A four year old boy presents to your office for the first time with a chief complaint of deficient immunizations. His mother, who in prior generations would have been characterized most accurately as an aging hippie, tells you, "He needs his shots to get into school, and he doesn't have any." You confirm that he has not received a single immunization prior to this time. When you ask why he hasn't been immunized, his mother replies that she "hasn't gotten around to it yet," and furthermore, that she "read on the Web and saw on TV that vaccines can hurt you." She then inquires of you, "What shots does a kid actually need, what are vaccines actually made of, and how safe are those immunizations, anyway?"

You perform a physical examination that reveals a healthy boy who is height and weight proportionate and developmentally appropriate for age, has no evidence of concomitant illness, and no abnormal findings upon thorough evaluation.

You then roll your eyes, sigh, and tell your nurse to reschedule your afternoon appointments. You attempt to address the mother's questions and concerns. Following your informative and comprehensive discourse, you obtain informed consent from the mother, then immunize the child using an accelerated schedule to "catch-up" the deficient immunizations. The child tolerates the vaccines without any significant adverse event occurring. After having been provided the remaining required immunizations during subsequent office visits, he begins school the autumn of his 5th year of life protected from vaccine-preventable diseases and meeting the statutory requirements for school entry. He does not acquire a vaccine-preventable disease throughout the remainder of his full and successful life as a professional surfer.

Immunizations children routinely receive currently during childhood are those that protect against hepatitis B, diphtheria, pertussis, tetanus, polio, Haemophilus influenzae type b, Streptococcus pneumoniae, measles, mumps, rubella, and varicella (1). In addition, selected populations receive immunization to protect against hepatitis A and seasonal influenza viruses. The number and ages of administration for these vaccines differ, but the goal of the recommended schedule for childhood immunizations is to provide full protection against vaccine-preventable diseases.

Immunization policy has established the practice of universal childhood immunization to provide vaccines at a time (childhood) an individual is more likely to have contact with health care providers (to increase convenience and minimize delivery costs), to protect children from vaccine-preventable diseases, to establish the foundation for an immune adult population, and to have a enforcement mechanism in order to ensure compliance (required for school entry).

Hepatitis B virus (HBV) vaccine is a recombinant subunit vaccine containing purified Hepatitis B surface antigen, synthesized by insertion of a plasmid encoding for the Hepatitis B surface antigen protein into baker's yeast (2). Hepatitis B vaccine exists as monovalent vaccine (RecombivaxHB, Engerix-B), in combination with Haemophilus influenzae type b vaccine (Comvax), and in combination with Hepatitis A vaccine (Twinrix).

The monovalent Hepatitis B vaccines are administered as a 3 dose series, with the first dose given between birth and 2 months of age, the second dose between 2 months and 4 months of age, and the third dose between 6 months and 18 months of age. Comvax should not be given before 6 weeks of age due to the Haemophilus influenzae type b component, and Twinrix is not yet approved in the United States for use in persons less than 18 years old.

Universal immunization of infants with hepatitis B vaccine is recommended to provide global protection of that birth cohort against hepatitis B infection, to provide vaccine at a time health care visits are otherwise being made, and to afford protection to infants born to mothers who have chronic hepatitis B infection. If hepatitis B vaccination is not provided in infancy at the recommended ages, then at least a 1 month interval should separate administration of the first and second vaccine doses, and at least a 5 month interval should separate the second and third vaccine doses.

The most common adverse reactions to hepatitis B immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently. No causal association with multiple sclerosis or sudden infant death syndrome has been demonstrated.

Diphtheria (D; d) vaccine is a toxoid vaccine that provides formalin-inactivated diphtheria toxin, derived from a potent exotoxin produced by Corynebacterium diphtheriae (3). A "toxoid" is a denatured (nonpathogenic) toxin which stimulates an immune response against the toxin but not necessarily the organism as a whole. Immunization promotes an antibody response that neutralizes the exotoxin, protecting against the cardiotoxic and neurotoxic effects of the exotoxin which is produced during infection. Diphtheria toxoid is combined with tetanus toxoid in a pediatric (DT) and adult (dT) formulation that differs by amount of diphtheria antigen. Diphtheria and tetanus toxoids are also combined with acellular pertussis vaccine (DTaP) for use during routine childhood immunization.

DTaP is given by intramuscular injection as a primary 3 dose series at 2 months, 4 months, and 6 months of age, and as a 2 dose booster series at 12-18 months and 4-6 years. A reduced diphtheria-antigen adult formulation booster (dT) is administered at 11-12 years, and subsequent boosters are then administered at 10 year intervals throughout life.

Tetanus (T) vaccine is a toxoid vaccine that provides formalin-inactivated tetanus toxin, derived from the neuromuscular toxin tetanospasmin produced by Clostridium tetani (3). Immunization promotes an antibody response that neutralizes the toxin. Tetanus vaccine may be monovalent (TT), or combined with either diphtheria toxoid (DT or dT) or with diphtheria toxoid and acellular pertussis (DTaP).

Persons who sustain injuries more likely to become infected with Clostridium tetani (crush wounds with devitalized tissue, deep puncture wounds, wounds contaminated with soil or vegetative matter) should receive a booster dose of tetanus vaccine if at least 5 years have passed since last receiving a tetanus vaccine booster. The most common adverse reactions to tetanus immunization are fever and local reactions at the injection site. Severe allergic reactions, Guillain-Barre syndrome, and brachial neuritis occur rarely.

Three acellular pertussis (aP) vaccines are currently licensed and available for use in the United States (Tripedia, Infanrix, Daptacel). These vaccines are called acellular, to distinguish this formulation from the older whole-cell pertussis vaccine. Whole-cell pertussis vaccine consisted of inactivated ("killed") but otherwise complete Bordetella pertussis bacteria. Administration provided protection against disease but was associated with the potential for adverse effects that occurred frequently and could be quite severe on rare occasion. In order to provide a vaccine that was better tolerated, individual bacterial components that contributed to organism virulence and pathogenicity were identified and purified as individual cell-free (acellular) antigens that comprise the current acellular pertussis vaccines (3,5).

DTaP is given by intramuscular injection as a primary 3 dose series at 2 months, 4 months, and 6 months of age, and as a 2 dose booster series at 12-18 months and 4-6 years. Whole-cell pertussis vaccine was not provided to persons beyond 7 years old, due to the increased incidence of adverse reactions associated with immunization. Currently, acellular pertussis vaccine is not recommended for immunization of persons older than 7 years of age due to the prior experience of whole-cell pertussis vaccine in this age group, although research is currently being conducted to see if adults may safely receive booster doses of the less reactogenic acellular pertussis vaccine to enhance and extend immunity to pertussis.

The most common adverse reactions to acellular pertussis immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently. Rare but potentially serious reactions, including high fevers, prolonged crying, hypotonic-hyporesponsive episodes, and seizures have occurred, but at significantly lower frequency than was true for whole cell pertussis vaccine.

Inactivated polio vaccine (IPV) is a trivalent killed virus vaccine (Salk vaccine; IPOL) that contains formalin-inactivated poliovirus 1, poliovirus 2, and poliovirus 3, which are the three neurovirulent strains. Improvement in manufacturing techniques has enhanced the immunogenicity of inactivated polio vaccine (eIPV). Immunization effectively protects against paralytic poliomyelitis, but may not protect against subclinical enteric infection due to lack of secretory antibody response to inactivated polio vaccine (6).

Inactivated polio vaccine is administered as a 4 dose regimen by intramuscular injection at 2 months, 4 months, between 6 months and 15 months (3 dose primary series), and between 4 years and 6 years of age (booster dose). The most common adverse reactions to inactivated polio immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently. Inactivated polio vaccine cannot cause vaccine associated paralytic poliomyelitis.

A second formulation of polio vaccine, trivalent oral live attenuated polio vaccine (tOPV; Sabin vaccine; Orimune), also provides protective immunity against paralytic poliomyelitis. In addition, oral polio vaccine uniquely protects against enteric infection by promoting mucosal immunity and offering the benefit of herd immunity by secondary immunization of susceptible persons exposed to asymptomatic shedding of vaccine strain virus from vaccine recipients. Unfortunately, as paralytic poliomyelitis due to wild-type virus was eradicated in the United States by effective immunization programs, the rare risk of paralytic poliomyelitis due to vaccine strain virus (3 to 12 cases annually) ultimately has become greater than the risk due to wild-type poliovirus. Therefore, only inactivated polio vaccine is used in the United States currently, whereas the effective, economically favorable, convenient trivalent oral polio vaccine continues to be used in wild-virus polio endemic regions in an attempt to eradicate paralytic poliomyelitis worldwide.

A vaccine containing DTaP, HBV, and IPV (Pediarix) has recently been licensed for use in the United States to provide the primary series of immunizations (first 3 doses) for children 6 months to 7 years old. This combination vaccine may be used for all 3 vaccine doses, or used to complete the primary series in infants who have already received 1 or 2 doses of DTaP, HBV, or IPV. The combination vaccine was developed to reduce the number of injections infants receive during routine childhood immunization, and provides the same vaccines that have previously existed individually (Infanrix, IPV, and Engerix-B).

Haemophilus influenzae type b (Hib) vaccine is a conjugated vaccine containing the Haemophilus influenzae type b capsular polysaccharide polyribosylribitol phosphate (PRP), which is the major virulence factor, conjugated with a carrier protein to enhance immunogenicity (7). Infants less than 6 weeks old should not be exposed to vaccines containing Haemophilus influenzae type b PRP antigen, as premature exposure may create immune tolerance, causing suboptimal antibody response upon subsequent antigen exposure and resulting in failure to develop protective antibody concentrations.

The four monovalent conjugated Haemophilus influenzae type b vaccines currently available are differentiated by their respective carrier proteins. Infants receive either a 2 dose or 3 dose series of Haemophilus influenzae type b vaccine during the first year of life (predicated by specific vaccine brand utilized), and a single booster dose between 12 months and 15 months of age (resulting in either a 3 dose or 4 dose regimen to completely immunize the child).

The number of conjugated Haemophilus influenzae type b vaccine doses required to immunize older children not receiving vaccine in infancy diminishes due to brisker antibody response seen when older children receive conjugated Haemophilus influenzae type b vaccine. If the first dose of vaccine is not administered until the child is between 7 months and 11 months of age, then only 3 doses are required to complete the regimen. If the first dose of vaccine is not administered until the child is between 12 months and 14 months of age, then only 2 doses are required to complete the regimen. If the first dose of vaccine is not administered until the child is between 15 months and 59 months of age, then only a single dose is required to complete the regimen. Non-immunized children 5 years old and older do not require Haemophilus influenzae type b vaccine unless they possess underling risk factors (impairment in immunity) that would increase their risk for invasive disease.

The most common adverse reactions to conjugated Haemophilus influenzae type b immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently.

Conjugated Streptococcus pneumoniae (PCV) vaccine is a conjugated heptavalent vaccine (Prevnar) containing the capsular polysaccharides of the 7 strains of Streptococcus pneumoniae responsible for 80% of all cases of invasive pneumococcal disease occurring in children in the United States (8). Each specific polysaccharide is conjugated with a nontoxic mutant diphtheria toxin to enhance immunogenicity when administered to infants. Capsular polysaccharide is an important virulence factor for Streptococcus pneumoniae, existing in antigenically distinct permutations that confer type specificity to the individual bacterium, and requiring a type-specific host immune response to protect against disease.

Nonconjugated pneumococcal polysaccharide vaccine (PPV), which was developed before conjugated pneumococcal vaccine, currently exists as a 23-valent vaccine (PNU-IMUNE 23 and Pneumovax 23) that protects against 85-90% of strains causing invasive disease occurring in children and adults in the United States, but is poorly immunogenic in children under 2 years of age. Use of nonconjugated polysaccharide vaccine is indicated for persons at least 2 years of age, and is administered as a single intramuscular injection. Persons at high risk for invasive pneumococcal disease (asplenia, sickling hemoglobinopathy, congenital and acquired immunodeficiency, immunosuppression, spinal fluid leak, chronic cardiac, pulmonary, hepatic, or renal disease) should receive a second dose of unconjugated pneumococcal polysaccharide vaccine, administered between 3 years and 5 years following the initial dose.

Infants receive a 4 dose regimen of conjugated pneumococcal vaccine. The primary series is administered by intramuscular injection at 2 months, 4 months, and 6 months of age, and a fourth (booster) dose is administered between the ages of 12 months and 15 months. The number of conjugated pneumococcal vaccine doses required to immunize older children not receiving vaccine in infancy is reduced due to the brisker antibody response seen when older children receive conjugated pneumococcal vaccine. If the first dose of vaccine is not administered until the child is between 7 months and 11 months of age, then only 3 doses are required to complete the regimen. If the first dose of vaccine is not administered until the child is between 12 months and 23 months of age, then only 2 doses are required to complete the regimen. Routine conjugated pneumococcal vaccination is not recommend for children who are 2 years or older, although children of this age group who are at high risk for invasive pneumococcal disease should be vaccinated with the nonconjugated 23-valent PPV.

The most common adverse reactions following conjugated Streptococcus pneumoniae immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently. Occasionally, fever may be high and local reactions severe, especially with subsequent doses of vaccine. Febrile seizures may complicate vaccine induced fevers.

Measles (Me) vaccine is an attenuated live virus vaccine that causes subclinical infection following administration, provoking a host immune response that protects against subsequent infection following exposure to wild-type virus. The first measles vaccine developed was a killed virus vaccine, which was associated with the potential development of an infection called "atypical measles" when vaccinated individuals were subsequently infected with wild-type virus. The current monovalent attenuated live virus vaccine (Attenuvax) contains the Moraten ("more attenuated") strain of measles virus, which effectively confers immunity while reducing the incidence of adverse events following vaccination (9).

Measles vaccine is most commonly administered in combination with mumps vaccine and rubella vaccine (MMR, mumps and rubella vaccines are also live attenuated virus vaccines), given as a subcutaneous injection to children between the ages of 12 months and 15 months of age. Approximately 95% of vaccine recipients respond to a single dose of vaccine; however, due to an increase in wild-type measles observed in vaccine recipients during the 1980s, current recommendations require a second dose of vaccine, generally administered between the ages of 4 years and 6 years prior to school entry (9).

The most common adverse reactions to MMR immunization are fever and local reactions at the injection site. Occasionally, transient rashes and transient thrombocytopenia may occur. Allergic reactions occur infrequently. Encephalitis has been suggested as an extremely rare complication of measles immunization, but definitive proof is lacking. No valid scientific evidence supports measles vaccine as causal causation for autism despite sensational claims to the contrary. Orchitis and parotitis have been rarely reported from mumps vaccine. Occasionally, transient arthralgia/arthritis and peripheral neuritis may occur from rubella vaccine (9).

Varicella (V) vaccine is an attenuated live virus vaccine that causes subclinical infection following administration, provoking a host immune response that protects against subsequent infection following exposure to wild-type virus. Oka strain varicella virus was initially developed in Japan. This strain was subsequently modified and is currently used in the United States. Varicella vaccine exists as monovalent vaccine (Varivax), which is administered as a single subcutaneous injection for children 12 months through 12 years of age, and as a two dose regimen separated by an interval of at least 4 weeks for children 13 years old and older. A single dose of varicella vaccine is associated with a 97% seroconversion rate in children <13 years old and a 94% seroconversion rate in older persons. A second dose of vaccine in associated with 99% seroconversion in adolescents and adults. Young children should routinely receive varicella vaccine as a component of universal childhood immunization, and older children and adolescent who have not had chickenpox should be identified and immunized (10,11).

The most common adverse reactions to varicella immunization are fever and local reactions at the injection site. Occasionally, recipients may have a localized (at the injection site) or more generalized varicella-like rash due to vaccine strain virus. A minority of vaccine recipients may have a mild case of chickenpox ("breakthrough chickenpox") due to wild-type virus following exposure to naturally occurring disease. Allergic reactions occur infrequently.

Hepatitis A virus (HAV) vaccine is a killed virus vaccine (12) containing formalin-inactivated hepatitis A virus that exists as monovalent vaccine and as bivalent vaccine in combination with hepatitis B vaccine (Twinrix). The first dose of vaccine produces protective antibody response within two weeks following administration. A second dose is administered to provide long term, durable protection against disease. The pediatric formulation of hepatitis A vaccine is indicated for use in the age group 2 years through 18 years. The initial dose is administered by intramuscular injection, followed by a second dose administered between 6 months and 12 months following the first.

Routine childhood immunization with hepatitis A vaccine is recommended for those regions and states where the incidence of hepatitis A infection is at least twice the national average, occurring at a frequency of at least 20 cases per 100,000 population annually. Eleven states surpass this threshold: Alaska, Arizona, California, Idaho, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Utah, and Washington. Childhood immunization with hepatitis A vaccine should be considered for those regions and states where the incidence of hepatitis A infection exceeds the national average and occurs at a frequency of between 10 and 20 cases per 100,000 population annually. Six states meet this criterion: Arkansas, Colorado, Missouri, Montana, Texas, and Wyoming. Hepatitis A immunization is also recommended for community control of recent outbreaks of infection, for travelers to hepatitis A endemic areas, for persons who have chronic liver disease, for homosexual and bisexual men, for injectors of illicit drugs, and for individuals with clotting factor disorders. The most common adverse reaction to hepatitis A immunization is a local reaction at the injection site. No serious adverse reaction is associated with hepatitis A vaccine.

Influenza vaccine is a vaccine that exists as an inactivated whole virus vaccine (not currently available in the United States) or as a split virus vaccine (subvirion vaccine; purified surface antigen vaccine) that contain the hemagglutinins of the predominately circulating strains of influenza virus. The vaccine traditionally contains antigens from two influenza A virus strains and one influenza B virus strain, determined by those most frequently isolated at the end of the current year's respiratory virus season and predicted to predominate in the next respiratory virus season. The vaccine is formulated and administered annually to compensate for antigenic shifts that occur in virus isolates in order to enhance strain-specific immunity during the current respiratory virus season. Those who should receive annual immunization include health care workers and others who may be significant vectors for contagion, healthy persons 50 years old or older, persons with underlying diseases (pulmonary, cardiac, metabolic, renal, and hemoglobinopathies), individuals receiving immunosuppression or chronic aspirin therapy, and pregnant women (beyond the first gestational trimester). Children between the ages of 6 months and 23 months should be immunized annually due to increased morbidity of influenza infection in this age group (13). Children younger than 9 years old receiving influenza vaccine for the first time should receive two doses of split virus vaccine administered in the age appropriate volume separated by at least a one month interval in order to enhance immunologic response and protection against infection.

In 2003, a live attenuated, cold-adapted trivalent viral influenza vaccine (FluMist) prepared by viral reassortment was approved for use in the United States. The vaccine exists as a spray for intranasal instillation, and contains the same three strains of influenza virus that are present in the current parenteral vaccine formulation. Use is limited to healthy individuals 5 to 49 years of age. Children 5 to 8 years old not previously immunized receive two doses of intranasal vaccine administered 60 days apart. Children 5 to 8 years old previously immunized with the intranasal vaccine, and all persons 9 to 49 years of age receive a single vaccine dose annually.

The most common adverse reactions to influenza immunization are fever and local reactions at the injection site. Allergic reactions occur infrequently. Guillain-Barre syndrome is a rare complication of influenza vaccination, apparently limited to adults.

Table 1: Recommended Childhood (Prior to School Entry) Immunization Schedule 2002 (1)
Vaccine (Route of Administration): Ages of Administration
HBV (IM): 0-1m, 1-4m, 6-18m
DTaP (IM): 2m, 4m, 6m, 15-18m, 4-6y
IPV (IM or SQ): 2m, 4m, 6-18m, 4-6y
Hib (IM): 2m, 4m, (6m), 12-15m
PCV (IM): 2m, 4m, 6m, 12-15m
MMR (SQ): 12-15m, 4-6y
Varicella (SQ): 12-15m
HAV (IM): 2-3y, 3-4y
Influenza (IM): 6-23m (annually)

Table 2: Recommended Childhood (Catch-Up) Immunization Schedule (12m-7y) 2002 (14)
Interval: Vaccines
0 (First visit): HBV, DTaP, MMR, Hib (12-60m)
1m: HBV, DTaP, IPV, Varicella
2m: DTaP, IPV, HiB (if first dose at 12-15m)
8m: HBV, DTaP, IPV
At age 4-6y: DTaP, IPV, MMR

Table 3: Recommended Childhood (Catch-Up) Immunization Schedule (7y-12y) 2002 (14)
Interval: Vaccines
0 (First visit): HBV, dT, MMR, IPV
2m: HBV, dT, MMR, IPV, Varicella (if susceptible)
8m: HBV, dT, IPV

Active immunization (as opposed to passive immunization) with vaccines provokes a host response that potentially confers durable immunity and protects against subsequent infection and disease following exposure to naturally occurring infection.

In the special circumstance of a susceptible person requiring immediate protection against disease, either prior to or following exposure to infection, transient immunity may be conferred by passive immunization, where preformed protective antibodies are administered. The advantages of passive immunization is the potential to provide immediate protection to the host. The major disadvantage of passive immunity is the subsequent decay of passively acquired antibody by metabolism and elimination, ultimately rendering the host potentially susceptible to infection once passively acquired antibody titers fall to subprotective concentrations.

Active immunization utilizes a live or killed antigen to stimulate the immune system to form an active immune response, while passive immunization is merely the injecting or infusing human or animal-derived antibodies into the body. Passive immunization preparations currently available include serum immunoglobulin, existing in formulations for intramuscular (IM-IG) and intravenous administration (IVIG), which can provide global protection against infections that are prevalent in the populations from whom these products are derived. In fact, this is why the administration of attenuated live virus vaccines (measles, mumps, rubella, varicella) is deferred for persons who have recently received blood products (including immunoglobulin preparations), since passively acquired antibody may prevent the vaccine-induced subclinical infection and the active immune response from developing. Killed virus, toxoid, conjugated polysaccharide, recombinant subunit, and bacterial antigen vaccines are not as adversely affected by the presence of passively acquired antibodies, and thus may be administered without consideration of blood products (including immunoglobulin preparations) recently received by the potential vaccine recipient.

Passive immunization products may also be specific for selected infections. These agents are labeled "hyperimmune" because effective concentrations of neutralizing antibody have been specifically ascertained. Those diseases for which passive immunity may be provided include respiratory syncytial virus (RSV-IG), palivizumab ("humanized" murine monoclonal anti-RSV antibody), hepatitis B (hepatitis B immune globulin, called HBIG), varicella (varicella zoster immune globulin; called VZIG), cytomegalovirus (cytomegalovirus immune globulin), and rabies (rabies immune globulin). Passive immunization products that protect against virulent toxins associated with infection are often called "antitoxin", and are administered to mitigate the significant systemic toxicity associated with infection. Tetanus immune globulin is derived from human serum. Botulism antitoxin (trivalent against botulism toxins A, B, and E) and diphtheria antitoxin are derived from horse serum (15).

Attenuated live virus vaccines (measles, mumps, rubella, varicella) should not be administered to persons who have impairment in immunity (congenital or acquired immunodeficiency, receiving immunosuppressive therapy, have malignancy or have undergone bone marrow or organ transplant) or are pregnant, due to the potential risk for the expected subclinical infection following immunization to become clinical, and potentially severe, posing risk to the vulnerable host or unborn child. Moreover, attenuated live virus vaccines should be administered simultaneously (during the same office visit), or individually separated by an interval of at least 4 weeks to prevent immunological interference with the second vaccine. Note specifically that attenuated live virus vaccines can be given simultaneously or at least 4 weeks apart, but at no time between these two time points. Additional doses of attenuated live virus vaccines in excess of those recommended for childhood immunization may be administered without increased risk of adverse reactions (16).

Noninfectious vaccines (killed virus, recombinant subunit, toxoid, conjugated polysaccharide, bacterial antigen) may be administered to persons who have impairment in immunity without increased risk, since these vaccines are incapable of causing infection. Immunologically impaired hosts may have suboptimal response to these vaccines, and may not be protected against subsequent development of disease following exposure. Noninfectious vaccines may be administered simultaneously or separated at any interval without appreciable risk of impaired immunologic response (16). Additional doses of these vaccines in excess of those recommended for childhood immunization are generally well tolerated, although the risk for enhanced systemic and local reactions may increase. Whole cell pertussis vaccine, diphtheria vaccine, and pneumococcal polysaccharide vaccine may be particularly prone to provoke exaggerated reactions with excessive doses of vaccine.

Vaccines are the single most cost-effective interventions performed to improve and maintain the health of citizens of the United States, and have been cited as one of the most significant advancements in medical practice occurring during the 20th century (17). Vaccines are not without risks, but the anxiety expressed by some parents is almost always the result of misperceptions fueled by misinformation. When considered against the risk of infection with concomitant associated morbidity and mortality, the benefits of universal childhood immunization far outweigh all risks for each of the vaccine-preventable diseases. In those circumstances where rare but potentially serious adverse reactions to immunization are demonstrated, such as the risk for intussusception following administration of the oral tetravalent rotavirus vaccine (18), the national Vaccine Adverse Event Reporting System (VAERS) provides identification of these rare complications and promotes the appropriate corrective actions. Health care providers should strongly endorse routine childhood immunization, and be capable and willing to adequately address any parental concerns.

Questions

1. Which of the following vaccines would be contraindicated in a 4 year old boy receiving immunosuppressive therapy for autoimmune hepatitis?
. . . . . a. Hepatitis A vaccine
. . . . . b. Hepatitis B vaccine
. . . . . c. Acellular pertussis vaccine
. . . . . d. Inactivated polio vaccine
. . . . . e. Varicella vaccine

2. Which vaccine should not be given to an 8 year old girl who has not been immunized previously?
. . . . . a. Hepatitis B vaccine
. . . . . b. Tetanus vaccine
. . . . . c. Acellular pertussis vaccine
. . . . . d. Inactivated polio vaccine
. . . . . e. Measles vaccine

3. Which parenteral vaccine should not be characterized as an attenuated live virus vaccine?
. . . . . a. Influenza vaccine
. . . . . b. Measles vaccine
. . . . . c. Mumps vaccine
. . . . . d. Rubella vaccine
. . . . . e. Varicella vaccine

4. Which passive or active immunization is specifically recommended for women in the second or third trimester of pregnancy?
. . . . . a. Respiratory syncytial virus immune globulin
. . . . . b. Cytomegalovirus immune globulin
. . . . . c. Rubella vaccine
. . . . . d. Influenza vaccine
. . . . . e. Varicella vaccine

5. Increased risk for intussusception was observed as a rare complication following immunization with which vaccine?
. . . . . a. Inactivated polio vaccine
. . . . . b. Oral polio vaccine
. . . . . c. Rotavirus vaccine
. . . . . d. Hepatitis A vaccine
. . . . . e. Hepatitis B vaccine

6. Indicate whether the follow are examples of active or passive immunity:
. . . . . a. palivizumab
. . . . . b. Diphtheria-Tetanus toxoid
. . . . . c. Diphtheria immune globulin
. . . . . d. MMR
. . . . . e. Influenza vaccine
. . . . . f. Botulism anti-toxin

References

1. Centers for Disease Control and Prevention. Recommended childhood immunization schedule --- United States, 2002. MMWR 2002;51:31-33.

2. Centers for Disease Control and Prevention. Hepatitis B virus: a comprehensive strategy for eliminating transmission in the United States through universal childhood immunization: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR 1991;40(RR-13):1-19.

3. Centers for Disease Control and Prevention. Diphtheria, tetanus, and pertussis: recommendations for vaccine use and other preventative measures --- recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR 1991;40(RR-10):1-28.

4. Centers for Disease Control and Prevention. Pertussis vaccination: use of acellular vaccine among infants and young children --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1997;46(RR-7):1-25.

5. Centers for Disease Control and Prevention. Notice to readers: Food and drug Administration approval of a fifth acellular pertussis vaccine for use among infants and young children --- United States, 2002. MMWR 2002;51:574.

6. Centers for Disease Control and Prevention. Poliomyelitis prevention in the United States: updated recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2000;49(RR-5):1-22.

7. Centers for Disease Control and Prevention. Recommendations for use of Haemophilus b conjugate vaccine and a combined diphtheria, tetanus, pertussis, and Haemophilus b vaccine: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1993;42(RR-13):1-21.

8. Centers for Disease Control and Prevention. Preventing pneumococcal disease among infants and young children: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2000;49(RR-9):1-38.

9. Centers for Disease Control and Prevention. Measles, mumps, and rubella --- vaccine use and strategies for elimination of measles, rubella, and congenital rubella syndrome and control of mumps: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1998;47(RR-8):1-57.

10. Centers for Disease Control and Prevention. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1996;45(RR-11):1-25.

11. Centers for Disease Control and Prevention. Prevention of varicella: updated recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1999;48(RR-6):1-5.

12. Centers for Disease Control and Prevention. Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1999;48(RR-12):1-37.

13. Centers for Disease Control and Prevention. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2002;51(RR-3):1-31.

14. American Academy of Pediatrics. Active Immunization. In: Pickering LK, et al (eds). 2000 Red Book: Report of the Committee on Infectious Diseases. 25th edition. 2000, Elk Grove Village, IL: American Academy of Pediatrics, pp. 6-41.

15. American Academy of Pediatrics. Passive Immunization. In: Pickering LK, et al (eds). 2000 Red Book: Report of the Committee on Infectious Diseases. 25th edition. 2000, Elk Grove Village, IL: American Academy of Pediatrics, pp. 41-53.

16. Centers for Disease Control and Prevention. General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP) and the American Academy of Family Physicians (AAFP). MMWR 2002;51(RR-2):1-36.

17. Centers for Disease Control and Prevention. Achievement in public health, 1900-1999 impact of vaccines universally recommended for children --- United States, 1990-1998. MMWR 1999;48:243-248.

18. Centers for Disease Control and Prevention. Intussusception among recipients of rotavirus vaccine --- United States, 1998-1999. MMWR 1999;48:577-581.

Answers to questions

1.e

2.c

3.a. It should be noted that the current parenteral influenza vaccine is not a live attenuated virus. However, a non-parenteral intranasal live attenuated influenza vaccine is available.

4.d

5.c

6a.passive.
6b.active.
6c.passive
6d.active
6e.active
6f.passive