Across America, parents are making the damning
decision to not vaccinate their children. Upon exploring a vaccine resistance
blog, claims for vaccine scandals, government propaganda, secret pathogen
exposure, and causative mechanisms for Autism appear to push people away from
the idea of getting vaccinated.[1] But what exactly is this
movement doing for the prevalence of virulent diseases in the American
population? According to the Council on Foreign Relations’ interactive map,
America has been experience clusters, outbreaks, and epidemics of
vaccine-preventable diseases since 2008.[2] Preventable diseases include: whooping cough,
mumps, and measles. In 2015, Texas experienced a widespread outbreak of measles
as the disease’s vaccination fell dangerously close to the percentage needed to
enact herd immunity (95%).[3] The Texas Department of
State Health Services reported over 45,000 children not complying with school
immunization laws because of non-medical reasons, a.k.a. personal opinions. 3 This is double the number of exemptions from
2010 and 19 times greater than in 2003, accompanying a growing anti-vaccination
movement (Figure 1, Figure 2). 3,[4] The CDC and VeryWell (a
user friendly health information site run by About, Inc.) demonstrate the
excessive number of outbreaks that have occurred over the past 5 years.[5], [6]
Berdnarczyk and colleagues retrieved data from the
National Immunization Survey-Teen (NIS-Teen) available through the CDC.[8] Data from 2008-2013was
normalized and analyzed the age at which individuals were vaccinated and the
effectiveness of the MMR vaccine.8 They
also took into account transplacental transfer of measles antibodies and
adolescent cancer treatment. In the sensitivity analysis, variation estimates
were calculated for vaccine coverage, vaccine effectiveness and duration of
maternal antibody protection, leading to a 0.98 multiplier for age-specific
vaccine coverage estimates to take into account decreases in immunization
coverage.8 Their results were compared
to the herd immunity threshold of 92% to provide a point of reference for
future studies. All analysis was based on 18 cumulative birth cohorts
consisting of 69,856,092 children and adolescents reported in the NIS-Teen. 8
As a result of data analysis, Berdnarczyk and colleagues
estimated 8,714,275 (12.5%) of the population in question to be susceptible to
measles.8 24.7% of children aged 3 years
or younger were found to be not immune while 9% of children and adolescents
aged 4-17 years were susceptible. Shockingly, the oldest population (13-17
years old) had over 1.5 million individuals not immune to measles even though
they had the longest amount of time to get vaccinated.8 Results appear to demonstrate that overall,
children and adolescents under the age of 17 are not reaching the heard
immunity threshold (87.5% of the population is immune) but within individual
age groups, except for children under three, the herd immunity threshold is
roughly met. Sensitivity adjustments determined 13.4% of children under the age
of 17 were susceptible to the disease with the variation estimates potentially
throwing some age groups under the desired threshold for immunity. 8 Maternal antibody protection through
placental transfer before birth brings this number down to 10.6% of the population
being susceptible. Figure 3 highlights the geographic regions where susceptible
children and adolescents are residing, acknowledging trends of vaccine
exemptions and areas for potential measles outbreaks (Figure 3). 8 Ultimately, the study concluded that although
immunity levels are within the herd immunity threshold, there are risks for
these levels to drop and certain age groups are more at risk than others.
This study utilized crude survey data to attempt an
estimation of all susceptible children and adolescents in America. Although,
based on the nature of the study, it is difficult to accept the results as
fact, it raises a terrifying point that approximately 10-13% of the American
youth aren’t immune to measles. Measles is a highly contagious virus that can
quickly cause outbreaks in confined areas such as schools, playgrounds and even
Disneyland. It disproportionately affects youth populations, who already have
poor hygiene skills and interact in close proximity to each other, making the
disease even more important to vaccinate against. Vaccine resistance movements
threaten herd immunity thresholds and lead to outbreaks of measles, as observed
in Texas in 2015. 3,4 It is important to recognize that members of
these movements aren’t “dumb” but are rather having difficulty interpreting
scientific data and conquering their initial impressions and paranoia
surrounding vaccines. Communication about the benefits of vaccines and that
several studies have debunked the theory that the MMR vaccine causes autism
needs to be established with the movement for the benefit of the general
public.[9] I believe that every one
is entitled to uphold their own beliefs, and in America, we as a people are
able to make our own decisions concerning health care. However, when evidence
indicates that a virus has potential to be eradicated or there is a preventive
measure to ensure my loved ones and myself won’t experience a serious disease, it
stands in the best interest that the vaccine is mandated for the population as
long as no serious side effects are observed. The anti-vaccination movement is
affecting how health-care workers are able to do their jobs and the way public
health policy is shaped. For now, schools are extending non-medical exceptions
for vaccinations, but only time will tell how the movement will affect public health
policy for the country.
[1] Vaccine Resistance Movement
website: http://vaccineresistancemovement.org/
The website highlights main reasons to avoid vaccines and other alternatives.
[2] Council
on Foreign Relations interactive Global Map of Vaccine-Preventable Outbreaks. http://www.cfr.org/interactives/GH_Vaccine_Map/#map
. The map addresses all the possible outbreaks of serious illnesses that could
have been avoided if the affected populations were vaccinated.
[3] Hotez,
Peter J. (2016) Texas and Its Measles Epidemics. PLoS Med. 13. 10.
[4] A policy brief by Rice University’s
Baker Institute for Public Policy that performs a case study on Texas
School-Entry Vaccinations. I highly recommend reading this report as a
compliment to this blog post. It can be found here: https://scholarship.rice.edu/bitstream/handle/1911/92690/BI-Brief-101316-STP_Vaccines.pdf?sequence=1&isAllowed=y
[5] The CDC’s breakdown of the
outbreaks of Measles across the United States: https://www.cdc.gov/measles/cases-outbreaks.html
[6]
VeryWell
provides easy to understand health information, tips and advice to the general
public. The site outlines all the outbreaks of Measles in 2015, including Texas
and Disneyland. https://www.verywell.com/measles-outbreaks-2633845
[7] Bednarczyk, R. A., Orenstein, W. A.
& Omer, S. B. (2016) Estimating the Number of Measles-Susceptible Children
and Adolescents in the United Staes Using data From the National Immunization
Survey-Teen (NIS-Teen). American Journal of Epidemiology. 184. 2.148-156.
[8] The CDC conducts the NIS-Teen to
estimate US vaccine coverage. Data is located on the CDC website: https://www.cdc.gov/vaccines/imz-managers/coverage/nis/teen/index.html
[9] Dales, L., Hammer, S. J. &
Smith, N. J. (2001) Time trends in Autism and in MMR Immunization Coverage in
California. Journal of the American Medical Association. 285. 9. 1183-1185.
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