone who has had a reaction after hepatitis B vaccination, and so the risk of anaphylaxis after receiving hepatitis B vaccine is still theoretical.

The take home message is this: when all is said and done, vaccines are safe, extremely effective, and remain the greatest public health advancement to date.  There is NO reason to delay or refuse vaccines routinely. Often when we see an outbreak of vaccine-preventable disease, many of which can be fatal, it originates in a cluster of children who are denied vaccination.  So vaccinate your children with confidence, and give them the good health they deserve.

Sources cited:

Offit, Paul A. Autism’s False Prophet: Bad Science, Risky Medicine, and the Search for a Cure. New York: Columbia UP, 2008.

Offit, Paul A., and Rita K. Jew. “Addressing Parents’ Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives, or Residuals?” Pediatrics 112 (2003): 1394-401.

3 Responses to The Doctor is In: Vaccines
  1. Toni Michelle
    October 2, 2009 | 1:36 pm

    And this is why he is my pediatrician.. Wonderful education for us moms!! Thanks Dr Ivey! And Bridgette for letting him post on your site!

  2. Mandy Edwards
    October 2, 2009 | 3:53 pm

    Always love reading your column Marshall! Keep it up :o)

    p.s. this is really the only way I can get Ben to read anything medical!

  3. Leila
    October 6, 2009 | 11:20 am

    Great post Marshall! Well stated.