EXAMINING VACCINE HESITANCY FROM A PSYCHOLOGICAL PERSPECTIVE by Melissa Lopez A Thesis Submitted to the Faculty of The Wilkes Honors College in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Liberal Arts and Sciences with a Concentration in Psychology Wilkes Honors College of Florida Atlantic University Jupiter, Florida May 2019 EXAMINING VACCINE HESITANCY FROM A PSYCHOLOGICAL PERSPECTIVE by Melissa Lopez This thesis was prepared under the direction of the candidate’s thesis advisor, Dr. Laura Vernon, and has been approved by the members of her/his supervisory committee. It was submitted to the faculty of The Honors College and was accepted in partial fulfillment of the requirements for the degree of Bachelor of Science in Liberal Arts and Sciences. SUPERVISORY COMMITTEE: ____________________________ Dr. Laura Vernon ____________________________ Dr. Julie Earles ______________________________ Dean Ellen Goldey, Wilkes Honors College ____________ Date ii ACKNOWLEDGEMENTS I would like to thank Dr. Laura Vernon for being an extraordinary advisor. Your caring guidance and encouragement has helped me significantly throughout my college career. I would also like to thank Dr. Kevin Lanning and Dr. Julie Earles for being incredibly kind and helpful at times when I needed it the most. In addition, I would like to thank my parents, my sisters, my best friends, and my cat for being there by my side throughout this journey. You all have helped to give me the strength and support that I needed to get to this point in my academic career. Thank you endlessly. M.M.L. iii ABSTRACT Author: Melissa Lopez Title: Examining Vaccine Hesitancy from a Psychological Perspective Institution: Wilkes Honors College of Florida Atlantic University Thesis Advisor: Dr. Laura Vernon Degree: Bachelor of Science in Liberal Arts and Sciences Concentration: Psychology Year: 2019 According to the World Health Organization, one of the top ten threats to global health today is vaccine hesitancy. Reasons why people are hesitant towards vaccinating their children can fall into several categories, including being exposed to misinformation and conspiracy theories, being skeptical, and having altered perceptions of what the risks and benefits of receiving vaccines are. This paper will review psychological concepts that are likely to contribute to vaccine hesitancy and will make policy suggestions on the basis of findings from the psychological literature. It is essential to understand these issues in order to move forward and develop solutions to protect the health of those involved and those who could potentially be affected. It is equally as important to study possible strategies from a psychological perspective to ensure their effectiveness. iv TABLE OF CONTENTS I. Introduction……………………..……………………………….…………………..1 II. Vaccine Background Information………...…..…………………….……………….2 III. Vaccines from Past to Present……...……………………………………….……….4 IV. Reasons for Avoiding Vaccination.…………...……………………………….……8 A. Access…………………………………………………………………………8 B. Health Contraindications...……………………………………………………8 C. Religion and Personal Beliefs…………..……………………………………..9 V. The Problem of Non-vaccination…………………………………………………..10 A. Exposure to Misinformation………………………..………………………..11 B. Conspiracy Theories and Myths………………………..……………………14 C. Skepticism and Decision Making……………………………………………17 D. Perceptions of Risks and Benefits……………………………………………19 VI. Moving Forward….……………………………………………………………..…23 VII. Conclusion……………………………………………………..…………………..28 VIII. References………………………………………………………….……………....29 v Introduction Vaccines are products that are created to protect against infections that are caused by viruses or bacteria. Vaccines work by introducing an inactive virus to stimulate the body’s production of antibodies so that they are present in the body when a live virus presents itself. According to Kennedy, LaVail, Nowak, Basket, and Landry (2011), “Vaccines represent one of the greatest achievements of science and medicine in the battle against disease” (p.1151). Although vaccines play an essential role in preventing diseases and protecting the health of individuals, many people are hesitant about receiving them or allowing their children to receive them. Primary reasons why people are reluctant about vaccination stem from fears that vaccines are not safe, beliefs that vaccines do not work, and beliefs that vaccines are not necessary (WHO, 2019). To exemplify the issue of non-vaccination, there have been close to 500 outbreaks of measles in the United States in the first four months of 2019 despite being previously eliminated in the United States (CDC, 2019). An assessment of measles outbreaks from 2010 to 2015, shows that for approximately half of the cases the individual was qualified for vaccinations but did not receive them and of those cases most of them were unvaccinated for reasons that were not medically related (Phadke, Bednarczyk, Salmon, & Omer, 2016). To understand vaccine hesitancy, it is essential to first understand vaccines, how they work, and their history. 1 Vaccine Background Information The role of the vaccine is to imitate an infection in order to help the body build immunity against it. The three major kinds of white blood cells that play a role in building immunity include macrophages, T-lymphocytes, and B-lymphocytes. Macrophages digest invasive viruses and bacteria, leaving behind antigens which trigger the release of antibodies. B-lymphocytes generate antibodies that work to fight off any leftover antigens and T-lymphocytes attack infected cells. Some T-lymphocytes, also known as memory cells, are kept behind after the vaccine-induced infection goes away. T-lymphocytes along with B-lymphocytes will remember how to defend the body against the disease (CDC, 2018). According to the Centers for Disease Control and Prevention (CDC, 2018), there are five main types of vaccines: live, inactivated, toxoid, subunit, and conjugate. Live vaccines, such as the MMR and chickenpox vaccines, contain a weakened version of the virus or bacterium and typically only require one to two doses. Since these vaccines are stronger, people who have weakened immune systems cannot receive them. Inactivated vaccines include the flu, polio, and hepatitis A vaccines, which require multiple doses. Inactivated vaccines contain a bacterium or virus that has been killed (CDC, 2018). Unlike live and inactivated vaccines that fight viruses and bacteria, toxoid vaccines fight off toxins created by a bacterium instead of targeting the bacterium directly. The toxins in the vaccine are weakened and examples of toxoid vaccines include tetanus and diphtheria. Subunit vaccines such as the whooping cough vaccine, contain the most important parts of the virus or bacterium rather than the whole germ. Conjugate 2 vaccines help the body to form an immunity against viruses with polysaccharide coatings (CDC, 2018). The form of the germ that is used in a vaccine depends on how the germ acts in the body and the way in which the immune system responds to it. Vaccines are also composed of several other ingredients besides the antigen, each of which serve a purpose. According to the U.S. Department of Health and Human Services (HHS, 2017), vaccines are only composed of the ingredients that are essential in order to be “safe and effective”. These ingredients provide immunity, protect the life of the vaccine, and are used during the manufacturing process (HHS, 2017). The ingredients that provide immunity include antigens, the germ, and sometimes adjuvants, which are used to enhance the effect of immunity, such as aluminum. Preservatives and stabilizers are ingredients that protect the life of the vaccine. Preservatives protect the vaccine and stabilizers keep the active ingredients stable during shifts in the storage environment. An example of a preservative is thimerosal, an organic compound that contains mercury, but these are typically only used with multi-dose vials. Common stabilizers include sugar and gelatin (HHS, 2017). The ingredients that are used during the production of vaccines are often taken out once the vaccine is manufactured and only trace amounts are left at the end of the process. These ingredients include materials used to grow the antigen, germ killing agents, and antibiotics. Eggs are an example of an ingredient used in cell cultures to grow antigens and formaldehyde is sometimes used to kill germs (HHS, 2017). 3 Ingredients such as aluminum, thimerosal, and formaldehyde may sound dangerous but according to the HHS (2017) they are not considered dangerous. Aluminum is used in small amounts and has also been tested numerous times to ensure safety. Formaldehyde is mainly used during the process of creating the vaccine and the end result includes such a small amount that is not harmful to the body. When it comes to thimerosal, some might be afraid of mercury poisoning, but the HHS ensures that ethylmercury is the form that is used in vaccines whereas methylmercury is the form that is associated with poisoning (HHS, 2017). Vaccines from Past to Present The history of vaccines is considered to begin with Edward Jenner in the 1790s. Jenner, an English country doctor, was able to inoculate a young boy from smallpox (Stern & Markel, 2005). Over time, vaccines have become more popularized and are a common practice in the medical field. The World Health Organization’s Expanded Programme of Immunization (1974) and the Global Alliance for Vaccination and Immunization (2000) have contributed greatly