Pediatric Immunization

1. PEDIATRIC IMMUNIZATIONS
BY
Minyahil Alebachew
Bpharm., MSc., Clinical Pharmacy
Mekelle University
Department of Pharmacy

2. Pediatric Immunizations
• Children are now routinely immunized against 13
infectious diseases.
• Immunization rates are at an all-time high in the
United States with >80% of children 3 years of age
receiving all the recommended vaccines.
• The need for timely immunization administration is
key to preventing disease resurgences.

3. Schedule for Immunizations
• The goal of pediatric immunization is to prevent
specific infectious diseases and their sequelae.
• For maximal effectiveness, a vaccine must be
administered to the susceptible population before
anyone has been exposed to the pathogen.

4. • The age at which immunizations are administered to
specific individuals depends, however, on several
factors
• age-specific risks of the disease,
• risks of complications,
• presence of maternal antibodies transferred through
the placenta,
• maturity of the immune system
– Usually, immunizations are administered at the youngest age
that the child is able to develop an adequate antibody
response.

5. Contraindications
• Acute, severe febrile illness;
• history of anaphylaxis to the vaccine or vaccine
components; and
• history of a severe reaction to an immunization are
clear contraindications to immunizations.
• Allergic reaction to previous exposure to vaccine
components,

6. • immunosuppression (e.g., immunosuppressive
therapy, immunodeficiencies),
• encephalopathy,
• recent administration of blood products, and
• pregnancy (although the risk in pregnancy is largely
theoretic) are contraindications to live-attenuated
virus or live-bacterial vaccines.

7. Adverse Effects
• Adverse reactions to inactivated vaccines include
pain at the injection site and fever within 48 to 72
hours of administration.
• Adverse effects from live-attenuated vaccines occur
7 to 10 days after immunization, after the virus has
replicated and the immune system has responded.

8. • Adverse reactions to live-attenuated vaccines
mimic the symptoms of disease.
– Transient rash occurs in 5% of patients receiving measles, mumps,
rubella (MMR) immunizations, and
– a mild varicella-like rash (median of five lesions) occurs in fewer
than 5% of patients receiving the varicella vaccine.
• Children with egg allergy can receive vaccines
produced in chick-embryo-fibroblast tissue culture
(e.g., MMR) because the risk for serious reaction to
these vaccines in egg-allergic children is very low.

9. Hepatitis B
• Children acquiring HBV infection before 5 years of
age are at an especially high risk of developing
chronic infection.
• All pregnant women should be tested for HBsAg and
infants born to HBsAg-positive mothers should
receive their first vaccine dose within 12 hours of
birth.

10. • Two hepatitis B (HepB) vaccines are currently available for
use in the United States.
• Recombivax-HB™ and Engerix-B™ are yeast-derived
recombinant vaccines administered as a three-dose series.
• Adolescents and adults also should follow a three-dose
schedule at 0, 1, and 6 months apart.
• PEDIARIX is a combination of DTaP, hepatitis B, and IPV.
• Monovalent vaccines are preferred for the initial
vaccination; however, combination vaccines can be used to
complete the series after 6 weeks of age.

11. Rotavirus
• Rotavirus is a major cause of gastroenteritis and subsequent
dehydration in children
• up to 50% of hospitalizations secondary to gastroenteritis in
children are caused by rotavirus infection.
• The American Academy of Pediatrics and CDC currently
recommend the routine immunization of infants with
RotaTeq, a live-attenuated, pentavalent oral vaccine against
rotavirus. (a three-dose series at 2, 4, and 6 months, with
the initial vaccination at 6 to 12 weeks of age and repeat
doses at 4- to 10-week intervals. )

12. Pertussis
• Pertussis (“whooping cough”), an infectious disease
caused by Bordetella pertussis, is characterized by a
paroxysmal cough with a whooplike, high-pitched
inspiratory noise, vomiting, and lymphocytosis.
• It is a highly communicable infection, which can
affect 90% of infants and young children in
nonimmunized households, and it can be associated
with serious sequelae, particularly in young infants.

13. • An estimated
– 0.3% to 14% of patients with pertussis experience
encephalopathy,
– 0.6% to 2% have permanent neurologic damage, and
– about 0.1 to 4% die.
• The efficacy of the DTP vaccines against pertussis after
primary immunization (three doses) is greater than 80%.
• Protection increases to 90% after the last booster (age 4–
6 years) and then decreases over the next 12 years, after
which protection is minimal.

14. • vaccines containing whole-cell pertussis have been
withdrawn and replaced with acellular pertussis b/c
the association of serious adverse events with
whole-cell pertussis vaccine
• Acetaminophen or ibuprofen should be
administered at regular intervals for 24 hours after
immunization to minimize the possibility of post
vaccination fever and pain associated with the local
reaction

15. Polio
• Polio,
– an infectious disease caused by a highly contagious
enterovirus,
– can strike at any age,
– but primarily affects children younger than 3 years of age
(>50% of cases).
• The three identified serotypes of poliovirus are
transmitted person to person by direct fecal–oral
contact or indirect exposure to infectious saliva, feces,
or contaminated water.

16. • Once established in the intestines, poliovirus can
enter the bloodstream and invade the CNS.
• As it multiplies, the virus destroys nerve cells, which
cannot be regenerated.
• As a result, muscles no longer function because of
the lack of electrical stimuli from affected nerve cells
and paralysis is permanent.

17. • The muscles of the legs are affected more often
than arm muscles; however, when trunk muscles
and muscles of the thorax and abdomen are
affected, quadriplegia can be the result.
• The polio virus also can attack the motor neurons
of the brainstem and, thereby, cause difficulty in
speaking, swallowing, and breathing.

18. • Immunity to polio can be achieved following natural
infection with poliovirus; however, infection by one
serotype of the poliovirus does not protect an individual
against infection from the other two serotypes.
• Immunity also can be achieved through immunization,
and the development of effective vaccines to prevent
paralytic polio was one of the major medical
breakthroughs of the 20th century.
– Since the advent of the trivalent OPV and IPV, the incidence of
paralytic poliomyelitis has been reduced dramatically.

19. • Until recently, the OPV or Sabin vaccine has been the
vaccine of choice WW.
• advantages of Sabin vaccine include
– low cost and ease of administration.
– induces lifelong immunity similar to that observed after
natural infection
– provides a high level of gut immunity, thus preventing the
carrier state
• Demerit of OPV
– the risk of vaccine-associated paralytic polio (VAPP),
especially after the first dose

20. • In contrast to OPV, the Salk vaccine (IPV) has not
been associated with VAPP or other reactions.
• Enhanced-potency IPV (IPOL, POLIOVAX), with an
improved immunogenic response
• IPV provides the same systemic immunity as OPV.
– IPV also induces some immunity of the gastrointestinal
tract mucosa, however, less than OPV.
– Intestinal immunity improves when two doses of OPV
follow the first two doses of IPV.

21. • Currently, OPV may be used only in special
circumstances, such as
– vaccination to control outbreaks of paralytic
polio,
– unvaccinated children traveling in <4 weeks to
areas endemic for polio, and
– children of parents who reject the number of
vaccine injections (these children should receive
IPV for the first two doses followed by OPV for
doses three and four).

22. • IPV is the only poliovirus vaccine that should be
used in
– patients with an immunodeficiency disorder,
– those receiving immunosuppressive chemotherapy, or
– children living with a person who is known or suspected to
have these conditions.
• For persons older than 18 years, IPV is the vaccine
of choice because it has not been associated with
VAPP and adults have a higher incidence of VAPP
than do children.

23. Haemophilus Influenzae Type b
• Haemophilus influenzae type b (Hib) was the most common
cause of bacterial meningitis and a leading cause of serious,
systemic bacterial diseases in children <5 years of age until an
effective vaccine was added to the routine immunization
schedule.
• The mortality rate associated with Hib meningitis was
approximately 5%, with neurologic sequelae observed in 25%
to 35% of survivors.

24. • Epiglottitis, cellulitis, septic arthritis, osteomyelitis,
pericarditis, and pneumonia also were commonly
caused by H. influenzae.
• Although H. influenzae is commonly associated with
otitis media and respiratory tract infections, type b
strains account for only 5% to 10%.

25. • The first Hib polysaccharide vaccine could elicit an
adequate immune response in children >2 years of
age;
 however, in children 18 to 23 months of age, the immune
response was only partial and a booster dose was required
at 24 months of age.
• The polysaccharide vaccine was replaced by
conjugate Hib vaccines to improve the immune
response in younger children.
• It has led to a 95% reduction in the incidence of Hib
disease in children <5 years of age.

26. Varicella Vaccine
• Varivax,
– a live attenuated vaccine against varicella-zoster
(chickenpox),
– is the first herpesvirus vaccine to be widely tested
in healthy and high-risk children and adults.

27. • The current immunization schedule recommends
administration of the first varicella vaccine dose at
12 to 15 months of age, followed by the second
dose at 4 to 6 years of age.
– For persons 7 to 13 years of age who have not received
varicella vaccine, two doses of varicella vaccine should
be administered at least 3 months apart.
– For persons >13 years of age, administer two doses of
varicella vaccine at least 4 weeks apart.

28. • If children are in need of their second dose of MMR
vaccine, the quadrivalent combination vaccine
ProQuad (MMRV) containing measles, mumps,
rubella, and varicella antigens,
– can be used because it can be interchanged with the single
entity vaccines.
• The most common adverse effect associated with
varicella vaccine administration is rash.

29. • Salicylates should not be used for 6 weeks after administration
of the varicella vaccine because of its association with Reye's
syndrome: nonsalicylate analgesics can be used.
• Although varicella vaccine might not entirely prevent the
occurrence of chickenpox in the immunocompromised patient,
it can modify the disease.
• Varicella vaccine is generally not recommended in children who
have cellular immunodeficiencies, but it can be used in those
with impaired humoral immunity.
• The vaccine should be avoided in children with
symptomatic HIV

30. • Varicella zoster immune globulin (VZIG) is recommended for
individuals at high risk for serious complications following
exposure to varicella.
– Those at risk include immunocompromised children or adults
• (e.g., acquired or congenital immunodeficiency, immunosuppressive therapy, cancer) and
premature infants <28 weeks' gestation or <1,000 g at birth.
– Pregnant women, who have not had chickenpox, are at high risk of severe
varicella complications
• (e.g., disseminated infection, pneumonia, death) and should receive VZIG within 72 hours of
exposure of varicella.
– Neonates born to women with symptoms of varicella within 5 days before, or
2 days after, delivery should receive VZIG regardless of whether the mother
received VZIG.

31. Measles/Mumps/Rubella
• The first dose of the MMR vaccine should be
administered in children 12 to 15 months of age,
and followed by a second dose of MMR at entrance
to grade school (age 4 to 6 years).
• The combination vaccine MMRV (ProQuad) should
be administered when both MMR and varicella
vaccinations are required.

32. • During an epidemic outbreak, infants can be
immunized at 6 to 9 months of age with single-
antigen measles, followed by a dose of MMR at 12
months of age, and a dose of MMR at 4 to 6 years of
age; older children should receive an additional
vaccine dose.
• Live-rubella virus vaccination is recommended for
all children at 12 to 15 months of age.

33. Tetanus Toxoid and Rabies Vaccine
• Tetanus (lockjaw)
– is a highly fatal,
– noncommunicable disease that is most notably manifested by
generalized, boardlike muscular rigidity.
– It results from wounds (including animal bites) infected by
Clostridium tetani, an anaerobic, gram-positive rod that exists in
nature as an extremely resistant spore.
– Prophylaxis can be achieved by actively stimulating antibody
formation against the toxin by immunization with Td. Passive
immunity can be achieved by administrating TIG.

34. Pneumococcus
• Streptococcus pneumoniae (pneumococcus) is responsible
for
– meningitis,
– pneumonia, and
– otitis media.
• Children <2 years of age and adults >65 years are at highest
risk for developing pneumococcal infections.

35. • The risk for disseminated pneumococcal infections is
increased by
• some underlying medical conditions (heart failure, chronic
obstructive pulmonary diseases),
• chronic liver disease (e.g., cirrhosis),
• functional or anatomic asplenia (e.g., sickle cell disease,
splenectomy), and
• acquired or inherited immunosuppressive conditions (e.g., HIV,
cancer, immunosuppressive therapy).
• S. pneumoniae is a common pathogen in children with HIV,
often presenting as one of the first manifestations of HIV
infection.

36. • Two pneumococcal vaccines are available:
• the original polysaccharide vaccine (Pneumovax) and
• the conjugate-pneumococcal vaccine (Prevnar).
• Pneumovax contains 23 purified capsular-
polysaccharide antigens of S. pneumoniae.
• Antibody response to the Pneumovax is
inconsistent in children <2 years of age, and the
antigens included in Pneumovax protect against
strains that typically cause adult disease.

37. • The ACIP recommends giving the conjugate vaccine
to all children <24 months of age to prevent invasive
pneumococcal disease (e.g., meningitis,
pneumonia); and to any child <5 years of age who is
at high risk of pneumococcal disease.
• The polysaccharide vaccine is recommended as a
supplement to the conjugate vaccine for some high-
risk children (e.g., sickle cell anemia).

38. • The conjugate pneumococcal vaccine (Prevnar)
improves immunogenicity and efficacy in infants
and toddlers.
This vaccine protects against the seven strains of
pneumococcus that cause 80% of all
pneumococcal invasive disease in children <6
years of age.

39. Hepatitis A
• Viral hepatitis can be caused by at least six
hepatotrophic viruses (identified by letters A
through G) and can present as either an acute or
chronic illness.
• Symptoms often include fever, malaise, anorexia,
nausea, abdominal discomfort, and jaundice.
• About one-third of hepatitis A cases occur in
children <5 years of age.

40. • The ACIP now recommends routine vaccination for
all persons >1 year of age.
• Vaccination programs targeting toddlers and young
children are important because children are often
asymptomatic and unwittingly transmit the virus to
adolescents and adults.
• Havrix and Vaqta, two hepatitis A vaccines with
adult and pediatric formulations, are indicated for
adults and children 1 year of age or older.

41. • Two doses are recommended, the second dose
should be administered 6 to 18 months after the
initial dose, depending on the formulation.
• The pediatric formulations of each product are
indicated for those 1 to 18 years of age and contain
half the antigen of adult formulations.
• Twinrix,
• a combination hepatitis A and B vaccine,
• is indicated in individuals >18 years of age on a three-
dose schedule.

42. Influenza
• The influenza vaccine is currently recommended for
anyone older than 6 months of age who is at
increased risk for complications secondary to
influenza.

43. • Target groups for the influenza vaccine include the
following:
• Any household contact or caregiver of high-risk individuals or
children <5 year of age
• People 50 or more years of age
• Residents of chronic care facilities
• Adults and children with chronic pulmonary or cardiovascular
disorders, diabetes mellitus, renal dysfunction,
hemoglobinopathies, or immunosuppression
• Children <18 years of age receiving aspirin therapy (because of
an increased risk of Reye's syndrome after influenza)

44. • Target groups for the influenza vaccine…
• Adults and children who have any condition
predisposing to respiratory complications, such
as aspiration
• Women who will be pregnant during the
influenza season
• Household members and care providers in
close contact with high-risk patients

45. • Influenza vaccine should be administered annually
for adequate protection.
• Children <9 years of age require two doses of the
vaccine administered 1 month apart to achieve
adequate antibody response.
If these children received influenza vaccination in a
previous season, however, only one dose is required.
• One dose of the vaccine is indicated for individuals
>9 years of age.

46. • Influenza vaccine contains a small amount of egg
protein and historically has been contraindicated in
patients with a severe egg allergy.
• A live, attenuated trivalent intranasal influenza
vaccine (FluMist) is available for use in healthy,
nonpregnant patients 5 to 49 years of age.
– After administration, recipients become infected with
attenuated virus strains, which stimulate both local IgA
and circulating IgG antibodies.

47. • Individuals should not receive the live vaccine
(FluMist) if any of the following apply:
• Age <5 years
• Moderate to severe illness
• Received another live vaccine within 4 weeks
• Severe allergy to eggs
• Currently taking salicylates
• Known or suspected immunodeficiency
• History of Guillain-Barré syndrome
• Asthma or reactive airway disease or other condition conferring
high risk of severe influenza

48. REFERENCES
1.Joseph T. Dipiro :Pharmacotherapy a
pathophysiologic approach(2008),7th edn.
McGraw-Hill Companies,New York.
2.Harrison’s: The principle of internal
medicine(2008),17th edn. McGraw-Hill
Companies,USA
3. Koda-Kimble: Applied Therapeutics: The
Clinical Use Of Drugs, 9th Edition
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