As a business of the 21st century, we try to create an online presence as much as we create a physical presence.  We pepper our Twitter and Facebook feeds with fun marketing pictures, news blips, and resources as we see fit.  Of all our posts since opening, we received the most robust attention recently for a relatively simple post: “Why is the childhood immunization schedule the way it is?  Because, science.”

Vaccinations only work when a large percentage of the population takes part in the vaccinating process.  It’s called herd immunity.  Interestingly, though, vaccination rates have actually been decreasing since the 1990s.  What gives? A not-too-uncommon interaction I have with new parents goes something like this: 

PARENT: “What do you think about a delayed schedule?  Or not vaccinating?”  

ME: “How much time do you have?”

It’s a fair question, given the context in which we’re raising children today.  In order to organize my thoughts a little better and to attempt to reach out to a wider audience, I’ve taken a little time here to discuss vaccines, their history, why they’re still important, and why they’re not as scary as you’d first think. In putting this together, I’ve used primary sources such as the Centers for Disease Control (CDC) and the World Health Organization (WHO).  I’ve also used some secondary sources like the Children’s Hospital of Philadelphia’s phenomenal Vaccine Education Center and articles from the American Academy of Pediatrics (AAP) that help hesitant parents get the information they need. 

The bulk of this post originally appeared several years ago; I’m re-publishing it now in light of the continuing conversation around the development of a COVID-19 vaccine.  As we think to a future with a COVID-19 vaccine, it’s important to remind ourselves about the successes of vaccines in general.

Let’s get started.



Immunization is actually a very natural process.  Even before we’re born, many antibodies pass from mother to fetus.  Antibodies are also excreted in breastmilk to continue to protect children through the tenuous first years of their life. These forms of passive immunization are relatively short-lived; however, active immunization — personal exposure to a vaccine or illness — may last a lifetime.  

The idea for the first active immunization was discovered by happenstance and spot-on observations by Dr. Edward Jenner some 200 years ago in the UK.  He discovered that milkmaids who had previously been infected with cowpox seemed to be impervious to smallpox, an otherwise deadly disease. After intentionally infecting several (hopefully) willing subjects with cowpox and subsequently exposing them to smallpox, he had proof of his theory and the age of immunizations began.  

Fast forward into the 20th century, which saw the development of dozens of vaccines and the eventual eradication of smallpox from the planet.  In the whole history of science, this was a major victory.  We, as humans, finally could exercise a bit of control against the most microscopic (and deadly!) nuisances around.  

So, when we, as parents and as a society, start ruminating on the question as to whether or not to vaccinate, we must understand that we are in a place of great privilege from a historical perspective.  Jump down to the next paragraph: vaccine-preventable diseases are deadly and scary.  Finding vaccines for them was somewhat miraculous and gives us the hubris to walk about in our world full of deadly microorganisms with an immune system fully charged to protect us — but only if we’ve been vaccinated.



We have developed vaccines for a whole host of diseases with strange-sounding names: Rubella.  Diphtheria.  Measles.  Meningitis.  Rotavirus.  Polio.  Pertussis.  Mumps.  Most Americans are lucky enough that they’ve never contracted — nor seen — these illnesses.  And that may be why we don’t understand just how scary they can be when people are affected by them.  Paradoxically, the success of vaccines has been their own worst enemy.

Ultimately, each of these vaccine-preventable illnesses has the very real probability of causing serious, permanent harm.  Measles is highly contagious and was responsible for over 134,000 deaths worldwide in 2015.  Chicken pox can cause septic skin infections and even death.  The bacteria that causes tetanus is deadly and present in the soil — it doesn’t even take person-to-person contact to spread!  Polio leads to irreversible paralysis in 1/200 infections; our strides against this virus have made iron lungs a thing of the past.  That said, each of these illness is still present worldwide and could rise again — particularly with fewer people vaccinating.  Pertussus (a.k.a whooping cough) has seen a rise of late, and many scientists link it to declining vaccination rates.

(If you want more details about the different illnesses we prevent by giving childhood immunizations, feel free to browse through this slideshow from, an organization partially funded by the Center for Disease Control (CDC), that features pictures accompanying brief descriptions about the diseases. Warning: these are medical pictures; some may be more realistic than you’re used to. If you want a text-based review of vaccine-preventable diseases without the pictures, consult this site from the CDC.)



The vaccine schedule is rooted in science and determined by multiple factors, including the newborn’s ability to form an immune response, the risk of certain disease, waning maternal antibodies, etc.  There isn’t any high-quality, scientific evidence to support a delay in vaccinations or avoidance of vaccinations in the average, healthy child.  The American Academy of Pediatrics has a good Q&A about the vaccine schedule & why it is the way it is here — it’s worthwhile to read through it.  I tend to support a holistic, alternative-friendly approach to medicine (as you may have noticed), but there are some things were the evidence is pretty strong in support of Western medicine — and this is one area.  



The most common side effects from vaccines are pain, nausea, dizziness, and, for infants, tears, fussiness, rash, and potentially a slight fever.  We’ve had 60+ years of advanced vaccine research under our belt and information for the potential side effects of each vaccine can be found here.  There are a few serious reactions from vaccines, but these generally fall into the category of true allergies and anaphylaxis.  The CDC has a Vaccine Adverse Events Reporting System in place to track and follow up on any and all vaccine-related side effects in an effort to monitor the safety of vaccines and to create a standardized system of payouts to families affected by such events. A great article reviewing the payout system and the underlying rate of adverse effects can be found here

As a related aside, it’s really hard for us as humans to accurately judge risk.  Driving in a car is far riskier than flying in an airplane, but it’s the plane ride that induces anxiety.  Terrorism is fear-provoking, but millions (to billions) more people die annually from preventable causes like accidents, heart disease, lung cancer, etc.  The same thing with vaccines — we hear a story, and it inspires fear and confusion.  There’s also the problem of correlation and causation, two very different things. A colleague of mine, Dr. Ryan Neuhofel, put it pretty succinctly recently: “Many parents share stories of friends (or friends of friends) who believe their child to have a adverse event from a vaccine.  The truth is that vaccines are frequent in the first year of life, as are new (and sometimes scary) developments in a child’s life.  It’s important to remember that correlation is not causation.”  



Here are some frequent concerns about vaccines that are rooted in myth:

  • Vaccines cause autism.”  There is no evidence to suggest this, and the 1998 study claiming this was later found to be fraudulent.
  • Vaccines contain harmful preservatives.” No recommended childhood vaccines contain thimerosal (a nontoxic, mercury-derived component).  Other additives, like aluminum and formaldehyde, are included in negligible amounts that pale in comparison to what is naturally expressed in the body (Yes! Your body makes formaldehyde) or present in the environment.
  • Vaccines are a government and big Pharma conspiracy.”  Think what you will, but refer to all the other sections of this piece to see why vaccines are personally beneficial to you.
  • The childhood immunization series gives too many vaccines at once.” Scientific evidence shows that giving several vaccines at the same time has no negative effect on a child’s immune system.
  • The vaccine might give my child the disease.” Most vaccines are weakened and/or parts of the disease-causing bacteria or virus.  While a few vaccines are weakened, live pathogens, the rate of causing illness is quite low. 
  • Vaccines are 100% effective once you get them.”  Not quite — they’re close, but not perfect.  This is why vaccines become more effective on a population-level as more and more people get them.
  • What other concerns do you have?  Throw them my way, I’m always happy to discuss.



After all this fear-mongering and discussion, here’s the good news: you can protect yourself and your family!  Your local health department is the best resource for you to get up to date on your vaccines.  We don’t administer vaccines here at KCDPC (other than giving a teatanus shot if you need stitches here).   It’s a cost thing; the county health departments beat us on pricing and can bill insurance companies for the vaccines, so I just defer to them.  



If you, before reading this article, thought that vaccines were risky and are opting to delay vaccinations for your children (or leaning that way if you don’t yet have children), I may not have changed your mind with all the preceding arguments.  When we discuss controversial topics, we tend to process things in a way that solidifies our previously held beliefs.  Called “boomeranging” and discussed as early as the 1950s by psychologists, the phenomenon is seen across all spectrums of life (and is pretty entrenched in politics).  So if you’re a trail-blazer and like to find your own research, I recommend reviewing Children’s Hospital of Philadelphia’s piece on evaluating scientific research to help guide you on your quest for information. 


That said, each vaccine-preventable disease is potentially more deadly and harmful than the vaccine.  This is why it pains me that vaccines — and the debate surrounding them — have fallen into the category of controversy.  From a purely rational perspective, it’s difficult to refute the evidence supporting vaccination.  No controversy here, just facts.  So go out, do what you will, but please — get vaccinated first.


Allison Edwards, MD