What is Herd Immunity?

Herd Immunity

 Herd immunity is the protection of unvaccinated people by people who are vaccinated. It is a highly beneficial property of vaccines. Herd immunity protects people who don’t want to get vaccinated, people who do not develop immunity after receiving immunity, or people who cannot get vaccinated because of a medical condition, such as immunosuppressive conditions. In order for herd immunity to work, it is necessary to get a minimum percentage of the population vaccinated. This minimum percentage is different for every vaccine.  For instance, for the measles, approximately 90% of the population must be vaccinated and for pertussis this value is 95%. 

Lately, there has been an increase in vaccine preventable diseases.  Every day more and more people are deciding to forgo vaccinations, which is a reason why we are seeing measles and pertussis outbreaks more frequently. Some parents have declared that as long as everyone else's child is immunized, their child does not have to be. These parents assume that the rest of the herd will be immunized and thus protect their child from infections.

Some pediatricians have decided not to accept unvaccinated children; they are worried about the possibility of unvaccinated children sitting in their waiting room who might have a vaccine preventable disease, exposing patients who are medically unable to be vaccinated to possible infection.  During the first half of this year, there have been 131 cases of pertussis, including two sizable outbreaks with cases in 15 states and Washington, D.C. The vast majority of these cases could be linked to cases occurring outside of the United States. These have mainly been in individuals who were unimmunized, in most cases because of philosophical or religious objections. The most affected were schooled.

Educating the general population in an ever-changing world is a challenge.  Many people use non-creditable sources to get information about vaccines, while some people have no other choices since they are working and taking care of their children, and others simply don’t care to learn.  We created this website for you, parents, students and workers, to keep you updated on vaccines and their benefits.

- This article was written by Johanna Diaz

Reference

Brunell, Philip. "Herd Immunity - Defining the Herd?" Infectious Diseases in Children 21.10 (2008): 4-5. ABI/INFORM Complete; Hartford Courant; Hoover's Company Profiles; ProQuest Central; ProQuest Criminal Justice. Web. 8 Nov. 2012.

 Drennan, Vari. "Herd immunity." Primary Health Care Nov. 2011: 13. Health Reference Center Academic. Web. 7 Nov. 2012. <http://go.galegroup.com.libraryproxy.quinnipiac.edu/ps/i.do?id=GALE%7CA273197071&v=2.1&u=a13qu&it=r&p=HRCA&sw=w>

 Elbasha, Elamin H. "Prevalence of antibodies associated with herd immunity: a comment." Medical Decision Making 31.3 (2011): 511-513. Health Reference Center Academic. Web. 7 Nov. 2012.<http://go.galegroup.com.libraryproxy.quinnipiac.edu/ps/i.do?id=GALE%7CA264241357&v=2.1&u=a13qu&it=r&p=HRCA&sw=w>

O'Connor, Kath. "Herd Immunity." Australian Family Physician 36.9 (2007): 677-. ABI/INFORM Complete; Hartford Courant; Hoover's Company Profiles; ProQuest Central; ProQuest Criminal Justice. Web. 7 Nov. 2012.

Offit, Paul A. DEADLY CHOICES Basic (Adult Nonfiction) ISBN: 978-0-465-02149-9 Offit (Vaccinology and Pediatrics/Univ. of Pennsylvania; Autism's False Prophets: Bad Science, Risky Medicine.<http://go.galegroup.com.libraryproxy.quinnipiac.edu/ps/i.do?action=interpret&id=GALE%7CA256562472&v=2.1&u=a13qu&it=r&p=ITOF&sw=w&authCount=1>

"Vaccine Education Center ." Children's Hospital of Philadelphia . N.p., n.d. Web. 3 Dec. 2012. < http://www.chop.edu/export/download/pdfs/articles/vaccine-education-center/vaccine-baby.pdf >.