Pediatric Examination and Board Review (165 page)

(A) oral polio vaccine (OPV) can cause vaccineassociated paralytic poliomyelitis (VAPP), and the risk is highest after the third dose of vaccine

(B) severe egg allergy (anaphylaxis) is a contraindication to poliovirus vaccine

(C) IPV is recommended for household contacts of patients with immunodeficiency disorders

(D) fever occurs in approximately 40% of infants who receive IPV vaccine

(E) OPV vaccine is preferred over IPV vaccine for routine immunization of infants in the United States

17.
A 2-month-old infant receives a dose of Hib conjugate vaccine as a component of the pentavalent DTaP-IPV/Hib vaccine. Then at 4 months he receives a different Hib conjugate vaccine, PRP-T (tetanus toxoid conjugate). The next dose should be administered at age

(A) 6 months

(B) 9 months

(C) 12 months

(D) 15 months

(E) 18 months

18.
Compared with natural infection with varicella, varicella vaccine is

(A) more likely to result in herpes zoster

(B) more likely to result in transmission of virus to contacts

(C) more likely to result in mild varicella disease if breakthrough varicella infection occurs

(D) more likely to result in the serious adverse event of encephalitis

(E) more likely to be associated with secondary bacterial infection

ANSWERS

1.
(A)
Minor illnesses (eg, upper respiratory infection or gastroenteritis, with or without fever) are not a contraindication to any of the routine childhood vaccines. A fever of 104.9°F (40.5°C) within 48 hours after previous immunization with a dose of diphtheria and tetanus toxoids and DTaP is considered a precaution, not a definite contraindication, to subsequent administration of DTaP vaccine. There are 4 true contraindications to immunizations: (1) previous anaphylactic reaction to an immunization, (2) encephalopathy within 7 days after a previous dose of DTP, DTaP, or Tdap, (3) severe immunocompromise (for live vaccines only), (4) pregnancy (live vaccines only). Mild illnesses or fever do not alter the safety profile or the immune response of a vaccine.

2.
(B)
The recommended interval to the second dose of vaccine is 2 months. However, for children 4 months to 6 years of age who start late or are more than 1 month behind, the minimum interval between doses 2 and 3 is 4 weeks for DTaP and IPV vaccines and 3 weeks for hepatitis B. The third dose of hepatitis B vaccine should be at least 16 weeks after the first dose.

3.
(E)
The Advisory Committee on Immunization Practices (ACIP) has now recommended routine influenza vaccine for all individuals older than 6 months of age. This is in part because hospitalization rates are highest for complicated influenza in the first 2 years of life (
Table 94-1
). Rates of hospitalization for these young subjects are comparable with adults older than 65 years of age. Decreasing influenza transmission among children has the potential to reduce spread among their household contacts and within the community. There are 2 types of influenza vaccine: LAIV (live attenuated) and TIV (trivalent inactivated); both vaccines contain egg protein. Children younger than 9 years of age receiving their first influenza vaccine require a second dose in 4 weeks. Contraindications for influenza immunization are allergy to any vaccine component, history of Guillain-Barré syndrome, and moderate or severe intercurrent illness.

TABLE 94-1
Estimated Rates of Influenza-Associated Hospitalizations/100,000 Persons

*
The low estimate is for infants 6-11 months, and the high estimate is for infants age 0-5 months.
Data from: Neuzil KM, Mellen BG, Wright PF, et al. Effect of influenza on hospitalizations, outpatient visits, and courses of antibiotics in children.
N Engl J Med.
2000;342:225.

4.
(E)
The 8-month-old child with HIV infection is too young to receive meningococcal vaccine. There are two meningococcal conjugate vaccines (MCV4) licensed for use in children. One manufactured by Sanofi Pasteur is approved for use in children 9 months of age and older. The other vaccine, manufactured by Novartis Vaccines and Diagnostics, is licensed for use in children as young as 2 years of age, although there is no current recommendation for the routine use of either vaccine in young children. The MCV4 vaccines are preferred over the unconjugated, older tetravalent polysaccharide vaccine, MPSV4. Health care providers should administer MCV4 to children ages 2-10 years (or 9 months to 10 years for the Sanofi vaccine) with persistent complement component deficiency, anatomic or functional asplenia, and other high-risk groups, including HIV. Any child previously immunized with MCV4 (at 9 months-6 years with the Sanofi version or at 2-6 years with the Novartis version) who remain at increased risk for disease will need to be re-immunized in 3 years. If the first dose of MCV4 is given after 7 years of age, the child will require a booster in 5 years. MCV4 is also recommended for routine immunization of all children 11-18 years of age and college freshmen living in dormitories.

5.
(C)
The newly licensed pneumococcal conjugate vaccine contains 13 serotypes that account for approximately 85% of the serotypes causing invasive pneumococcal infections (including bacteremia and meningitis) in children younger than 6 years of age in the United States. The 12-month-old infant should receive 2 doses of vaccine 6-8 weeks apart. The 7-year-old healthy child is too old for routine PCV-13 administration.

6.
(D)
Management of preterm infants lighter than 2000 g at birth if the mother is HBsAg positive should include HBIG within 12 hours after birth along with 4 doses of hepatitis B vaccine at 0, 1, 2-3, and 6-7 months of chronological age. The first dose of hepatitis B vaccine should be administered within 12 hours after birth. Recent recommendations are that the HBV series in infants born to HBsAg-positive mothers should be verified by serology (anti-HBs antibody). Some studies have demonstrated that a decreased seroconversion rate might occur among preterm infants lighter than 2000 g. By 1 month of chronological age, all preterm infants, regardless of weight, should respond serologically. If infants lighter than 2000 g at birth receive hepatitis B 1 at birth, this first dose should not be counted toward the completion of the 3-dose series; serologic conversion should be documented 1-2 months after series completion.

7.
(B)
In all states, including Oklahoma, routine immunization of children 1 year of age or older is now recommended. Postexposure prophylaxis with hepatitis A vaccine can be successful if the hepatitis A immunization is administered within 2 weeks of the exposure to hepatitis A–contaminated water or food. Routine hepatitis A immunization is not recommended for hospital personnel. Other high-risk groups for hepatitis A vaccine administration include men who have sex with men (MSM), intravenous drug abusers, people with chronic liver disease, family contacts of internationally adopted children, and “anyone for whom immunity is desired.”

8.
(C)
Tetanus immune globulin (TIG) should be administered if there is a history of less than 3 doses of tetanus toxoid administered or an unknown history, and there is not a clean minor wound. Clean minor wounds do not routinely require TIG. Other wounds such as those contaminated with dirt, puncture wounds, avulsions, penetrating wounds, burns, crush wounds, and frostbite require TIG. A dose of Td is indicated because when the status is unknown, it is reasonable to believe the child is one or more doses behind. There is no excess toxicity associated with an extra dose.

9.
(A)
There are 3 licensed acellular-pertussiscontaining vaccines available for use in the United States for children younger than age 7 in 7 different preparations or combination vaccines. There are also 2 acellular pertussis vaccines (Tdap) licensed and recommended for use in adolescents 11-12 years of age. There is no serologic correlate for the efficacy of pertussis vaccine. All of the licensed acellular pertussis vaccines contain pertussis toxoid, also termed
lymphocytosis promoting factor
(LPF).

10.
(C)
When administering DTaP vaccine to children who have previously received DT vaccine, the total number of doses of diphtheria and tetanus toxoids should not exceed 6 before the child reaches 7 years of age. Adolescents and adults should get Tdap vaccine with lower T and D content. Children with evolving neurologic disorders generally have pertussis vaccination deferred.

11.
(C)
For outbreak control of measles, monovalent vaccine can be administered to infants as young as 6 months of age. Because it is not available in the United States, MMR is usually substituted. Because of the substantial decrease in immunogenicity of measles vaccine given at 6 months of age, these infants should be reimmunized with MMR vaccine on schedule at 12-15 months of age and again at age 4-6 years.

12.
(E)
The usual dose of IGIV for treatment of Kawasaki disease is 2 g/kg. The administration of MMR vaccine should be deferred for 11 months after the administration of IGIV unless epidemic measles is occurring. Children with a history of egg allergy are at a low risk of anaphylactic reactions to MMR vaccine. Skin testing of children for egg allergy is not predictive of reactions to MMR vaccine. Most anaphylactic reactions are related to other vaccine components. Children with a history of anaphylactic reactions to gelatin or neomycin should only be vaccinated with MMR in settings where anaphylactic reactions can be properly managed. Children with HIV infection should receive MMR vaccine unless there is evidence of severe immunocompromise (CD4 percentage <15).

13.
(D)
Rubella vaccine is contraindicated during pregnancy. However, no cases of congenital rubella syndrome have occurred when susceptible women received rubella vaccine within 3 months of conception and delivered infants at term. There also has been no evidence of transmission of vaccine virus from immunized children to household contacts.

14.
(
C
) The clinical diagnosis of rubella is not reliable to determine if one is susceptible to rubella. Rubella immunity should be documented by serologic testing during pregnancy. For children who received a first dose of rubella vaccine, a second dose is not necessary but is given because of the recommendations for 2-dose routine measles immunization. The second dose of MMR vaccine can be given as early as 4 weeks after the first dose as long as the first dose is administered at or after the age of 12 months.

15.
(D)
The bites of squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, rabbits, and hares almost never require rabies postexposure prophylaxis. An exception for a rodent bite that does require prophylaxis is the bite of a woodchuck. All other animals listed in the answers require postexposure prophylaxis.

16.
(C)
The risk of VAPP is highest after the first dose of oral poliovirus vaccine, occurring in 1 in 700,000 recipients. OPV vaccine is contraindicated for household contacts of people with an immunodeficiency disorder because of the risk of spread of OPV to the affected person. OPV is no longer in use in the United States.

17.
(A)
The Hib component in the pentavalent vaccine is PRP-T. Therefore, the primary series for Hib can be completed by the third dose of Hib vaccine in either formulation at 6 months of age. A fourth dose of a Hib containing vaccine will be required at 12 months of age. PRP-OMP, the Hib vaccine contained in the combination PRP-OMP/hepatitis B vaccine has been unavailable in the United States although it remains licensed. For this Hib vaccine, the 6 month dose is not necessary.

18.
(C)
Varicella occurring in vaccine recipients is milder than in unimmunized children, with fewer vesicles, lower rates of fever, and more rapid recovery. Transmission of vaccines virus from one person to another is extremely rare.

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