PREVENTIVE PEDIATRICS
Classification of prevention:
1.Primary: aims at preventing the occurrence of’ disease (e.g. by immunization).
2. Secondary: aims at early detection of a disease and stopping or reversing its progress 3. Tertiary: to stop the development of complications in a previously recognized disease.
Preventive pediatrics includes:
1. Prevention of genetic and congenital diseases: pre-marital counseling, prenatal detection of congenital anomalies and intra-uterine infections, etc.
2. Prevention of endocrine and metabolic disorders: e.g. neonatal screening tests for hypothyroid- ism and phenyl-ketonuria.
3. Prevention of nutritional disorders: e.g. early supplementation of iron and vitamin D to prevent iron deficiency and tickets.
4. Prevention of handicaps: e.g. antenatal and intrapartum care to prevent medical and physical handicaps (e.g. Erb’s palsy and mental handicaps), early detection of congenital
dislocation of hip, conductive deafness, refractive errors of vision, etc.
5. Prevention of accidents: more than 25% of infants’ accidents occur at home.
6. Prevention of psychiatric and emotional disorders.
7. Prevention of infectious diseases through 4 steps:
a)-Isolation of infected person from those at risk.
b)-Eradication of factors that transmit the infection. c)-Elimination of infective organism.
d)-Increasing the resistance of the host:
i- lmmunoprophylaxis.
ii- Antimicrobial prophylaxis.
IMMUNOPROPHYLAXIS
Types of immunity:
Immunity to an infectious disease can be achieved by different ways:
Passive immunity: a) Natural: transplacental antibodies.
b) Acquired: administration of antibodies (𝛄-globulins &
antitoxins)
Active immunity: a) Natural by acquiring the infection either in its subclinical or overt clinical forms. It may be life long as in measles, german measles, mumps, chicken pox, or transient as in common cold.
b) Acquired by administration of vaccines or toxoids.
I. NATURAL TRANSPLACENTAL PASSIVE IMMUNITY
• Maternal IgG antibodies actively cross the placenta mainly in latter half of last trimester.
• Preterm baby (less than 32 weeks’ gestation) is not fully protected.
• lgGs protect infant against diphtheria, poliomyelitis, measles, mumps, etc.
• Newborn is not protected from pertussis (its big lgM antibodies cannot cross placenta)
• Maternal antibodies disappear from infants' circulation by the 3rd-6th month of’ ages II. ACQUIRED PASSIVE IMMUNITY
Passive immunization by administration of exogenously produced antibodies
(immunoglobulins or antitoxins) is useful in the temporary prevention and treatment of certain infectious and diseases.
The agents used in passive immunization include:
• Standard human immune serum globulins (gamma globulins).
• Specific human immune serum globulins (e.g. for hepatitis B, rabies, etc)
• Animal serums and antitoxins (e.g. anti-snake serum, etc.) Most important indications for immune globulins and anti-toxins
1. Exposure to hepatitis A or B 2. Exposure to measles
5. Chickenpox in immunosuppressed children 6. Diphtheria
7. Snakes, scorpion and spider bites
Immunosuppressant therapy: - Anti-Rh (D) immunoglobulin to prevent Rh disease
III. ACTIVE IMMUNIZATION (VACCINATION)
The prevention of many previously fatal childhood diseases could be accomplishedthrough the use of routine active immunization (vaccination).
Definition: administration of vaccines or toxoids that stimulate the body’s immune system to pro-
duce antibodies and cellular immune responses that protect against the infectious agent.
Types of vaccines and toxoids:
1. Live attenuated viruses. e.g. measles, mumps, rubella, varicella, yellow fever, and oral polio (OPV or Sabin) vaccines.
2. Live attenuated strains of bacteria: e.g. BCG (bacille Calmette-Guerin) and oral Typhoid
vaccines.
3. Inactivated (killed) viruses.’ e.g. hepatitis B, hepatitis A, whole-virus Influenza, rabies, &
inactivated polio (IPV or Salk) vaccines.
4. Inactivated (killed) bacteria. e.g. pertussis, cholera & parenteral typhoid vaccine.
3.Inactivated purified immunological components of viruses or bacteria. e.g. split-virus influenza, pneumococcal polysaccharide, meningococcal polysaccharide, hemophilus influenzae type b (Hib conjugates) & acellular pertussis (aP) vaccines.
5. Vaccines produced by genetic engineering. Recombinant hepatitis B vaccine.
6. Toxoids. detoxified bacterial toxins still retaining their capacity to stimulate the Formation of antibodies (antitoxins), e.g. tetanus and diphtheria toxoids.
Other vaccines given for specific diseases:
• Typhoid-paratyphoid vaccine • Rabies vaccine
• Meningococcal polysaccharide vaccine • Influenza virus vaccine
• Pneumococcal polysaccharide vaccine • Cholera vaccine
• Hepatitis A vaccine • Varicella vaccine
Contraindications to live attenuated vaccines (oral polio, measles, mumps, rubella):
l. Immunodeficiency (except HIV infected infants who should be vaccinated for Measles, Mumps and Rubella + Inactivated polio vaccine [IPV] instead of live polio vaccine [OPV)).
2. Immunosuppressive therapy: vaccine is given 3 months after discontinuation of therapy.
3. Household contacts of immune deficient children should not receive oral polio vaccine.
4. Pregnant women should not receive live attenuated vaccines (except OPV & yellow fever).
Contraindications to pertussis vaccine:
1. Encephalopathy within 7 days of previous DPT vaccination.
2. Convulsions within 48 hours-72 hours of previous DPT vaccination.
3. Personal history of seizures that began recently or are poorly controlled.
4. Persistent unusual high-pitched cry (for > 3 hours) within 48 hours of DPT vaccination.
5. Fever >40.5 C unexplained by other cause within 48 hours of DPT vaccination.
6. Shock-like state or somnolence within 48 hours of DPT vaccination.
7. Allergic (anaphylactic) reaction to the vaccine.
In such cases we give DT (diphtheria + tetanus) vaccine instead of DPT vaccine.
Adverse reactions of some vaccines 1.
Measles and MMR vaccines:o Fever may develop between 6th-10th days after vaccination and lasts 1-2 days.
o Transient rash and arthralgia may develop.
2.
Pertussis vaccine: side effects occur from several hours to 72 hours of vaccination:o Redness, pain and swelling at injection site.
o Slight to moderate fever.
o Anorexia, drowsiness.
3.
BCG vaccine: contra-indicated in prematurity, malnutrition and infectious skin diseases.o Persistent ulcer at the site of vaccination o Regional suppurative lymphadenitis,
o Marked lymphadenitis with cold abscess and tuberculous sinus, and
o Generalized B.C.G. infection especially in immunodeficient infants.
Although BCG gives only partial immunity, it is valuable in the
prevention of hematogenous spread of tubercle bacilli and development of fatal miliary TB.
4.
Poliomyelitis vaccines:Oral poliovirus vaccine “Sabin vaccine”: Live attenuated trivalent vaccine Advantages: l. Ease of administration
2. Easy spread of attenuated virus from the stools of vaccinated babies to his surrounding community leading to "2ry
vaccination" of the community.
Disadvantages:
1. Needs proper refrigeration (Cold chain from manufacturer to consumer)
2. Infection with other enteroviruses can interfere with its effectiveness.
3. Contraindicated in altered immunity states (see above) 4. Breast milk may contain specific circulating antibodies,
which may interfere with oral polio vaccine.
Therefore, it is recommended to avoid putting the infant to the breast an hour or more before and after giving the oral polio vaccine. The baby may spit or vomit the vaccine.
Inactivated trivalent poliovirus vaccine “Salk vaccine”
Advantages: l. Effective in prevention of the disease in the vaccinated child.
2. Can be administered to immune deficient children 3. Easier to preserve and transport.
Disadvantages: 1. Has to be injected, thus difficult in mass vaccination.
2.
Killed virus is NOT excreted in stools, so No 2ry vaccination of community.3.
Does not give good gastrointestinal immunity, so, immunized persons can still transmit the virulent poliovirus in their stools.Old chain in transportation & storage of vaccines
1. Cold chain: vaccines should always be kept refrigerated between 0 &
+80C during transportation, distribution and storage. Oral polio vaccine is stored freezed at —200C.
2. Vaccine diluent should also be kept refrigerated (0 to +80C).
3. Oral polio vaccine vial is kept on top shelf of refrigerator under the freezer.
4. Measles vaccines are kept on top shelf of refrigerator under the freezer.
5. BCG, DPT, DPTS, DT and IT are kept on the rd shelfofthe refrigerator.
6. Freezing damages, the killed vaccines & toxoids (DPT, DPTS, DT, and IT).
7. Disinfectants & antiseptics (as alcohol & detergents) can damage the vaccines.
8. Heat and direct sunlight destroy the vaccines.
9. Cold chain monitors should be used to ensure that the cold chain has not been broken during the transportation or storage of vaccine.
10. During the vaccination session, vaccines are kept in a cup containing ice.
11. Any vaccine remained in opened vials after the vaccination session should be discarded.