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Immunity can be achieved actively by using antigens (eg, vaccines, toxoids) or passively by using antibodies (eg, immune globulins, antitoxins). A toxoid is a bacterial toxin that has been modified to be nontoxic but that can still stimulate antibody formation. A vaccine is a suspension of whole (live or inactivated) or fractionated bacteria or viruses rendered nonpathogenic. For vaccines available in the US, see Table 1: Immunization: Vaccines Available in the US. The most current recommendations for immunization are available at the Centers for Disease Control and Prevention (CDC) web site.

Vaccines should be given exactly as recommended on the package insert; however, the interval between a series of doses may be lengthened without losing efficacy. Injection vaccines are usually given IM into the midlateral thigh (in infants and toddlers) or into the deltoid muscle (in school-aged children and adults). Parents should keep a written history of each child's vaccinations.

Risks, Restrictions, and High-Risk Groups

Live-microbial vaccines should not be given simultaneously with blood, plasma, or immune globulin, which can interfere with development of desired antibodies; ideally, such vaccines should be given 2 wk before or 6 to 12 wk after the immune globulins.

Immunocompromised patients should not receive live-virus vaccines, which could provoke severe or fatal infections. In patients receiving short-term (ie, < 14 days) immunosuppressive therapy (eg, corticosteroids, antimetabolites, alkylating compounds, radiation), live-virus vaccines should be withheld until after treatment. Patients receiving longer-term immunosuppressive therapy may receive inactivated vaccines such as DTaP; ≥ 3 mo after immunosuppressive therapy is stopped, they should be given an additional dose of inactivated vaccine and may receive live-virus vaccines.

Table 1
Vaccines Available in the US Vaccine Type Route Anthrax Inactivated bacteria sc BCG (for tuberculosis) Live Mycobacteria bovis Intradermal or sc Diphtheria-tetanus-acellular pertussis (DTaP or Tdap) Toxoids and inactivated bacterial components IM DTaP plus Haemophilus influenzae type b conjugate (DTaP-Hib) Toxoids, inactivated whole bacteria, and bacterial polysaccharide conjugated to protein IM DTaP-hepatitis B-polio (DTaP-HepB-IPV) Toxoids, recombinant viral antigen, and inactivated poliovirus IM DTaP-IPV Toxoids, inactivated bacteria, and inactivated poliovirus IM DTaP-IPV-Hib Toxoids, inactivated bacteria, inactivated poliovirus, and bacterial polysaccharide conjugated to protein IM Hepatitis A (HepA) Inactivated virus IM Hepatitis B (HepB) Recombinant viral antigen IM Hepatitis A and hepatitis B Inactivated virus plus recombinant viral antigens IM Haemophilus influenzae type b conjugate (Hib) Bacterial polysaccharide conjugated to protein IM HbCV plus Hep B Bacterial polysaccharide conjugate plus inactivated viral antigen IM Herpes zoster Live varicella virus sc Human papillomavirus (HPV) Noninfectious viruslike particles IM Influenza, types A and B Inactivated virus or viral components IM Influenza Live virus Intranasal Japanese encephalitis Inactivated virus sc Measles Live virus sc Measles and rubella Live viruses sc Measles and mumps Live viruses sc Measles-mumps-rubella (MMR) Live viruses sc Measles-mumps-rubella-varicella (MMRV) Live viruses sc Meningococcal, polysaccharide (MPSV4) Bacterial polysaccharides of serotypes A/C/Y/W-135 sc Meningococcal, conjugate (MCV4) Bacterial polysaccharides of serotypes A/C/Y/W-135 conjugated to diphtheria toxoid protein IM Mumps Live virus sc Pneumococcal, polysaccharide (PPV) Bacterial polysaccharides of 23 pneumococcal types IM or sc Pneumococcal, conjugate (PCV) Polysaccharides of 7 types, conjugated to diphtheria toxin IM Poliovirus (IPV) Inactivated viruses of all 3 serotypes IM Rabies Inactivated virus Intradermal* or sc Rotavirus Live virus Oral Rubella Live virus sc Smallpox Live vaccinia virus Intradermal via multiple puncture device Tetanus Inactivated toxin (toxoid) IM† Tetanus and diphtheria toxoids adsorbed (Td)‡ or diphtheria-tetanus (DT) Inactivated toxins (toxoids) IM† Tuberculosis (see BCG) — — Typhoid Capsular polysaccharide IM Typhoid Live-attenuated vaccine po Varicella Live virus sc Yellow fever Live virus sc *Intradermal dose is lower and used only for preexposure vaccination. †Preparations with adjuvants should be given IM. ‡Td contains the same amount of tetanus toxoid as DTP or DT but a reduced dose of diphtheria toxoid. Modified from General Recommendations on Immunization. Recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report 43:1, January 28, 1994. Updated through Center for Biologics Evaluation and Research of U.S. Food and Drug Administration, 2008.

Asplenic patients are predisposed to overwhelming bacteremic infection, usually due to Streptococcus pneumoniae, Neisseria meningitidis, or Haemophilus influenzae type b (Hib). They should be given the following:

• Hib conjugate (HbCV) vaccine
• Meningococcal polysaccharide vaccine
• Annual influenza vaccine
• Pneumococcal conjugate (if age < 5 yr) or polysaccharide (if age > 5 yr) vaccine

Before solid organ transplantation, patients should receive all appropriate vaccines. Patients who have had hematopoietic cell transplantation should be considered unimmunized and should receive repeat doses of all appropriate vaccines.

Patients with AIDS should generally receive inactivated vaccines (eg, DTP, polio [IPV], HbCV) according to routine recommendations but should usually not receive live-virus or bacterial vaccines (eg, measles-mumps-rubella, OPV, BCG). However, they can receive measles-mumps-rubella if immunosuppression is not severe because naturally occurring measles can cause severe, often fatal infection in AIDS patients, and measles-mumps-rubella vaccine rarely causes serious complications.

Risks of vaccines should be discussed with patients. Parents should give written consent for vaccination of their children. In the US, selected events that occur after routine vaccination must be reported to the manufacturer, the US Department of Health and Human Services, and the Centers for Disease Control and Prevention's Vaccine Adverse Event Reporting System (VAERS). Forms and instructions can be obtained by calling 800-822-7967 (Health and Human Services) or from the VAERS web site (www.vaers.hhs.gov).

A temperature of > 39° C requires delaying vaccination, but minor infections, such as the common cold (even with low-grade fever), do not. Some vaccines produced in cell culture systems contain trace amounts of egg antigens. Although egg allergies are often considered contraindications to these vaccines, the vaccines do not appear to cause significant adverse reactions in patients who can eat foods that contain eggs, such as bread or cookies. A history of other allergic reactions may contraindicate use of certain vaccines (see Table 2: Immunization: Common Vaccinations for Adults).

Pregnancy is a relative contraindication to vaccination with human papillomavirus (HPV), measles-mumps-rubella, pneumococcal pneumonia, varicella, and other live-virus vaccines.

Concern has been raised about the safety in infants of thimerosal, an Hg-based preservative present in some vaccines, but there is no evidence of harm. In particular, there is no convincing evidence that vaccines containing thimerosal are related to the development of autism. Nevertheless, most manufacturers have developed thimerosal-free vaccines for use in infants. Information about vaccines that currently contain low levels of Hg or thimerosal is available at the Institute for Vaccine Safety web site.

Patients with a fluctuating or progressive neurologic disorder, such as Guillain-Barré syndrome, should not be vaccinated until their condition has been stable for at least 1 yr because cerebral irritation is a risk. If a neurologic disorder is stable, vaccinations should proceed normally. The risk in patients with multiple sclerosis is unknown.

Last full review/revision July 2008 by Fred H. Rubin, MD

Content last modified July 2008