The inconvenient truth of vaccine refusal

Claire McCarthy, MD

Faculty Editor, Harvard Health Publishing

Follow me at @drClaire

When I talk to parents who are hesitant about vaccines, what they most want to talk to me about are possible side effects of the vaccine. They worry about everything from fevers and soreness to additives to possible links to autism. They rarely worry about the diseases that vaccines prevent—and that’s what worries me most of all.

It is the inconvenient truth of vaccine refusal: when you don’t get vaccinated against an illness, you are more likely to catch it.

A study just released in the Journal of the American Medical Association (JAMA) makes this very clear. Researchers looked at information about recent measles and pertussis outbreaks. They found that unvaccinated people made up the majority of those who caught measles and a large proportion of those who caught pertussis (waning immunity from the pertussis vaccine plays a role in those outbreaks). Some weren’t old enough to be vaccinated—but of those who were old enough, most came from families who had chosen not to vaccinate.

We developed vaccines for a reason: to stop children from getting sick and dying. This was not a money-making stunt by drug companies, as some claim. Here in the United States, vaccines have done such a great job that we have literally forgotten about the ravages of measles, polio, pertussis, diphtheria, and the many other illnesses that we can now prevent.

They truly were ravages. Who even remembers diphtheria? Between 1936 and 1945, there were about 21,000 cases and 1,800 deaths a year of diphtheria. In those same years, paralytic polio affected 16,000 and killed 1,900 each year. And for measles and pertussis, the numbers are even higher. Every year 530,000 people caught measles and 440 people died from it; 200,000 caught pertussis and 4,000 died from it.

Four thousand died every year from pertussis. In 2014, that number was 13. We simply cannot ignore that vaccines are incredibly effective, and save thousands and thousands of lives.

It’s the scarcity of the illnesses that has made some parents comfortable with the decision not to vaccinate. If you are unlikely to run into anyone with measles or chickenpox, why take any chances with side effects?

There are two problems with that argument. First, as more people have chosen not to vaccinate, there have been more outbreaks. And when those who choose not to vaccinate live in the same communities, as a study out of Kaiser Permanente showed was the case in California, it can create the perfect environment for a vaccine-preventable germ to spread.

Second, we live in a global community. Travel is relatively easy, and lots of people do it. And while we may have done a great job eradicating vaccine-preventable diseases here in the U.S., they certainly haven’t been eradicated from the world. Diphtheria is still alive and well, affecting 50,000 people a year and killing half of them. There are 344,000 cases of measles—and 145,000 deaths from it. For pertussis, the numbers are even higher: 30-50 million cases, and 300,000 deaths.

People are often contagious before they even know they are sick. Someone could bring measles to a community without knowing it—and 90% of the unvaccinated people who are exposed to the measles virus will get sick (the virus can even hang out in a room for two hours after the person with measles leaves). Half of the babies who catch pertussis end up hospitalized—and of those who are hospitalized, three out of five have trouble breathing, and one in 100 die despite the best possible care.

We just can’t say that it’s safe to be unvaccinated. It’s not safe for the child whose parents choose not to vaccinate—and it’s really not safe for the infants or people with immune problems who cannot be vaccinated, who need vaccinated people around them to keep them well.

Vaccines are a medical treatment, and like any medical treatment, they can have risks and side effects. So much has been done, and is still being done, to make vaccines as safe as possible. It’s always important to ask questions and be careful in making decisions.

But when making those decisions, it’s crucial to think not just about the vaccine—but about the disease it can protect you from.


  1. Maria Jasmine Freeman

    Vaccines are really a dilemma. With high efficacy cost- effective vaccines like polio and Dtp, they are certainly to the benefit of the patient. For others, it might turn to the benefit of pharmaceutical companies. For measles, with all the debate about its association with autism, the vaccine saved many lives- especially in underdeveloped countries when earlier, measles was a killer of children.( a small story of my grandmother who lost five children, in series-consecutively, to measles, until she finally gained her sixth child- my father!). Though vitaminA decreases mortality to it, especially in winter, it does not exactly prevent it, and the benefit of using measles vaccine with a questionable risk of an unproven complication far outweighs the harm of high mortality due to the disease.
    Two more points remain to be mentioned. The trend to increasing vaccination-and sanitation in general, is definitely associated with an uprise of Asthma- which has become the threat to future generations. It is theorized that vaccination- Thimerosal included( previously used in Engerix) n over sanitation strategy cause a shift to more Th2 cells which drive the allergic response, instead of the Th1 helper cells that drive our normal immune response. Finally, vaccines are truly shifting the age of exposure to natural disease towards a more advanced age, n repeated boosters are aborting the opportunity for the individual to get exposed to natural infection to form his long- lasting immunity. In the latter framework I believe this can be ameliorated by not giving boosters and letting nature make this boost instead, to ensure it.
    Dr Hana Fayyad( Maria Jasmine Freeman)

  2. harold jitschak bueno de mesquita

    To compare tetanus or polio or diphtheria with measles or chickenpox or rota virus [i realise that the article do not mention all of them] is a real distortion of the truth.
    Even to compare polio and measles!!
    How dishonest to compare these? Or just a lack of experience?
    Measles is /was indeed a rather innocent disease,dependent on which part of the world you looked at and on what kind of populations.
    Africa with a possible severe vitamin A deficiency: yes,there it can be rampant.
    In the Western world or parts of the world where children are well nourished [indeed not specially the USA with often junk food]: measles was a benign ,virtually always minor disease which gave life long immunity.
    High doses of vitamin A [and possibly D] can change even problematic measles to a rapid healing disease.
    Mothers now vaccinated for measles may loose- as is well established -there immunity- at child bearing age and the newborn is then left totally unprotected which is the worst situation one can imagine!
    None of the “pushing organizations”may have realized this ,strange enough.
    Please, dear Harvard , I highly estimate your knowledge and positive publications ,but stay honest and don’t compare real dangers with trivial issues…………..this makes parents probably for a big part distrust doctors with their vaccination or other] advise.
    I am a physician and DO advise vaccination against the real still dangerous diseases but certainly not against varicella,rota and measles as a routine.

  3. Steve Allen

    In the future many people will regret having chosen to keep their heads in the sand and living in the dark ages. Once you are terminally ill from a vaccine preventable disease, possibly your only choice to end the suffering will be to commit suicide.

  4. Dr. George Bush

    This article is grossly uninformed and misleading. It lumps all vaccines together. You cannot make a rational, significant public health argument for many of the vaccines. Particularly for those that do not prevent infection or transmission such as the pertussis vaccine (shown in multiple studies to result in those immunized becoming asymptomatic carriers rather than it preventing transmission, also no discussion of the incredible amounts of vaccine failures), tetanus obviously is not contagious, varicella is obviously not a significant threat to life with a death rate of less than 1 in 2 million population prior to the vaccine, no discussion of the incredibly poor efficacy of the influenza vaccine, etc. I don’t have all day to write all the problems. Vaccines certainly have saved lives, but overselling them just makes Harvard look like another propaganda arm of the pharmaceutical industry. How about some real science out of this institution. I’m disappointed, albeit not surprised.

    • B

      Even the ipv has been demonstrated to not prevent contraction or transmission of polioviruses. So how it was credited with eradicating polio is beyond me…
      Especially when the vaccine was licensed and administered in 1955 and was the cause of deaths and over 40,000 cases of vaccine induced paralytic polio (which I actually wrote a paper on) (which was known as “The Cutter Incident.” To this day, the ipv still does not prevent contraction or transmission of polioviruses. Most people interpret “preventing disease” as “I’m going to be immune.”
      “Disease” medically means ” produces signs and symptoms.” So while vaccines (in cases) prevent “disease” (outward symptoms) they do not control the spread of viruses/bacteria. What I have the biggest issue with is how they are touted as “safe.” Someone doesn’t just look at a vaccine insert with lists of sometimes over 60+ side effects, life threatening and even death and say “oh yeah. That sounds safe.”
      Scarlet Fever had no vaccine yet it declined in line with everything else. What does she credit to that, because I’d love to know.

  5. erin dobrinen

    Thank you for the excellent and concise argument for vaccinating.

  6. Raesha Penwell

    There is NO way this article is speaking the whole truth.

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