Why Worry About the Unvaccinated?
“If your child is vaccinated, why are you worried about them catching anything from my child?”
This is a common response from parents when it is suggested that a purposely unvaccinated child poses a threat to others.
One thing that many parents may not understand is that while vaccinations are highly effective, and greatly decrease the chance of contracting preventable diseases, no vaccine is 100% effective. According to CDC reports, “most routine childhood vaccines are effective for 85% to 95% of recipients. For reasons related to the individual, some will not develop immunity.”
This explains why, during an outbreak of a vaccine preventable disease, an unvaccinated child can increase the risk of disease for everyone that may be exposed, even if the people who have been vaccinated vastly outnumber those who have not. It is not uncommon for a small portion of the vaccinated population to be infected, However, that does not prove that vaccinations are not effective. To truly understand the risks, you need to know more than just the number of vaccinated vs. unvaccinated who have become infected. You have to appreciate the percentages that are involved. For instance, this example offered on the CDC website, explains this concept quite clearly:
“In a high school of 1,000 students, none has ever had measles. All but 5 of the students have had two doses of measles vaccine, and so are fully immunized. The entire student body is exposed to measles, and every susceptible student becomes infected. The 5 unvaccinated students will be infected, of course. But of the 995 who have been vaccinated, we would expect several not to respond to the vaccine. The efficacy rate for two doses of measles vaccine can be higher than 99%. In this class, 7 students do not respond, and they, too, become infected. Therefore 7 of 12, or about 58%, of the cases occur in students who have been fully vaccinated.
As you can see, this doesn’t prove the vaccine didn’t work – only that most of the children in the class had been vaccinated, so those who were vaccinated and did not respond outnumbered those who had not been vaccinated. Looking at it another way, 100% of the children who had not been vaccinated got measles, compared with less than 1% of those who had been vaccinated. Measles vaccine protected most of the class; if nobody in the class had been vaccinated, there would probably have been 1,000 cases of measles.”
When we consider this in relation to what is currently happening in our own communities today, we see why there is reason for the vaccinated to be concerned. For instance,
According to the Minnesota Department of Health, a recent measles outbreak was caused in part by former doctor and medical researcher Andrew Wakefield’s influential but fraudulent study suggesting a connection between child vaccination and autism. Due to his influence, many children in a Somali community there have chosen not to have their children immunized. Unfortunately, one of these unvaccinated children, was identified with measles after returning from a trip to Kenya. Currently, 15 cases have since been identified, five of which were too young to have received the vaccine, six were of age but were not vaccinated, one was vaccinated and three have unknown vaccine status, with a total of eight hospitalizations having been reported so far.
A small private school in Roanoke, VA, was closed last week due to an outbreak of pertussis (more commonly known as whooping cough). The school, which does not require students to be vaccinated, has reported 30 confirmed cases; 23 of which have been among the school’s 45 students, the others among staff. Dr. Molly O’Dell, director of the New River Health District, explained that the infected children were not vaccinated, while the adults infected were never revaccinated with a booster shot. Unfortunately, many adults do not realize that their immunity to pertussis wanes over time, and that a booster shot is suggested for continued immunity.
In Utah, a confirmed case of measles first appeared in an unvaccinated teen who returned from a trip to Europe. Since then, three other cases have been confirmed, none of which were vaccinated. Now, with six other suspected cases and a trail of possible exposure, it appears that the measles may have spread to four different schools. Gary Edwards, executive director of the Salt Lake Valley Health Department explained that “The vaccine is very effective against this illness,” which is why children who have not been adequately vaccinated will be temporarily excluded from school in order to contain any further spread of the disease.
In each of these instances, it is completely possible that some vaccinated children may become infected. However, it has been the unvaccinated children who have been shown to introduce the disease into these communiies. These modern day examples are just a few of the many instances that occur all over the country at any given time. These examples also serve to answer why a vaccinated person might be concerned about contracting a disease from the relatively small unvaccinated segment of the population.
Perhaps this video, by Shane Killion, brought to our attention by Gary Attarian on our Vaccinate Your Baby Facebook page, can further help to illustrate this phenomenon by providing a simulation of what is referred to as herd immunity. It can be effective in helping people understand how vaccine refusal can impact an entire community, even if that community is mostly vaccinated. The dots on the screen represent either vaccinated or unvaccinated people. The video then uses percentages to demonstrate the impact of a disease and the public consequences of a vaccine refuser.
Hopefully, as parents gain a better understanding of vaccinations, they will also come to understand why the vaccinated population might be concerned about vaccine refusal.
Unfortunately, public health is just that. Public. And one person’s vaccination decisions impacts the health of many others, whether they realize it or not.