Few medical interventions of the past century can rival the effect that immunization has had on longevity, economic savings, and quality of life. Seventeen diseases are now preventable through vaccines routinely administered to children and adults in the United States (Table 148-1), and most vaccine-preventable diseases of childhood are at historically low levels (Table 148-2). Health care providers deliver the vast majority of vaccines in the United States in the course of providing routine health services and therefore play an integral role in the nation’s public health system.
Direct and Indirect Effects
Immunizations against specific infectious diseases protect individuals against infection and thereby prevent symptomatic illnesses. Specific vaccines may blunt the severity of clinical illness (e.g., rotavirus vaccines and severe gastroenteritis) or reduce complications (e.g., zoster vaccines and postherpetic neuralgia). Some immunizations also reduce transmission of infectious disease agents from immunized people to others, thereby reducing the impact of infection spread. This indirect impact is known as herd immunity. The level of immunization in a population that is required to achieve indirect protection of unimmunized people varies substantially with the specific vaccine.
TABLE 148-1Diseases Preventable with Vaccines Routinely Administered in the United States to Children and/or Adults ||Download (.pdf) TABLE 148-1Diseases Preventable with Vaccines Routinely Administered in the United States to Children and/or Adults
|Condition ||Target Population(s) for Routine Use |
|Pertussis ||Children, adolescents, adults |
|Diphtheria ||Children, adolescents, adults |
|Tetanus ||Children, adolescents, adults |
|Poliomyelitis ||Children |
|Measles ||Children |
|Mumps ||Children |
|Rubella, congenital rubella syndrome ||Children |
|Hepatitis B ||Children |
|Haemophilus influenzae type b infection ||Children |
|Hepatitis A ||Children |
|Influenza ||Children, adolescents, adults |
|Varicella ||Children |
|Invasive pneumococcal disease ||Children, older adults |
|Meningococcal disease ||Adolescents |
|Rotavirus infection ||Infants |
|Human papillomavirus infection, cervical and anogenital cancers ||Adolescents and young adults |
|Zoster ||Older adults |
Since childhood vaccines have become widely available in the United States, major declines in rates of vaccine-preventable diseases among both children and adults have become evident (Table 148-2). For example, vaccination of children <5 years of age against seven types of Streptococcus pneumoniae led to a >90% overall reduction in invasive disease caused by those types. A series of childhood vaccines targeting 13 vaccine-preventable diseases in a single birth cohort leads to prevention of 42,000 premature deaths and 20 million illnesses and saves nearly $70 billion (U.S.).
Control, Elimination, and Eradication of Vaccine-Preventable Diseases
Immunization programs are associated with the goals of controlling, eliminating, or eradicating a disease. Control of a vaccine-preventable disease reduces poor illness outcomes and often limits the disruptive impacts associated with outbreaks of disease in communities, schools, and institutions. Control programs can also reduce absences from work for ill persons and for parents caring for sick children, decrease absences from school, and limit health care utilization associated with treatment visits.
Elimination of a disease is a more demanding goal than control, usually requiring the reduction to zero of cases in a defined geographic area but sometimes defined as reduction in the indigenous sustained transmission of an infection in a geographic area. As of 2013, the United States had eliminated indigenous transmission of measles, rubella, poliomyelitis, and diphtheria. Importation of pathogens from other parts of the world continues to be important, and public health efforts are intended to react promptly to such cases and to limit forward spread of the infectious agent.
Eradication of a disease is achieved when its elimination can be sustained without ongoing interventions. The only vaccine-preventable disease of humans that has been globally eradicated thus far is smallpox. Although smallpox vaccine is no longer given routinely, the disease has not reemerged naturally because all chains of human transmission were interrupted through earlier vaccination efforts and humans were the only natural reservoir of the virus. Currently, a major health initiative is targeting the global eradication of polio. Sustained transmission of polio has been eliminated from most nations but has never been interrupted in three countries—Afghanistan, Nigeria, and Pakistan—while recent outbreaks in Syria and the Horn of Africa underscore that other countries remain at risk for importation until these reservoirs have been addressed. Detection of a case of disease that has been targeted for eradication or elimination is considered a sentinel event that could permit the infectious agent to become reestablished in the community or region. Therefore, such episodes must be promptly reported to public health authorities.
Outbreak Detection and Control
Clusters of cases of a vaccine-preventable disease detected in an institution, a medical practice, or a community may signal important changes in the pathogen, vaccine, or environment. Several factors can give rise to increases in vaccine-preventable disease, including (1) low rates of immunization that result in an accumulation of susceptible people (e.g., measles resurgence among vaccination abstainers); (2) changes in the infectious agent that permit it to escape vaccine-induced protection (e.g., non-vaccine-type pneumococci); (3) waning of vaccine-induced immunity (e.g., pertussis among adolescents and adults vaccinated in early childhood); and (4) point-source introductions of large inocula (e.g., food-borne exposure to hepatitis A virus). Reporting episodes of outbreak-prone diseases to public health authorities can facilitate recognition of clusters that require further interventions.
TABLE 148-2Decline in Vaccine-Preventable Diseases in the United States following Widespread Implementation of National Vaccine Recommendations ||Download (.pdf) TABLE 148-2Decline in Vaccine-Preventable Diseases in the United States following Widespread Implementation of National Vaccine Recommendations
|Condition ||Annual No. of Prevaccine Cases (Average) ||No. of Cases Reported in 2012a ||Reduction (%) in Cases After Widespread Vaccination |
|Smallpox ||29,005 ||0 ||100 |
|Diphtheria ||21,053 ||1 ||≥99 |
|Measles ||530,217 ||55 ||≥99 |
|Mumps ||162,344 ||229 ||≥99 |
|Pertussis ||200,752 ||48,277 ||76 |
|Polio (paralytic) ||16,316 ||0 ||100 |
|Rubella ||47,745 ||9 ||>99 |
|Congenital rubella syndrome ||152 ||2 ||99 |
|Tetanus ||580 ||37 ||94 |
|Haemophilus influenzae type b infection ||20,000 ||30b ||99 |
|Hepatitis A ||117,333 ||2,890c ||98 |
|Hepatitis B (acute) ||66,232 ||18,800c ||72 |
|Invasive pneumococcal infection: all ages ||63,067 ||31,600d ||50 |
|Invasive pneumococcal infection: <5 years of age ||16,069 ||1,800d ||89 |
|Varicella ||4,085,120 ||216,511 ||95 |
Recognition of suspected cases of diseases targeted for elimination or eradication—along with other diseases that require urgent public health interventions, such as contact tracing, administration of chemo- or immunoprophylaxis, or epidemiologic investigation for common-source exposure—is typically associated with special reporting requirements. Many diseases against which vaccines are routinely used, including measles, pertussis, Haemophilus influenzae type b invasive disease, and varicella, are nationally notifiable. Clinicians and laboratory staff have a responsibility to report some vaccine-preventable disease occurrences to local or state public health authorities according to specific case-definition criteria. All providers should be aware of state or city disease-reporting requirements and the best ways to contact public health authorities. A prompt response to vaccine-preventable disease outbreaks can greatly enhance the effectiveness of control measures.
Several international health initiatives currently focus on reducing vaccine-preventable diseases in regions throughout the world. These efforts include improving access to new and underutilized vaccines, such as pneumococcal conjugate, rotavirus, human papillomavirus (HPV), and meningococcal A conjugate vaccines. The American Red Cross, the World Health Organization (WHO), the United Nations Foundation, the United Nations Children’s Fund (UNICEF), and the Centers for Disease Control and Prevention (CDC) are partners in the Measles & Rubella Initiative, which targets reduction of worldwide measles deaths by 95% from 2000 to 2015. During 2000–2011, global measles mortality rates declined by 71%—i.e., from an estimated 548,000 deaths in 2000 to 158,000 deaths in 2011. Rotary International, UNICEF, the CDC, and the WHO are leading partners in the global eradication of polio, an endeavor that reduced the annual number of paralytic polio cases from 350,000 in 1988 to <250 in 2012. The GAVI Alliance and the Bill and Melinda Gates Foundation have brought substantial momentum to global efforts to reduce vaccine-preventable diseases, expanding on earlier efforts by the WHO, UNICEF, and governments in developed and developing countries.
Enhancing Immunization in Adults
Although immunization has become a centerpiece of routine pediatric medical visits, it has not been as well integrated into routine health care visits for adults. This chapter focuses on immunization principles and vaccine use in adults. Accumulating evidence suggests that immunization coverage can be increased through efforts directed at consumer-, provider-, institution-, and system-level factors. The literature suggests that the application of multiple strategies is more effective at raising coverage rates than is the use of any single strategy.
Recommendations for Adult Immunizations
The CDC’s Advisory Committee on Immunization Practices (ACIP) is the main source of recommendations for administration of vaccines approved by the U.S. Food and Drug Administration (FDA) for use in children and adults in the U.S. civilian population. The ACIP is a federal advisory committee that consists of 15 voting members (experts in fields associated with immunization) appointed by the Secretary of the U.S. Department of Health and Human Services; 8 ex officio members representing federal agencies; and 26 nonvoting representatives of various liaison organizations, including major medical societies and managed-care organizations. The ACIP recommendations are available at www.cdc.gov/vaccines/hcp/acip-recs/. These recommendations are harmonized to the greatest extent possible with vaccine recommendations made by other organizations, including the American College of Obstetricians and Gynecologists, the American Academy of Family Physicians, and the American College of Physicians.
Adult Immunization Schedules
Immunization schedules for adults in the United States are updated annually and can be found online (www.cdc.gov/vaccines/schedules/hcp/adult.html). In January, the schedules are published in American Family Physician, Annals of Internal Medicine, and Morbidity and Mortality Weekly Report (www.cdc.gov/mmwr). The adult immunization schedules for 2013 are summarized in Fig. 148-1. Additional information and specifications are contained in the footnotes to these schedules. In the time between annual publications, additions and changes to schedules are published as Notices to Readers in Morbidity and Mortality Weekly Report.
Recommended adult immunization schedules, United States, 2013. For complete statements by the Advisory Committee on Immunization Practices (ACIP), visit www.cdc.gov/vaccines/hcp/acip-recs/.
IMMUNIZATION PRACTICE STANDARDS
Administering immunizations to adults involves a number of processes, such as deciding whom to vaccinate, assessing vaccine contraindications and precautions, providing vaccine information statements (VISs), ensuring appropriate storage and handling of vaccines, administering vaccines, and maintaining vaccine records. In addition, provider reporting of adverse events that follow vaccination is an essential component of the vaccine safety monitoring system.
Deciding Whom to Vaccinate
Every effort should be made to ensure that adults receive all indicated vaccines as expeditiously as possible. When adults present for care, their immunization history should be assessed and recorded, and this information should be used to identify needed vaccinations according to the most current version of the adult immunization schedule. Decision-support tools incorporated into electronic health records can provide prompts for needed vaccinations. Standing orders, which are often used for routinely indicated vaccines (e.g., influenza and pneumococcal vaccines), permit a nurse or another approved licensed practitioner to administer vaccines without a specific physician order, thus lowering barriers to adult immunization.
Assessing Contraindications and Precautions
Before vaccination, all patients should be screened for contraindications and precautions. A contraindication is a condition that increases the risk of a serious adverse reaction to vaccination. A vaccine should not be administered when a contraindication is documented. For example, a history of an anaphylactic reaction to a dose of vaccine or to a vaccine component is a contraindication for further doses. A precaution is a condition that may increase the risk of an adverse event or that may compromise the ability of the vaccine to evoke immunity (e.g., administering measles vaccine to a person who has recently received a blood transfusion and may consequently have transient passive immunity to measles virus). Normally, a vaccine is not administered when a precaution is noted. However, situations may arise when the benefits of vaccination outweigh the estimated risk of an adverse event, and the provider may decide to vaccinate the patient despite the precaution.
In some cases, contraindications and precautions are temporary and may lead to mere deferral of vaccination until a later time. For example, moderate or severe acute illness with or without fever is generally considered a transient precaution to vaccination and results in postponement of vaccine administration until the acute phase has resolved; thus the superimposition of adverse effects of vaccination on the underlying illness and the mistaken attribution of a manifestation of the underlying illness to the vaccine are avoided. Contraindications and precautions to vaccines licensed in the United States for use in civilian adults are summarized in Table 148-3. It is important to recognize conditions that are not contraindications in order not to miss opportunities for vaccination. For example, in most cases, mild acute illness (with or without fever), a history of a mild to moderate local reaction to a previous dose of the vaccine, and breast-feeding are not contraindications to vaccination.
History of Immediate Hypersensitivity to a Vaccine Component
A severe allergic reaction (e.g., anaphylaxis) to a previous dose of a vaccine or to one of its components is a contraindication to vaccination. While most vaccines have many components, substances to which individuals are most likely to have had a severe allergic reaction include egg protein, gelatin, and yeast. In addition, although natural rubber (latex) is not a vaccine component, some vaccines are supplied in vials or syringes that contain natural rubber latex. These vaccines can be identified by the product insert and should not be administered to persons who report a severe (anaphylactic) allergy to latex unless the benefit of vaccination clearly outweighs the risk for a potential allergic reaction. The much more common local or contact hypersensitivity to latex, such as to medical gloves (which contain synthetic latex that is not linked to allergic reactions), is not a contraindication to administration of a vaccine supplied in a vial or syringe that contains natural rubber latex. Vaccines routinely indicated for adults that, as of December 2012, were sometimes supplied in a vial or syringe containing natural rubber include Havrix hepatitis A vaccine (syringe); Vaqta hepatitis A vaccine (vial and syringe); Engerix-B hepatitis B vaccine (syringe); Recombivax HB hepatitis B vaccine (vial); Cervarix HPV vaccine (syringe); Fluarix, Fluvirin, Agriflu, and Flucelvax influenza vaccines (syringe); Adacel and Boostrix Tdap (tetanus and diphtheria toxoids and acellular pertussis) vaccines (syringe); Td (tetanus and diphtheria toxoids) vaccines (syringe); Twinrix hepatitis A and B vaccine (syringe); and Menomune meningococcal polysaccharide vaccine (vial).
Live-virus vaccines are contraindicated during pregnancy because of the theoretical risk that vaccine virus replication will cause congenital infection or have other adverse effects on the fetus. Most live-virus vaccines, including varicella vaccine, are not secreted in breast milk; therefore, breast-feeding is not a contraindication for live-virus or other vaccines. Pregnancy is not a contraindication to administration of inactivated vaccines, but most are avoided during pregnancy because relevant safety data are limited. Two inactivated vaccines, Tdap vaccine and inactivated influenza vaccine, are routinely recommended for pregnant women in the United States. Tdap vaccine is recommended during each pregnancy, regardless of prior vaccination status, in order to prevent pertussis in neonates. Annual influenza vaccination is recommended for all persons 6 months of age and older, regardless of pregnancy status. Some other vaccines, such as meningococcal vaccines, may be given to pregnant women in certain circumstances.
TABLE 148-3Contraindications and Precautions for Commonly Used Vaccines in Adults ||Download (.pdf) TABLE 148-3Contraindications and Precautions for Commonly Used Vaccines in Adults
|Vaccine Formulation ||Contraindications and Precautions |
|All vaccines ||Contraindication |
| ||Severe allergic reaction (e.g., anaphylaxis) after a previous vaccine dose or to a vaccine component |
| ||Precaution |
| ||Moderate or severe acute illness with or without fever. Defer vaccination until illness resolves. |
|Td ||Precautions |
| ||GBS within 6 weeks after a previous dose of TT-containing vaccine |
| ||History of arthus-type hypersensitivity reactions after a previous dose of TD- or DT-containing vaccines (including MCV4). Defer vaccination until at least 10 years have elapsed since the last dose. |
|Tdap ||Contraindication |
| ||History of encephalopathy (e.g., coma or prolonged seizures) not attributable to another identifiable cause within 7 days of administration of a vaccine with pertussis components, such as DTaP or Tdap |
| ||Precautions |
| ||GBS within 6 weeks after a previous dose of TT-containing vaccine |
| ||Progressive or unstable neurologic disorder, uncontrolled seizures, or progressive encephalopathy. Defer vaccination until a treatment regimen has been established and the condition has stabilized. |
| ||History of arthus-type hypersensitivity reactions after a previous dose of TT- or DT-containing vaccines (including MCV4). Defer vaccination until at least 10 years have elapsed since the last dose. |
|HPV ||Contraindication |
| ||History of immediate hypersensitivity to yeast (for Gardasil) |
| ||Precaution |
| ||Pregnancy. If a woman is found to be pregnant after initiation of the vaccination series, the remainder of the 3-dose regimen should be delayed until after completion of the pregnancy. If a vaccine dose has been administered during pregnancy, no intervention is needed. Exposure to Gardasil during pregnancy should be reported to Merck (800-986-8999); exposure to Cervarix during pregnancy should be reported to GlaxoSmithKline (888-452-9622). |
|MMR ||Contraindications |
| ||History of immediate hypersensitivity reaction to gelatina or neomycin |
| ||Pregnancy |
| ||Known severe immunodeficiency (e.g., hematologic and solid tumors; chemotherapy; congenital immunodeficiency; long-term immunosuppressive therapy; severe immunocompromise due to HIV infection) |
| ||Precautions |
| ||Recent receipt (within 11 months) of antibody-containing blood product |
| ||History of thrombocytopenia or thrombocytopenic purpura |
|Varicella ||Contraindications |
| ||Pregnancy |
| ||Known severe immunodeficiency |
| ||History of immediate hypersensitivity reaction to gelatina or neomycin |
| ||Precaution |
| ||Recent receipt (within 11 months) of antibody-containing blood product |
|Influenza, inactivated, injectable || |
History of severe allergic reaction (e.g., anaphylaxis) to egg proteinb (note: not a precaution for Flublok recombinant influenza vaccine, which is approved for persons 18–49 years of age and is manufactured without the use of eggs)
History of GBS within 6 weeks after a previous influenza vaccine dose
|Influenza, live attenuated nasal spray || |
History of severe allergic reaction (e.g., anaphylaxis) to egg proteinb
Age ≥50 years
Immunosuppression, including that caused by medications or by HIV infection; known severe immunodeficiency (e.g., hematologic and solid tumors; chemotherapy; congenital immunodeficiency; long-term immunosuppressive therapy; severe immunocompromise due to HIV infection)
Certain chronic medical conditions, such as diabetes mellitus; chronic pulmonary disease (including asthma); chronic cardiovascular disease (except hypertension); renal, hepatic, neurologic/neuromuscular, hematologic, or metabolic disorders
Close contact with severely immunosuppressed persons who require a protected environment, such as isolation in a bone marrow transplantation unit
Close contact with persons with lesser degrees of immunosuppression (e.g., persons receiving chemotherapy or radiation therapy who are not being cared for in a protective environment; persons with HIV infection) is not a contraindication or a precaution. Health care personnel in neonatal intensive care units or oncology clinics may receive live attenuated influenza vaccine.
History of GBS within 6 weeks of a previous influenza vaccine dose
Receipt of specific antiviral agents (i.e., amantadine, rimantadine, zanamivir, or oseltamivir) with 48 h before vaccination
|Pneumococcal polysaccharide ||None, other than those listed for all vaccines |
|Pneumococcal conjugate ||None, other than those listed for all vaccines |
|Hepatitis A ||Precaution |
| ||Pregnancy |
|Hepatitis B ||Contraindication |
| ||History of immediate hypersensitivity to yeast |
|Meningococcal conjugate || |
History of severe allergic reaction to dry natural rubber (latex) (certain vaccine formulations; see text)
|Meningococcal polysaccharide || |
History of severe allergic reaction to dry natural rubber (latex)
|Zoster ||Contraindications |
| ||Age <50 years |
| ||Pregnancy |
| ||Known severe immunodeficiency |
| ||History of immediate hypersensitivity reaction to gelatina or neomycin |
| ||Precaution |
| ||Receipt of specific antiviral agents (i.e., acyclovir, famciclovir, or valacyclovir) within 24 h before vaccination |
Live-virus vaccines elicit an immune response due to replication of the attenuated (weakened) vaccine virus that is contained by the recipient’s immune system. In persons with compromised immune function, enhanced replication of vaccine viruses is possible and could lead to disseminated infection with the vaccine virus. For this reason, live-virus vaccines are contraindicated for persons with severe immunosuppression, the definition of which may vary with the vaccine. Severe immunosuppression may be caused by many disease conditions, including HIV infection and hematologic or generalized malignancy. In some of these conditions, all affected persons are severely immunocompromised. In others (e.g., HIV infection), the degree to which the immune system is compromised depends on the severity of the condition, which in turn depends on the stage of disease or treatment. For example, measles-mumps-rubella (MMR) vaccine may be given to HIV-infected persons who are not severely immunocompromised. Severe immunosuppression may also be due to therapy with immunosuppressive agents, including high-dose glucocorticoids. In this situation, the dose, duration, and route of administration may influence the degree of immunosuppression.
VACCINE INFORMATION STATEMENTS
A VIS is a one-page (two-sided) information sheet produced by the CDC that informs vaccine recipients (or their parents or legal representatives) about the benefits and risks of a vaccine. VISs are mandated by the National Childhood Vaccine Injury Act (NCVIA) of 1986 and—whether the vaccine recipient is a child or an adult—must be provided for any vaccine covered by the Vaccine Injury Compensation Program. As of July 2011, vaccines that are covered by the NCVIA and that are licensed for use in adults include Td, Tdap, hepatitis A, hepatitis B, HPV, trivalent inactivated influenza, trivalent live intranasal influenza, MMR, 13-valent pneumococcal conjugate, meningococcal, polio, and varicella vaccines. When combination vaccines for which no separate VIS exists are given (e.g., hepatitis A and B combination vaccine), all relevant VISs should be provided. VISs also exist for some vaccines not covered by the NCVIA, such as pneumococcal polysaccharide, Japanese encephalitis, rabies, zoster, typhoid, and yellow fever vaccines. The use of these VISs is encouraged but is not mandated.
All current VISs are available on the Internet at two websites: the CDC’s Vaccines & Immunizations site (www.cdc.gov/vaccines/hcp/vis/) and the Immunization Action Coalition’s site (www.immunize.org/vis/). (The latter site also includes translations of the VISs.) VISs from these sites can be downloaded and printed.
Injectable vaccines are packaged in multidose vials, single-dose vials, or manufacturer-filled single-dose syringes. The live attenuated nasal-spray influenza vaccine is packaged in single-dose sprayers. Oral typhoid vaccine is packaged in capsules. Some vaccines, such as MMR, varicella, zoster, and meningococcal polysaccharide vaccines, come as lyophilized (freeze-dried) powders that must be reconstituted (i.e., mixed with a liquid diluent) before use. The lyophilized powder and the diluent come in separate vials. Diluents are not interchangeable but rather are specifically formulated for each type of vaccine; only the specific diluent provided by the manufacturer for each type of vaccine should be used. Once lyophilized vaccines have been reconstituted, their shelf-life is limited and they must be stored under appropriate temperature and light conditions. For example, varicella and zoster vaccines must be protected from light and administered within 30 min of reconstitution; MMR vaccine likewise must be protected from light but can be used up to 8 h after reconstitution. Single-dose vials of meningococcal polysaccharide vaccine must be used within 30 min of reconstitution, while multidose vials must be used within 35 days.
Vaccines are stored either at refrigerator temperature (2–8°C) or at freezer temperature (–15°C or colder). In general, inactivated vaccines (e.g., inactivated influenza, pneumococcal polysaccharide, and meningococcal conjugate vaccines) are stored at refrigerator temperature, while vials of lyophilized-powder live-virus vaccines (e.g., varicella, zoster, and MMR vaccines) are stored at freezer temperature. Diluents for lyophilized vaccines may be stored at refrigerator or room temperature. Live attenuated influenza vaccine—a live-virus liquid formulation administered by nasal spray—is stored at refrigerator temperature.
Vaccine storage and handling errors can result in the loss of vaccines worth millions of dollars, and administration of improperly stored vaccines may elicit inadequate immune responses in patients. To improve the standard of vaccine storage and handling practices, the CDC has published detailed guidance (available at www.cdc.gov/vaccines/recs/storage/toolkit/storage-handling-toolkit.pdf). For vaccine storage, the CDC recommends stand-alone units—i.e., self-contained units that either refrigerate or freeze but do not do both—as these units maintain the required temperatures better than combination refrigerator/freezer units. Dormitory-style combined refrigerator/freezer units should never be used for vaccine storage.
The temperature of refrigerators and freezers used for vaccine storage must be monitored and the temperature recorded at least twice each workday. Ideally, continuous thermometers that measure and record temperature all day and all night are used, and minimum and maximum temperatures are read and documented each workday. The CDC recommends the use of calibrated digital thermometers with a probe in a glycol-filled bottle; more detailed information on specifications of storage units and temperature-monitoring devices is provided at the link given above.
ADMINISTRATION OF VACCINES
Most parenteral vaccines recommended for routine administration to adults in the United States are given by either the IM or the SC route; one influenza vaccine formulation approved for use in adults 18–64 years of age is given intradermally. Live-virus vaccines such as varicella, zoster, and MMR are given SC. Most inactivated vaccines are given IM, except for meningococcal polysaccharide vaccine, which is given SC. The 23-valent pneumococcal polysaccharide vaccine may be given either IM or SC, but IM administration is preferred because it is associated with a lower risk of injection-site reactions.
Vaccines given to adults by the SC route are administered with a 5/8-inch needle into the upper outer-triceps area. Vaccines administered to adults by the IM route are injected into the deltoid muscle (Fig. 148-2) with a needle whose length should be selected on the basis of the recipient’s sex and weight to ensure adequate penetration into the muscle. Current guidelines indicate that, for men and women weighing <152 lbs (<70 kg), a 1-inch needle is sufficient; for women weighing 152–200 lbs (70–90 kg) and men weighing 152–260 lbs (70–118 kg), a 1- to 1.5-inch needle is needed; and for women weighing >200 lbs (>90 kg) and men weighing >260 lbs (>118 kg), a 1.5-inch needle is required. Additional illustrations of vaccine injection locations and techniques may be found at www.immunize.org/catg.d/p2020a.pdf.
Technique for IM administration of vaccine. (Photo credit: James Gathany, Centers for Disease Control and Prevention; accessible at Public Health Image Library, www.cdc.gov. PHIL ID#9420.)
Aspiration, the process of pulling back on the plunger of the syringe after skin penetration but prior to injection, is not necessary because no large blood vessels are present at the recommended vaccine injection sites.
Multiple vaccines can be administered at the same visit; indeed, administration of all needed vaccines at one visit is encouraged. Studies have shown that vaccines are as effective when administered simultaneously as they are individually, and simultaneous administration of multiple vaccines is not associated with an increased risk of adverse effects. If more than one vaccine must be administered in the same limb, the injection sites should be separated by 1–2 inches so that any local reactions can be differentiated. If a vaccine and an immune globulin preparation are administered simultaneously (e.g., Td vaccine and tetanus immune globulin), a separate anatomic site should be used for each injection.
For certain vaccines (e.g., HPV vaccine and hepatitis B vaccine), multiple doses are required for an adequate and persistent antibody response. The recommended vaccination schedule specifies the interval between doses. Many adults who receive the first dose in a multiple-dose vaccine series do not complete the series or do not receive subsequent doses within the recommended interval. For example, at least one-third of adults who receive the first dose of hepatitis B vaccine in the three-dose series do not complete the series. In these circumstances, vaccine efficacy and/or the duration of protection may be compromised. Providers should implement recall systems that will prompt patients to return for subsequent doses in a vaccination series at the appropriate intervals. With the exception of oral typhoid vaccination, an interruption in the schedule does not require restarting of the entire series or the addition of extra doses.
Syncope may follow vaccination, especially in adolescents and young adults. Serious injuries, including skull fracture and cerebral hemorrhage, have occurred. Adolescents and adults should be seated or lying down during vaccination. The majority of reported syncope episodes after vaccination occur within 15 min. The ACIP recommends that vaccine providers strongly consider observing patients, particularly adolescents, with patients seated or lying down for 15 min after vaccination. If syncope develops, patients should be observed until the symptoms resolve.
Anaphylaxis is a rare complication of vaccination. All facilities providing immunizations should have an emergency kit containing aqueous epinephrine for administration in the event of a systemic anaphylactic reaction.
MAINTENANCE OF VACCINE RECORDS
All vaccines administered should be fully documented in the patient’s permanent medical record. Documentation should include the date of administration, the name or common abbreviation of the vaccine, the vaccine lot number and manufacturer, the administration site, the VIS edition, the date the VIS was provided, and the name, address, and title of the person who administered the vaccine. Increasing use of two-dimensional bar codes on vaccine vials and syringes that can be scanned for data entry into compatible electronic medical records and immunization information systems may facilitate more complete and accurate recording of required information.
VACCINE SAFETY MONITORING AND ADVERSE EVENT REPORTING
Prelicensure Evaluations of Vaccine Safety
Before vaccines are licensed by the FDA, they are evaluated in clinical trials with volunteers. These trials are conducted in three progressive phases. Phase 1 trials are small, usually involving fewer than 100 volunteers. Their purposes are to provide a basic evaluation of safety and to identify common adverse events. Phase 2 trials, which are larger and may involve several hundred participants, collect additional information on safety and are usually designed to evaluate immunogenicity as well. Data gained from phase 2 trials can be used to determine the composition of the vaccine, the number of doses required, and a profile of common adverse events. Vaccines that appear promising are evaluated in phase 3 trials, which typically involve several hundred to several thousand volunteers and are generally designed to demonstrate vaccine efficacy and provide additional information on vaccine safety.
Postlicensure Monitoring of Vaccine Safety
After licensure, a vaccine’s safety is assessed by several mechanisms. The NCVIA of 1986 requires health care providers to report certain adverse events that follow vaccination. As a mechanism for that reporting, the Vaccine Adverse Event Reporting System (VAERS) was established in 1990 and is jointly managed by the CDC and the FDA. This safety surveillance system collects reports of adverse events associated with vaccines currently licensed in the United States. Adverse events are defined as untoward events that occur after immunization and that might be caused by the vaccine product or vaccination process. While the VAERS was established in response to the NCVIA, any adverse event following vaccination—whether in a child or an adult, and whether or not it is believed to have actually been caused by vaccination—may be reported through the VAERS. The adverse events that health care providers are required to report are listed in the reportable-events table on the VAERS website at vaers.hhs.gov/reportable.htm. Approximately 30,000 VAERS reports are filed annually, with ∼13% reporting serious events resulting in hospitalization, life-threatening illness, disability, or death.
Anyone can file a VAERS report, including health care providers, manufacturers, and vaccine recipients or their parents or guardians. VAERS reports may be submitted online (vaers.hhs.gov/esub/step1) or by completing a paper form requested by email (email@example.com), phone (800-822-7967), or fax (877-721-0366). The VAERS form asks for the following information: the type of vaccine received; the timing of vaccination; the time of onset of the adverse event; and the recipient’s current illnesses or medications, history of adverse events following vaccination, and demographic characteristics (e.g., age and sex). This information is entered into a database. The individual who reported the adverse event then receives a confirmation letter by mail with a VAERS identification number that can be used if additional information is submitted later. In selected cases of serious adverse reaction, the patient’s recovery status may be followed up at 60 days and 1 year after vaccination. The FDA and the CDC have access to VAERS data and use this information to monitor vaccine safety and conduct research studies. VAERS data (minus personal information) are also available to the public.
While the VAERS provides useful information on vaccine safety, this passive reporting system has important limitations. One is that events following vaccination are merely reported; the system cannot assess whether a given type of event occurs more often than expected after vaccination. A second is that event reporting is incomplete and is biased toward events that are believed to be more likely to be due to vaccination and that occur relatively soon after vaccination. To obtain more systematic information on adverse events occurring in both vaccinated and unvaccinated persons, the Vaccine Safety Datalink project was initiated in 1991. Directed by the CDC, this project includes nine managed-care organizations in the United States; member databases include information on immunizations, medical conditions, demographics, laboratory results, and medication prescriptions. The Department of Defense oversees a similar system monitoring the safety of immunizations among active-duty military personnel. In addition, postlicensure evaluations of vaccine safety may be conducted by the vaccine manufacturer. In fact, such evaluations are often required by the FDA as a condition of vaccine licensure.
CONSUMER ACCESS TO AND DEMAND FOR IMMUNIZATION
By removing barriers to the consumer or patient, providers and health care institutions can improve vaccine use. Financial barriers have traditionally been important constraints, particularly among uninsured adults. Even for insured adults, out-of-pocket costs associated with newer, more expensive adult vaccines (e.g., zoster vaccine) are an obstacle to be overcome. After influenza vaccine was included by Medicare for all beneficiaries in 1993, coverage among persons ≥65 years of age doubled (from ∼30% in 1989 to >60% in 1997). Other strategies that enhance patients’ access to vaccination include extended office hours (e.g., evening and weekend hours) and scheduled vaccination-only clinics where waiting times are reduced. Provision of vaccines outside the “medical home” (e.g., through occupational clinics, universities, pharmacies, and retail settings) can expand access for adults who do not make medical visits frequently. Increasing proportions of adults are being vaccinated in these settings.
Health promotion efforts aimed at increasing the demand for immunization are common. Direct-to-consumer advertising by pharmaceutical companies has been used for some newer adolescent and adult vaccines. Efforts to raise consumer demand for vaccines have not increased immunization rates unless implemented in conjunction with other strategies that target strengthening of provider practices or reduction of consumer barriers. Attitudes and beliefs related to vaccination can be considerable impediments to consumer demand. Many adults view vaccines as important for children but are less familiar with vaccinations targeting disease prevention in adults. Several vaccines are recommended for adults with certain medical risk factors, but self-identification as a high-risk individual is relatively rare. Communication research suggests that many adults with chronic diseases may be more motivated to receive a vaccine by a desire to protect their family members rather than to reduce their own risk. Some vaccines are explicitly recommended for persons at relatively low risk of serious complications, with the goal of reducing the risk of transmission to higher-risk contacts. For example, for protection of newborns, vaccinations against influenza and pertussis are recommended for pregnant women and for others who will be around the infant.
STRATEGIES FOR PROVIDERS AND HEALTH CARE FACILITIES
Recommendation from the Provider
Health care providers can have great influence on patients with regard to immunization. A recommendation from a doctor or nurse carries more weight than do recommendations from professional societies or endorsements by celebrities. Providers should be well informed about vaccine risks and benefits so that they can address patients’ common concerns. The CDC, the American College of Physicians, and the American Academy of Family Physicians review and update the schedule for adult immunization on an annual basis and also have developed educational materials to facilitate provider–patient discussions about vaccination (www.cdc.gov/vaccines/hcp.htm).
Medical offices can incorporate a variety of methods to ensure that providers consistently offer specific immunizations to patients with indications for specific vaccines. Decision-support tools have been incorporated into some electronic health records to alert the provider when specific vaccines are indicated. Manual or automated reminders and standing orders have been discussed (see “Deciding Whom to Vaccinate,” above) and have consistently improved vaccination coverage in both office and hospital settings. Most clinicians’ estimates of their own performance diverge from objective measurements of their patients’ immunization coverage; quantitative assessment and feedback have been shown in pediatric and adolescent practices to increase immunization performance significantly. Some health plans have instituted incentives for providers with high rates of immunization coverage. Specialty providers, including obstetrician–gynecologists, may be the only providers serving some high-risk patients with indications for selected vaccines (e.g., Tdap, influenza, or pneumococcal polysaccharide vaccine).
Vaccination against selected communicable diseases is required for attendance at many universities and colleges as well as for service in the U.S. military or in some occupational settings (e.g., child care, laboratory, veterinary, and health care). Immunizations are recommended and sometimes required for travel to certain countries (Chap. 149).
Vaccination of Health Care Staff
A particular area of focus for medical settings is vaccination of health care workers, including those with and without direct patient-care responsibilities. The Joint Commission (which accredits health care organizations), the CDC’s Healthcare Infection Control Practices Advisory Committee, and the ACIP all recommend influenza vaccination of all health care personnel; recommendations also focus on requiring documentation of declination for providers who do not accept annual influenza vaccination. As part of their participation in the Centers for Medicare and Medicaid Services’ Hospital Inpatient Quality Reporting program, acute-care hospitals are required to report the proportion of their health care personnel who have received seasonal influenza vaccine. Some institutions and jurisdictions have added mandates on influenza vaccination of health care workers and have expanded on earlier requirements related to vaccination or proof of immunity for hepatitis B, measles, mumps, rubella, and varicella.
VACCINATION IN NONMEDICAL SETTINGS
Receipt of vaccination in medical offices is most frequent among young children and adults ≥65 years of age. People in these age groups make more office visits and are more likely to receive care in a consistent “medical home” than are older children, adolescents, and nonelderly adults. Vaccination outside the medical home can expand access to those whose health care visits are limited and reduce the burden on busy clinical practices. In some locations, financial constraints related to inventory and storage requirements have led providers to stock few or no vaccines. Outside private office and hospital settings, vaccination may also occur at health department venues, workplaces, retail sites (including pharmacies and supermarkets), and schools or colleges.
When vaccines are given in nonmedical settings, it remains important for standards of immunization practice to be followed. Consumers should be provided with information on how to report adverse events (e.g., via provision of a VIS), and procedures should ensure that documentation of vaccine administration is forwarded to the primary care provider and the state or city public health immunization registry. Detailed documentation may be required for employment, school attendance, and travel. Personalized health records can help consumers keep track of their immunizations, and some occupational health clinics have incorporated automated immunization reports that help employees stay up-to-date with recommended vaccinations. Some pharmacy chain establishments are using automated systems to report immunization information to the state or local immunization information system.
Tracking of immunization coverage at national, state, institution, and practice levels can yield feedback to practitioners and programs and facilitate quality improvement. Healthcare Effectiveness Data and Information Set (HEDIS) measures related to adult immunization facilitate comparison of health plans. The CDC’s National Immunization Survey and National Health Interview Survey provide selected information on immunization coverage among adults and track progress toward achievement of Healthy People 2020 targets for immunization coverage. Influenza and pneumococcal vaccine coverage rates have been higher among persons ≥65 years of age (60–70%) than among high-risk 18- to 64-year-olds. Figures on state-specific immunization coverage with pneumococcal polysaccharide and influenza vaccines (as measured through the CDC’s Behavioral Risk Factor Surveillance System) reveal substantial geographic variation in coverage. There are persistent disparities in adult immunization coverage rates between whites and racial and ethnic minorities. In contrast, racial and economic disparities in immunization of young children have been dramatically reduced during the past 20 years. Much of this progress is attributed to the Vaccines for Children Program, which since 1994 has entitled uninsured children to receive free vaccines.
Although most vaccines developed in the twentieth century targeted common acute infectious diseases of childhood, more recently developed vaccines prevent chronic conditions prevalent among adults. Hepatitis B vaccine prevents hepatitis B–related cirrhosis and hepatocellular carcinoma, zoster vaccine prevents shingles and postherpetic neuralgia, and HPV vaccine prevents some types of cervical cancer, genital warts, and anogenital cancers and may also prevent some oropharyngeal cancers (although this outcome was not studied in prelicensure randomized controlled trials). New targets of vaccine development and research may further broaden the definition of vaccine-preventable disease. Research is ongoing on vaccines to prevent insulin-dependent diabetes mellitus, nicotine addiction, and Alzheimer’s disease. Expanding strategies for vaccine development are incorporating molecular approaches such as DNA, vector, and peptide vaccines. New technologies, such as the use of transdermal and other needle-less routes of administration, are being applied to vaccine delivery.