Incorporating Adult Immunization Service into Community

Author: Michael D. Hogue , PharmD

Behavioral Objectives

After completing this continuing education article, the pharmacist should be able to:

  1. Identify key steps necessary to begin offering immunization services in a community pharmacy practice.
  2. List regulatory requirements necessary for compliance before offering immunizations.
  3. Describe the incorporation of vaccine services into an existing dispensing work flow.
  4. Discuss vaccine reimbursement procedures.
  5. Identify resources for maintaining competence as an immunization provider.

The pharmacist's role as an important part of the public health system has long been underrecognized. At critical points in history, however, pharmacists have played an integral part in assisting with public health emergencies. For example, in the late 1800s and early 1900s, pharmacists were critically important in ensuring that diphtheria antitoxin was available during community outbreaks. In the early and mid 20th century, pharmacists often assumed a primary leadership role in their communities in the administration of oral polio vaccine.1

Beginning in 1996, a national campaign led by the American Pharmacists Association (APhA) sought to educate pharmacists in large numbers to serve as immunizers and vaccine advocates in their local communities, primarily in response to national health disparities in the immunization rates of adults against influenza and pneumococcal disease.1 Today, community pharmacies are recognized as routine outlets for receipt of annual flu vaccinations. Because of the unparalleled access community pharmacies provide to patients in need of lifesaving vaccines, many public health officials and others outside of the profession are beginning to advocate for an increasing role for pharmacists in providing adolescent and adult immunization services. Establishing a community pharmacybased immunization service provides for opportunities that are both professionally and financially rewarding, while at the same time providing a vital public health service. Pharmacists must consider many factors as they begin to implement immunization services into community practice.

Education and Training

Provision of immunization services is far more complex than simply giving shots. Vaccines are biologic products and carry the potential for allergic reaction and a slight risk of anaphylaxis. Additionally, timing and spacing of vaccines, as well as special storage and handling requirements, demand a more detailed decision-making process for vaccinating a particular patient. Because vaccines are the primary preventive agents for a host of potentially life-threatening illnesses, the Centers for Disease Control and Prevention (CDC) also makes national recommendations for the appropriate use of these products, which pharmacists should follow closely to ensure alignment with public health priorities and goals. Thus, before pharmacists begin offering immunizations in their practice, it is imperative that pharmacists ensure that they receive baseline training in vaccines, vaccine policy, and administration.

In the mid 1990s, schools and colleges of pharmacy first began incorporating vaccine-specific training into the doctor of pharmacy curriculum. The Accreditation Council for Pharmacy Education (ACPE), in its most recent standards revision (2007), has placed an increased emphasis on public health training of pharmacists.2 Specific to immunology, the additional guidance to schools on the science foundation of the doctor of pharmacy degree states that one key component should be "Immunology (including) (1) human immunity and immune response, (2) principles of antigen-antibody relationships, (3) molecular biology of immune response, and (4) genetic basis for antibody synthesis, development, function, and immunopathology."2 Thus, as time passes, an increasing number of pharmacists will enter practice with a baseline knowledge of immunology, which will reduce the need for intensive training of practitioners. For now, however, the majority of pharmacists in practice may not have received extensive training in the subject matter and will need to invest in appropriate training.

A variety of education and training programs in immunization delivery exist. As pharmacists evaluate their options for training in immunizations, it should be recognized that the CDC's National Immunization Program (NIP) training for public health officials in immunizations is considered the standard.3 Any training program being considered should at least provide the same degree or greater of topic coverage in the critical areas identified by NIP. Pharmacy continuing education (CE) providers offering immunization certificate training are listed at www.acpe.org. Costs associated with completing training will vary, depending on the program, but will likely require a time investment of between 16 and 24 contact hours and a financial investment of $250 or more if travel is necessary. While this may seem daunting, having adequate baseline training in vaccines is prudent to minimize potential liability. In addition, in some states, pharmacists are required to complete such training to be considered authorized to immunize by the respective state board of pharmacy. At the time of publication, only Maine, New Hampshire, New York, and West Virginia did not have laws or regulations specifically permitting pharmacists to administer vaccines (Figure); however, most of these states have bills in the legislative process or awaiting gubernatorial signature that would allow pharmacists immunization practice authority (Mitchel Rothholz, APhA, personal communication). Other states limit the types of vaccines that can be given by pharmacists or the ages of patients whom pharmacists can immunize. Pharmacists should consult their state board of pharmacy for more specific details.

Determine Community Immunization Needs

Before offering immunizations in the community pharmacy, pharmacists should assess the local needs of the adult population. The best way to make such an assessment is to contact the immunization nurse or coordinator with the county department of health. The department of health serves as a repository of statistics on the rates of vaccine-preventable illnesses, as well as immunization rates for reportable vaccines. Some states even have state-wide immunization registries, accessible by any immunization provider, to which pharmacists can document the immunizations administered in their practice, helping to ensure vaccination of only those in need. State and county departments of health would be interested in knowing of your status as an immunization provider, especially in preparation for pandemic influenza and other public health emergencies. Partnering with the department of health on existing vaccine-related outreach activities also will show your commitment to the health of the community. This collaboration is an essential component of any quality immunization program but is often overlooked by pharmacies in their haste to expand their business through vaccines.

Prepare for Storage and Handling

Vaccines, like most other biologic products, have very specific storage requirements. The CDC points out that, while it is easy to tell when many products have lost their purpose or concentration due to fluctuations in temperature, it is not easy to determine if vaccines have lost their efficacy, since they typically do not change consistency or color or cause an obvious change in response that can be easily recognized by the clinician.4 Vaccines that are exposed to extreme fluctuations in temperature or that are simply not stored appropriately will not afford their recipients the immunologic protection for which they were intended. The results of administering a vaccine stored improperly could be devastating if the recipient were exposed to the illness (or illnesses) the now-faulty vaccine was designed to prevent.

First and foremost, when beginning to offer vaccine services, make sure the refrigerator in which vaccines will be stored has a good seal. Secondly, determine if you will be offering frozen vaccines, such as the quadrivalent measles, mumps, rubella, and varicella vaccine; varicella vaccine; or zoster vaccine; If so, you also will need to ensure a properly sealing freezer compartment. Generally speaking, dormitory-size refrigerators are acceptable for refrigerated vaccines, but these units that contain small freezing compartments are not acceptable for frozen vaccines.5 The refrigeration and freezing units should have separate doors for entry, such as is the case with most full-size, top-and-bottom and side-by-side refrigerator/ freezers typically used in the home and in many pharmacies.

After ensuring that you have an appropriate refrigerator and freezer, the next step is to ensure that everyone in your pharmacy is keenly aware of the importance of vaccine storage. For example, when vaccines are ordered and arrive at your pharmacy, a designated staff person should immediately verify that the vaccine was maintained at an acceptable temperature throughout shipment (typically vaccines are shipped with temperature-monitoring devices) and then move the vaccine into the appropriate storage unit (refrigerator or freezer). Vaccine inventory should be rotated so that vaccines with the shortest expiration dates are utilized first. Additional principles for appropriate storage and handling of vaccines are listed in Table 61.

Comply with OSHA Regulations

The Occupational Safety and Health Administration (OSHA) of the US Department of Labor has implemented standards for the prevention of blood-borne pathogens in response to the Needlestick Safety and Prevention Act of 2001.7 All health care providers and facilities with potential exposure to blood-borne pathogens, due to the use of needles and lancets by the provider or in the facility, must comply with OSHA regulations. Community pharmacists implementing immunization services must ensure that they have met the OSHA blood-borne pathogen prevention standards before any vaccines are administered in their practice. In addition, according to OSHA, at least 24 states have adopted blood-borne pathogen standards as stringent as or more stringent than the federal standards. Pharmacists should consult their state department of health or to determine which standards apply in their state.

Among the pharmacist's considerations when achieving compliance with OSHA standards is that an OSHA exposure control plan must be in place in the facility and reviewed annually. All employees with potential blood-borne pathogen exposure should be familiar with the policies and procedures of this plan. A sample exposure control plan is available at www.osha.gov, and at least one customizable plan is available commercially through Stephan Foster, PharmD, faculty member at the University of Tennessee at sfoster@utmem.edu.

In addition to the need to establish an exposure control plan, pharmacists will need to involve all immunizers in the evaluation and selection of safer needle devices to determine which devices are optimal for the individuals administering vaccines in their pharmacy. Sharps containers must be used, and community pharmacists must make arrangements with a medical waste disposal service to ensure proper disposal. Alternatively, sharps containers packaged with prepaid mailers for return to an incineration facility for disposal are available through a variety of vendors, including Sharps Compliance Inc and GRP & Associates Inc, and may be more cost-effective for pharmacists who are not heavily engaged in immunization services.

In addition, pharmacists and anyone else in the pharmacy with potential for blood-borne pathogen exposure must be offered hepatitis B vaccination free of charge from the employer.7 Employees who choose not to be immunized against hepatitis B must sign a federally approved declination statement, which can be found at www.osha.gov .

Incorporate Vaccine Services into Your Work Flow

Many pharmacists are under the impression that offering vaccine-related services will disrupt their dispensing work flow. Stanley and colleagues of Ukrop's Pharmacies in Richmond, Va, report that, with practice, however, providing a vaccine takes about the same amount of time as filling a new prescription.8 Perhaps the reason behind the idea that vaccine services disrupt work flow is the image that pharmacists conduct only mass immunization events for flu shots. Pharmacists will find that, if they incorporate vaccines into their practice on a year-round basis, however, immunizing patients becomes a routine part of the pharmacy business. In fact, additional staffing resources are typically unnecessary except for the occasional 1- or 2-day mass flu immunization clinic in the fall. Mass immunization clinics do require extra planning and staffing to accommodate larger crowds and process vaccine requests separately from other prescription requests. In most cases, these mass immunization clinics can be set up in an area of the pharmacy separate from the dispensing area, so as to minimize work flow disruption.

For the pharmacist offering routine immunizations, such as tetanus-containing vaccines, pneumococcal vaccines, hepatitis vaccines, or shingles vaccines (zoster vaccine), it is recommended that these requests be processed just like any other prescription request. Place the vaccine request in the work flow, assigning a prescription number and label to each vaccine. By doing so, pharmacists have the added benefit of being able to review the patient's profile to determine if the possible presence of other drugs or conditions might warrant additional vaccines beyond the vaccine being requested by the patient. For example, while reviewing the prescription history of a patient requesting a flu shot, the pharmacist may discover the patient is taking digoxin, indicating heart failure. This, of course, would indicate that this patient might be a candidate for a pneumococcal vaccine. The pharmacist also might be aware that the patient has a newborn grandson, which would perhaps indicate the need for adult tetanus-diphtheria-acellular pertussis vaccine, if the patient's age is appropriate, to provide a ring of protection against pertussis around the newborn. Such a review strategy allows pharmacists the opportunity to provide comprehensive immunization services at a single patient visit.

Develop a Collaborative Practice Protocol

Because vaccines carry the federal legend, "Rx Only," as classified by the FDA, a prescriber must provide a valid order for these agents to be dispensed and administered. Pharmacists have at least 3 options for acquiring acceptable orders, depending on the laws of the state in which they practice. First, individual prescription orders can be written, transmitted electronically, or telephoned in by the prescriber in the same way other prescriptions are issued. The downside to this approach is that it limits the ability of the pharmacist to fully immunize patients in need of vaccines if the physician is unavailable (ie, on weekends or after office hours). The second option is to establish a protocol with each prescriber in the community to immunize his or her patients any time they present to the pharmacist for care and are in need of a vaccine(s). This option is preferred over the first option, but it does present logistic challenges in determining patients for whom the pharmacist can provide vaccines. This method also does not account for patients who may seek immunization services at the pharmacy but who do not have an established physician. Regardless, some states dictate that 1 of these 2 methods be utilized.

The last option is perhaps the best, primarily because it allows the pharmacist the greatest degree of freedom in decision making to determine (a) which patients need vaccines, and (b) which vaccines they need. This option is a collaborative practice protocol or establishment of standing orders for vaccines, signed by a single prescriber for any patient under the pharmacist's care. Under this arrangement, the prescriber is delegating his or her authority to the pharmacist to issue the prescription. The pharmacist must then use his or her professional judgment to determine the appropriateness of immunizing each particular patient. In the broadest sense, such collaborative practice protocols should allow the pharmacist to immunize any patient with any available vaccine within the limits of the state laws and regulations.

Prepare for Emergencies

The risk of severe allergic reaction such as anaphylaxis after vaccination with any vaccine is extremely small.9 Because the risk does exist, however, it is important for pharmacists to be prepared in case the event were to occur. Prudent pharmacists should have current cardiopulmonary resuscitation or basic cardiac life support certification before beginning immunization services. In addition, as a part of the collaborative practice protocol in place for vaccines, an emergency protocol that follows current procedures outlined by the American Heart Association and incorporates epinephrine administration should be in place. Additionally, staff at the pharmacy should be familiar with the emergency plan for anaphylaxis, practice it at least annually, and have it posted in the area where immunizations are administered. During an emergency requiring the administration of epinephrine, the pharmacist should appoint an individual in the pharmacy to record exact times of significant events in the emergency care of the patient. For example, the exact time the patient began having symptoms, the exact time the patient lost consciousness, and the exact time and amount of each epinephrine dose all should be recorded. A log can be very helpful to emergency response personnel once they arrive. Following any reaction believed to be related to vaccination, the immunizer should complete a Vaccine Adverse Event Reporting System (VAERS) form. Similar to a Medwatch form for adverse events related to other drugs, VAERS forms can be completed online at vaers.hhs.gov.

Regarding epinephrine, pharmacists are advised to stock at least 4 adult epinephrine (EpiPen) auto-injectors at all times when immunizations are to be given in the pharmacy. If EpiPen is unavailable, epinephrine ampules or vials in sufficient quantity for 2 patients to receive at least 2 doses each should be stocked. Caution: epinephrine typically has a very short expiration date. Stock should be rotated regularly. The dosing schedule for epinephrine should be clearly posted alongside the emergency plan in the immunization administration area.

Purchase Vaccine Wisely

The most common source for vaccines is the manufacturer. Drug wholesalers do stock commonly used vaccines, however, such as hepatitis B vaccine and tetanus-containing vaccine. In addition, some manufacturers distribute their vaccines through a select number of specialty wholesalers, which specialize in the distribution of biologic products. Especially during times of vaccine shortage, however, pharmacists need to be especially vigilant that all vaccine purchases are made from a reputable source that can ensure that the vaccine has been stored properly and provide a chain-of-ownership pedigree to demonstrate how the vaccine was acquired. Instances of counterfeit vaccine and improper storage of vaccine have made headlines in the past, and it is the pharmacists' responsibility to at least ensure that the supplier from whom they are purchasing is reputable. Because of counterfeiting and storage concerns, as long as pharmacists can meet minimum purchasing requirements, it is recommended that they purchase most vaccine direct from the manufacturer. Table 2 provides ordering information for major vaccine manufacturers.

How many doses of vaccine should a pharmacist purchase if one is just getting started in offering vaccine? Much of the answer lies in when the pharmacist is starting his or her immunization service. Many pharmacists have reported in unpublished survey responses to the APhA that they begin their first foray into immunizations with flu vaccine. While some obvious advantages exist to starting with flu shots, including low marketing investment and general acceptance of pharmacists as immunizers, the mass crowds created by flu shot campaigns can be very overwhelming to the novice immunizer. An alternative approach is to consider the purchase of 1 multidose vial of either pneumococcal or tetanus-containing vaccine and begin offering vaccine to regular prescription customers as identified as at-risk individuals when they present for their medications at any time during the year. This approach allows a minimal initial investment in vaccine and allows the pharmacist to build confidence as an immunizer at a more reasonable pace than may be experienced during flu season. If one does make the decision to start with influenza vaccine, it is recommended that an initial purchase of 250 to 500 doses is a reasonable firstseason investment.8 With such an investment, most pharmacists can offer the vaccine to high-risk patients during the course of their normal business activities, without having mass immunization clinic hours and without overwhelming potentially limited staff resources.

Ensure a Private, Comfortable Area for Administration

Especially in colder climates where patients may wear heavy garments, it is recommended the pharmacist identify a location within the pharmacy where patient privacy during the immunization process can be maintained. It is often necessary for patients to partially remove shirts and blouses so that adequate access to the deltoid region of the arm can be achieved. Patients appreciate having a private area in which to remove garments and be immunized. If you do not have a private consultation area available in your practice, consider purchasing 1 or 2 cubicle-style, 4-foot privacy partitions to place in an area near the pharmacy.

In addition, immunizations are best administered while patients are seated. The primary reasoning for this recommendation is so that the immunizer can control the fall of patients who might faint during or immediately after an immunization event. The pharmacist should invest in a chair with arms so as to help prevent falling. Additionally, for the comfort of both the patient and the immunizer, it is recommended that the immunizer be at approximately the same level as the patient when administering vaccines. For example, if the patient is seated, the immunizer should be seated. A small worktable in the immunization area for placement of vaccination supplies and a literature rack or information area for vaccine- preventable disease and public health messaging are also helpful. To comply with OSHA regulations, the sharps container must be situated in the administration area where patients (especially children) cannot easily reach into it.

Consider Vaccine Reimbursement Sources and Procedures

Vaccine reimbursement procedures are a bit more complex than traditional pharmaceutical product reimbursement. Pharmacists must first recognize that, when a vaccine is administered, 2 separate and distinct items are compensable: the vaccine itself and the service of administration of the vaccine. Because of this, many pharmacy benefit managers will not pay for vaccines, and in the event that they do, they are not likely to pay for the administration of the vaccine.

As of 2007, 2 procedures exist for Medicare reimbursement of vaccines and their administration. For influenza and pneumococcal vaccine, as well as hepatitis B vaccine for certain high-risk seniors, Medicare Part B provides full payment with no deductibles and no copayments through the state Part B carrier. Both pharmacists and pharmacies are eligible to bill the state Part B carrier as a mass immunization provider. Receiving Part B reimbursement includes 2 steps. First, the pharmacist or pharmacy must have a National Provider Identification (NPI) number. NPI numbers can be obtained through a relatively simple online application process at nppes.cms.hhs.gov/NPPES/StaticForward.do?forward=static.instructions.

The second step is becoming a Medicare Part B mass immunization provider. If the pharmacist is applying for this provider status, the appropriate application is Centers for Medicare and Medicaid Services (CMS) Form 855I. If the pharmacy is applying for mass immunization provider status, the appropriate application is CMS Form 855B. Both forms can be accessed at www.cms.hhs.gov/CMSForms/CMSForms/list.asp#TopOfPage. The appropriate form will have to be printed out and submitted in hard copy to the state Part B carrier. Please note that pharmacists who are durable medical equipment suppliers under Medicare Part B will still need to apply for mass immunization provider recognition separately, as the carriers for these 2 services are different. Both the vaccine and the administration fee are compensable under Medicare Part B using the appropriate Current Procedural Terminology, International Classification of Diseases, 9th ed, and/or Healthcare Common Procedure Coding System codes. Part B carriers prefer online submission of claims, and, if billed online, clean claim payment can generally be expected within 15 days.

Medicare Part D allows for compensation of all non?Part B vaccines (ie, anything except influenza, pneumococcal, and hepatitis B) through its contracted prescription drug plan (PDP) sponsors. CMS guidance details that, through 2007, Part D vaccines (such as zoster vaccine) are covered through the PDP, and the administration fee is covered separately by Medicare Part B. In 2008, both the administration fee and the vaccines will be covered under Part D. At the time of publication, the exact procedures for billing of vaccines and the administration fees for 2008 were unclear. Pharmacists should consult with the applicable PDP or Medicare Advantage-PDP for detailed billing instructions.

Private insurance companies vary widely in their coverage of vaccines. For self-insured or employer-insured individuals, the major medical benefit is most likely the portion of the insurance coverage that will cover vaccines and their administration. Pediatric vaccines are generally covered through age 18 years or as recommended on the pediatric immunization schedule of the CDC. Adult vaccine coverage is very sporadic. Because most vaccines cost a great deal, it is strongly advised that pharmacists verify insurance coverage before administering the vaccine.

State Medicaid programs, like private insurers, vary widely in their coverage of vaccines, particularly those used in adults. Some state Medicaid programs will reimburse pharmacists for the vaccine and its administration, while others will not. Pharmacists should check with the provider services division of their state's Medicaid program for more details.

Pharmacists will often find that many patients may pay out of pocket for certain vaccines. For example, non?Medicare-covered adults may be accustomed to paying cash for their flu shots. Because tetanus-containing vaccines are recommended only every 10 years, many patients may be willing to pay cash for the immunization service. Vaccines used primarily for international travel are typically not covered by insurance, and patients also expect to pay for these vaccines. Regardless of the situation, pharmacists should ensure that a receipt is provided to the patient for any fees paid for immunization services so that patients have the opportunity to seek insurance reimbursement on their own, seek medical savings account reimbursement through employer cafeteria plans, or write off the expense on their income tax.

Establish a System for Staying Up-to-date

Once a pharmacist establishes himself or herself as an immunizer, the work is not finished. Maintaining competency in vaccines is a continuous process. The Advisory Committee on Immunization Practices of the CDC meets at least quarterly and makes recommendations for changes to national immunization policy at practically every meeting. The harmonized pediatric and adolescent immunization schedule is published each year in January. The adult immunization schedule is revised each year in October. In addition, vaccine manufacturers regularly release important information regarding new vaccines, vaccine shortages, and vaccine adverse-event reports. The field of vaccines is constantly changing, and pharmacists must regularly review literature so as to ensure that they are optimally caring for their patients.

The Immunization Action Coalition (IAC), located in Minneapolis, Minn, is nationally recognized as the leader in the private industry for providing unbiased vaccine and vaccine-preventable disease information and provider resources. A wealth of practice management resources is available via the IAC Web site at www.immunize.org; many resources are available at little or no charge.

The APhA offers a list service for immunizing pharmacists. The list service contains much of the same information found through other immunization list services, with additional information specific to pharmacy practice included as well. The service is offered by APhA, free of charge, by sending an e-mail to subscribe to mrothholz@aphanet.org.

A variety of quality CE programs are available on vaccines and vaccine-preventable diseases. The CDC now offers ACPE credit for pharmacists who complete the learning exercises associated with specific issues of Morbidity and Mortality Weekly Report. All CE programs offered as Webcasts via the NIP Web site ( www.cdc.gov/vaccines ) also are ACPE-accredited. Because the CDC is the agency responsible for issuing vaccine policy in the United States, the pharmacist can rest assured that the content available through the CDC is the most up-to-date available.

At a minimum, pharmacists should complete an annual update on changes in immunizations and immunization policy. The CDC offers such an update through its Web site. The APhA, the American Society of Health-System Pharmacists, the American Society of Consultant Pharmacists, and the National Community Pharmacists Association also offer similar updates, which include pharmacy practice implications, at their annual meetings and via their respective Web sites. Table 3 provides a partial listing of resources for immunizing pharmacists.


Making the decision to begin immunization services should not be taken lightly. Adequate preparation is necessary to ensure a successful practice. The opportunity to be a part of a major public health initiative such as immunizations is extraordinary and allows pharmacists to prove to their local communities a strong commitment to the health and welfare of the community. Vaccination service can be both profitable and professionally satisfying, and pharmacists are encouraged to give it a shot!

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  1. Hogue MD, Grabenstein JD, Foster SL, Rothholz MC. Pharmacist involvement with immunizations: a decade of professional advancement. J Am Pharm Assoc. 2006;46(2):168-179.
  2. Accreditation Standards and Guidelines for the Professional Program in Pharmacy Leading to the Doctor of Pharmacy Degree. Accreditation Council on Pharmacy Education Web site. Available at: www.acpe-accredit.org/....pdf. Accessed June 5, 2007.
  3. National Immunization Program Web site (Centers for Disease Control and Prevention). Available at: www.cdc.gov/vaccines/ed/curricular-mtls.htm. Accessed June 5, 2007.
  4. Vaccine Storage and Handling Toolkit. National Immunization Program Web site (Centers for Disease Control and Prevention). Available at: www2a.cdc.gov/nip/isd/shtoolkit/splash.html. Accessed June 5, 2007.
  5. Centers for Disease Control and Prevention. Vaccine management: recommendations for storage and handling of selected biologicals. Atlanta, Ga: Centers for Disease Control and Prevention, National Center for Prevention Services Division of Immunization; 2007.
  6. Advisory Committee on Immunization Practices. General recommendations on immunizations: recommendations of the advisory committee on immunization practices. MMWR. 2006;55(RR-15):20-24.
  7. Bloodborne Pathogens and Needlestick Prevention. Occupational Safety and Health Administration Web site. Available at: www.osha.gov/SLTC/bloodbornepathogens/. Accessed June 5, 2007.
  8. Hogue MD, Foster SL. Pharmacy-based immunization delivery: a national certificate program for pharmacists. 10th ed. Washington, DC: American Pharmacists Association; 2006.
  9. Mootrey G, Pless R, Iskander J. Surveillance for adverse events following vaccination. In: Manual for the Surveillance of Vaccine-Preventable Diseases. 3rd ed. Atlanta, Ga: Centers for Disease Control and Prevention; 2002.