14 Getting to the point: importance of immunizations for public health

Stephanie F. James, PhD, MBA

Joshua P. Rickard, PharmD, MPH, BCACP, BCPS, CDCES

Lindsey Childs-Kean, PharmD, MPH, BCPS

Introduction

Immunizations have led to the eradication of some of the world’s most deadly diseases (such as smallpox) and to significant decreases in incidence of diseases such as rubella and measles. Total eradication is achieved when there is no circulating disease and no further measures to stop the disease are required. Despite significant gains toward the eradication of several infectious diseases, outbreaks may still occur, typically the result of an under-vaccinated population. In these populations, herd immunity (also known as “community immunity”), in which a sufficient proportion of the population is protected from a disease such that transmission among members is unlikely, is insufficient to protect unvaccinated members.^1,2,3 The Office of Disease Prevention and Health Promotion’s (ODPHP) has set several goals of reducing the number of vaccine-preventable diseases in the US. Pharmacists can play a large role in reaching such public health goals by understanding how immunizations confer protection, how diseases circulate in communities and counseling all patients to receive necessary immunizations as appropriate.⁴

In 2000, measles was declared eliminated in the US, although it was and still is endemic in other countries. However, since this time, the US has seen resurgence of this vaccine-preventable disease. Resurgence and resulting outbreaks are largely caused by introduction of the virus into a community from unvaccinated, overseas travelers, followed by disease transmission between unvaccinated individuals and those with an unknown vaccine history.^5,6 Acceptable or presumptive evidence of immunity includes written documentation of vaccination, laboratory evidence of immunity, laboratory confirmation of disease or in some cases, the age of an individual.⁷ As an example, in April 2017, a measles outbreak was identified in a group of US-born children of Somali descent.⁸ An investigation into the outbreak later revealed that this population had been subject to misinformation about vaccines and as a result had developed significant fears about autism. Amidst the outbreak, susceptible, unvaccinated persons believed to have been exposed to the virus were treated with post-exposure prophylaxis with a measles vaccine or immune globulin as per the Advisory Committee on Immunization Practices (ACIP) guidelines.⁸ However, the development of an adequate immune response to a vaccine requires several weeks.

From a scientific perspective, effective vaccination involves the development of a strong antibody response. The primary exposure to an antigen of interest (or vaccine) requires B-cells to recognize the antigen, become activated and begin to produce antibodies specific to this antigen as well as memory B-cells. This process can take between one to two weeks. Hence, if an unvaccinated individual is exposed to a pathogen, it is likely that pathology may occur during this development period. Although a certain amount of protection is afforded after initial vaccination, booster vaccinations are often required to further develop memory B-cells. Such memory B-cells can then produce antibodies to the antigen of interest within one to three days with no notable pathology.

The CDC has developed standards for adult immunization practices which may be found on the CDC website.⁹ It is well known that many individuals, including adults, are hesitant to receive immunizations. The reasons for adult vaccine hesitancy may be due to a variety of factors, such as complacency (not recognizing the risk of disease), lack of convenience or lack of confidence due to concerns regarding vaccine safety.¹⁰ However, several studies have suggested that a key factor in adult immunization is a strong recommendation from their provider.¹¹ It is important to understand that a key factor in adults becoming immunized is a strong recommendation from healthcare providers. For example, instead of asking a patient “Are you interested in being vaccinated for pneumococcal disease today?” say “I see it is time you are vaccinated for pneumococcal disease, which can help prevent pneumonia. If you give me a moment, I can prepare the vaccine for you and do it right now.” Pharmacists may also use the acronym SHARE to help them remember key counseling points:

• S: Share why the vaccine is recommended for that particular patient
• H: highlight positive benefits of the vaccine
• A: address patient questions in lay terms
• R: remind that vaccines not only protect the patient, but their loved ones around them
• E: explain the potential costs of disease.

Case

CC: “I’m worried the flu shot will hurt my unborn baby.”

Patient: TF is a 24-year-old female (62”, 58kg), 12 weeks pregnant with her second child. Her first child is a four-year-old male and was diagnosed with autism spectrum disorder (ASD) when he was three years old.

HPI: TF is at the pharmacy to pick up her prescription for prenatal vitamins. She tells you that her physician recommended that she receive an influenza vaccine. She is hesitant as her first son is on the autism spectrum, and she has heard conflicting stories about vaccines and autism. She would like more information on how vaccines work before agreeing to receive the vaccine.

PMH:

• First pregnancy resulted in live vaginal birth with no complications
• Mild heartburn symptoms during both pregnancies

FH:

• Both parents alive but with unknown health status
• No siblings
• One 4 year old son with ASD, otherwise healthy

SH:

• No alcohol, tobacco, or illicit drug consumption
• Lives with fiancée and son

Medications:

• Prenatal vitamin PO daily
• Calcium carbonate antacid PO as needed for heartburn

Allergies: none

Vitals:

• BP 120/70 mmHg
• HR 65 bpm

Case Questions

1. Why is vaccination after exposure to infection not as effective as prior vaccination?

2. Why is it important for pharmacists to be aware of diseases circulating within their community of practice?

3. How would you respond to a patient that states they do not need to vaccinate because they are healthy and can fight off most vaccine preventable diseases, such as influenza?

4. In talking with the patient, she states she stopped vaccinating after her son’s ASD diagnosis. How would you discuss this with her?

5. Describe how you could use the acronym SHARE to address this patient’s concerns for her unborn baby and today’s recommendation for an influenza vaccine.

6. What other vaccination(s) will the patient need to receive during her pregnancy?

Author Commentary

Immunizations are the best way to protect the general public from the spread of communicable disease. Some diseases such as influenza have several unique strains and hence yearly influenza vaccines are needed. Other vaccines prevent diseases caused by pathogens that do not change significantly over time. Without herd immunity, a population has enough potential disease vectors for a pathogen to circulate easily and infect not only the unvaccinated, but also those too young to receive vaccination or people that may be immune compromised.

Because many people are vaccine hesitant and do not vaccinate themselves or their children there has been a resurgence in some diseases, such as measles. According to the CDC, only 91.1% of children between ages 19-35 months old have received a measles vaccines, short of the 95% desired, and only 47% of children between six months and 17 years receive an influenza vaccine, leaving a significant portion of the population vulnerable to this disease. Vaccine hesitancy continues despite changes in vaccine formulations removing the preservative thimerosal, which was once blamed for adverse effects (although this has been shown to be untrue.) Vaccines are now available in prefilled syringes so preservatives are not included. Vaccines also contain significantly few antigens than in previous years, as vaccinologists have discovered the primary antigens necessary in a vaccine formulation to confer appropriate protection from disease. The use of fewer antigens has been complemented by improved vaccine adjuvants that promote reliable cell mediated and humoral responses to vaccines.

Patient Approaches and Opportunities

Pharmacists are well respected and easily accessible, particularly those involved in community pharmacy. Hence, they often function as a first resource for many people and parents to gain information regarding healthcare. Thus, it is critical that pharmacists are aware of how immunizations can protect a population, especially those that are unable to receive immunizations. Pharmacists should be aware of a patient’s concerns and potential hesitancy regarding vaccination and use the SHARE technique to help talk with patients. Such conversations between the pharmacist and patient may result in patients receiving appropriate referrals and care to further prevent spread of vaccine-preventable diseases.