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Review of childhood and Adolescent Vaccination 2010. Marie-Denise Gervais, M.D. Department of Family Medicine and Community Health University of Miami, Miller School of Medicine. Childhood Vaccination.
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Review of childhood and Adolescent Vaccination 2010 Marie-Denise Gervais, M.D. Department of Family Medicine and Community Health University of Miami, Miller School of Medicine
Childhood Vaccination The impact of routine vaccination on childhood diseases in U.S. is considered one of the major medical achievements of the 20th century…
Trends in Deaths Causedby Infectious Disease (US) 900 800 65 60 700 55 50 600 45 40 500 Mortality Rates per100,000 US Population 35 30 400 25 1980 1984 1988 1992 300 1982 1986 1990 1994 200 100 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Centers for Disease Control and Prevention. US Dept of Health and Human Services, 1998.
Vaccine Development Disease Year Disease Year Smallpox Rabies Typhoid Cholera Plague Diphtheria Pertussis Tetanus Tuberculosis Influenza Yellow fever Poliomyelitis Measles 1798 1885 1896 1896 1897 1923 1926 1927 1927 1945 1953 1955 1963 Mumps Rubella Anthrax Meningitis Pneumonia Adenovirus Hepatitis B HaemophilusInfluenzae type b Hepatitis A Varicella Lyme disease Rotavirus 1967 1969 1970 1975 1977 1980 1981 1985 1995 1995 1998 1998 MMWR Morb Mortal Wkly Rep. 1999;48(12):243-248.
Morbidity Pre- and Post-Vaccinations (US) Annual MorbidityPrior to Vaccine* Morbidity1998 % Decrease Disease Smallpox Diphtheria Pertussis(paralytic) Tetanus Poliomyelitis Measles Mumps Rubella HaemophilusInfluenzae type b 48,164 175,885 147,271 1,314 16,316 503,282 152,209 47,745 20,000 0 1 6,279 34 0 89 606 345 54 100% >99.9% 95.7% 97.4% 100% >99.9% 99.6% 99.3% 99.7% MMWR Morb Mortal Wkly Rep. 1999;48(12):243-248.
Active immunity • Stimulation of immune system to produce Ag-specific humoral(Ab) and cellular immunity through : • Natural disease : immunity is long through immunologic memory • Vaccination : similar memory without the risk of disease
Live attenuated Must replicate to be effective Usually effective with 1 dose Severe reactions possible Interference with circular Ab MMR, Varicella,nasal Flu, OPV Inactivated Heat / Formalin Cannot replicate Requires 3-5 doses Immune response mostly humoral Ab titer falls overtime Principal Ag may not be defined (hib) IPV,DTaP, Hep B,A Classification of vaccines
Pertussis • Most hospitalizations and complications occur in infants • 1/2 cases occur in infants, 3/4 in children ≤ 5y/o • Complication: pneumonia*(15%), seizures(2.2%) , encephalopathy (0.7%) and permanent brain damage • Source: respiratory droplets from adults and adolescents • Highly contagious
Pertussis cont’d • Contagiosity is long (7days post exposure to 3 weeks after symptoms onset) • Incubation: 5 to 21 days (7-10) • Immunity is lifelong • Transplacental immunity wanes rapidly after birth • Recent outbreaks in US since 1990’s
Pertussis vaccine • DTP 70% to 90% effective. • DTP adverse reactions: persistent crying, unusual high-pitched cry, seizures, hypotonic-hyporesponsive episodes. • Protection wanes with time ≤ 12 years. • DTaP has1/4 to 1/2 the adverse reactions. • DTaP not recommended after age 7. • 2006: Tdap adolescent prep 11-12 y/o.
Tetanus and Diphteria • Hundreds of thousands of tetanus deaths worldwide • Only 26 cases of Tetanus in 2000 in US • Spasms of jaw muscles( trismus) and back muscles(opisthotonos). • In the 1920’s, 14,000 deaths/year to diphteria • Only 2 cases of diphteria in 2000 in US • Tonsillitis, myocarditis, heart failure and neuritis
Td / Tdap • Tdap recommended for 1st booster dose then Td every 10 years for persons ≥ 12 y/o. • Contains same quantity of tetanus toxoid as DTP , DTap and DT. • Contains only 1/11 as much diphteria toxoid. • Arthrus-type hypersensitivity reaction or fever ≥ 103ºF should not receive Td more often than every 10 years.
Haemophilus Influenzae type B • Most common cause of bacterial meningitis in children≤5 y/o. • Peak incidence 6- 12 months of age. • Meningitis has 2%-5% mortality rate even with appropriate treatment • Neurologic sequelae in 30% of survivors • Epiglottitis, facial, orbital and periorbital cellulitis, pneumonia, osteomyelitis,septic arthritis and pericarditis.
Hib vaccine • Hib organism is encapsulated in polysaccharide capsule. • Unencapsulated H-flu colonize the respiratory tract (sinusitis, otitis media, bronchitis). • Vaccines against Hib do not protect against other strains of Hflu. • Immature immune systems of infants do not respond to polysaccharide Ag • Ag of Hib capsule is linked to other proteins (diphteria, tetanus, meningococcal) to improve recognition.
Hib vaccine (cont’d) • Hib not given before 6 weeks of age (may induce tolerance to Ag) • Efficacy 95% to 100 % • Also decreases nasopharyngial carriage • Unimmunized children acquire natural immunity by age 5. • No serious adverse reactions.
Poliomyelitis • 18,000 paralytic cases in 1954 in US. • Last case of indigenous polio : 1979 US, 1994 Peru. • Recent outbreak in D.R and Haiti due to a revertant virus. • Enterovirus, 3 serotypes, feco-oral route,75% to 95% transmission in household contacts. • Subclinical infection(95%), non specific viral illness(5%), nonparalytic meningitis, paralysis.
IPV-Salk (inactivated) Cannot cause VAPP Safe for immunocompromized IM injection Less GI immunity OPV (attenuated) Easier administration Cohort effect Can revert and cause VAPP ( 1 case per 2.4 million doses of OPV.) No longer recommended in US Polio Vaccines
MMR • Combination of 3 live attenuated vaccines • Contains neomycin, gelatin, sorbitol, human albumin, and is produced in chick cells. • Maternal Ig persist until 9-11 months. • 1st dose is recommended at 12-15 months. • Ab persist ≥ 17 years (life!) • Adverse reactions: pain ,irritation, redness. • Specific delayed reactions: • Measles..fever and rash. • Mumps…transient orchitis • Rubella…lymphadenopathy and arthralgia.
Hepatitis B • 128,000 to 320,000 infected annually in U.S. • HBV infection more likely to become chronic when acquired early in life: • 90% as infants • 30% to 60% if less than 4 y/o • 5% to 10% as adults • 36% of all HBV infection contracted the infection in childhood • HBV is the 2nd cause of cancer worldwide
Rationale for HepB vaccination • HBV infection high morbidity and mortality. • HBV infection from child to child reported in schools, daycare centers, families. • No risk factor was identified in 30% of infected persons. • Cost effectiveness of vaccine. • Protective Ab levels ( ≥ 10mIU) in 95% of children. • Standing orders for Hep B vaccines at birth.
Streptococcus Pneumoniae • Encapsulated organism, 90 serotypes • Most common bacterial cause of meningitis*, bacteremia, pneumonia, otitis media in US • Incidence highest in infants then declines with age and increases in the elderly • Risk factors; age, race, recent use of Abx, daycare, exposure to tobacco smoke, chronic medical conditions; sickle-cell and HIV
Pneumococcal conjugate vaccines • 3 vaccines are available : • Pneumovax, 23-valent, polyssacharide . • Prevnar, 7-valent,conjucated. - (new) Prevnar,13-valent, conjugated. • Pneumovax ( only stimulates B lymphocytes) not effective in children ≤ 2y/o. • Prevnar elicits T-dependant immune response. • $108 per dose… most expensive routine infant immunization series to date. • No serious adverse reaction with Prevnar.
Varicella • 4 millions cases of VZV infection per year in US. • Hospitalization rate: 5/1000 cases. • Death rate: 0.7/100,000 cases. • Secondary attack rates: 90%. • Complications: Impetigo , pneumonia , ataxia , encephalomeningitis, glomerulonephritis … • Most severe in neonates and adults.
Varicella vaccine • Live attenuated virus • 97% effective against severe disease • 85% protective for any infection; for ≥ 7years • Less immunogenic in older children • Ab levels have persisted 20 y in Japan • Adverse reaction 25% after 1st dose, 47% after 2nd dose • Possible postexposure prophylaxis
2005-10 New Vaccines • Rota Teq: live oral rotavirus; 2- 4- 6m. • ProQuad: MMRV • Hepatitis A: Havrix; 2 doses 6 months apart after 1 year. • Influenza: expanded indication 6- 59 m (23) • Meningococcal MCV4 age 11-12y/o • Pediarix: (DTaP+ IPV+ HepB) • HPV *:3 doses after age 9 (0,2,6m)