Child Vaccination: A Comprehensive Guide

I. Understanding Immunity

Immunity is the body’s ability to resist disease.

1. Types of Immunity Based on Specificity

• Non-specific immunity: This is the body’s general defense against all pathogens, including:

• Physical barriers: Skin, mucous membranes.

• Chemical barriers: pH levels, secretions, lysozyme.

• Microbial barriers: Gut microbiota, respiratory tract microbiota.

• Specific immunity: This involves the body’s ability to recognize, destroy, and remember specific pathogens. It consists of three main mechanisms:

• Humoral immunity: Mediated by antibodies (IgG, IgM, IgA, IgE, IgD) produced by B cells.

• Cell-mediated immunity: Mediated by T cells (T helper, T cytotoxic) that attack and destroy infected cells.

2. Types of Immunity Based on Origin

• Active immunity: This is immunity acquired through the body’s own production of antibodies after exposure to an antigen.

• Natural active immunity: Acquired through natural infection.

• Artificial active immunity: Acquired through vaccination.

• Passive immunity: This is immunity acquired through the transfer of antibodies from another source, without the body’s own production.

• Natural passive immunity: Acquired through maternal antibodies passed to the baby via the placenta or breast milk.

• Artificial passive immunity: Acquired through the injection of antibodies.

II. Immune Response to Vaccines

• Step 1: Primary Response: This is the initial immune response when the body first encounters a vaccine.

• A minimum of 4 days is needed to produce enough protective antibodies.

• Step 2: Secondary Response: This is the immune response upon subsequent exposure to the same antigen.

• It’s generally advised not to administer two live vaccines simultaneously.

• A minimum of 4 weeks should be between live vaccines.

• If a live vaccine is administered before or after IgG injection, the immune response might be weakened (this doesn’t affect killed vaccines).

III. Types of Vaccines

1. Live-attenuated viral vaccines:

• Measles, mumps, rubella, chickenpox, smallpox, rotavirus, oral polio, yellow fever, nasal flu vaccine.

2. Live-attenuated bacterial vaccines:

• Tuberculosis, oral typhoid.

3. Whole-cell inactivated vaccines:

• Polio, injectable typhoid, hepatitis A, rabies, influenza, pertussis, cholera, plague.

4. Acellular inactivated vaccines:

• Diphtheria, acellular pertussis, tetanus, hepatitis B, influenza, HPV, anthrax, Lyme, pneumococcal, meningococcal, typhoid VI.

IV. Indications and Contraindications for Vaccination

1. Children 1 month of age and older:

• Temporary deferral outside the hospital:

• Premature infants weighing less than 2000g.

• Children with progressively worsening reactions after previous vaccinations.

• Temporary deferral in the hospital:

• Children with malnutrition or chronic illness.

• Children with heart failure or pulmonary hypertension >= 40mmHg.

2. Newborns:

• Temporary deferral outside the hospital:

• Premature infants weighing less than 2000g.

• Premature infants born before 34 weeks:

• For mothers HBsAg (-), hepatitis B vaccination is deferred until reaching 34 weeks. For mothers HBsAg (+), consult a doctor and vaccinate at the hospital.

• BCG vaccination is deferred until reaching 34 weeks.

• Temporary deferral in the hospital:

• Premature infants born before 28 weeks: Hepatitis B vaccination is administered when reaching 28 weeks.

• Premature infants born before 34 weeks: BCG vaccination is administered when reaching 34 weeks.

V. Vaccine Storage and Usage

• Store vaccines at 2-8°C.

• After vaccination, take the child to a medical facility if any of these symptoms occur:

• Difficulty breathing, restlessness, lethargy, refusal to feed, excessive crying.

• High fever that is difficult to control or persists for >= 24 hours.

• Petechiae (small purple spots).

• A rash that spreads rapidly within 24-48 hours after vaccination.

VI. Catch-up Vaccination for Children Who Missed Vaccinations

• Hepatitis B:

• Dose 1: Immediately after the contraindication is resolved.

• Dose 2: 1 month after dose 1.

• Dose 3: 4-12 months after dose 2.

• Diphtheria, pertussis, tetanus:

• Under 6 months:

• 3 consecutive doses given 1-2 months apart.

• Dose 4 at 15-18 months.

• Dose 5 at 4-6 years old.

• 6 months – 5 years:

• 3 consecutive doses given 2 months apart.

• Dose 4: 6-12 months.

• Dose 5: 4-6 years if dose 4 was administered before 4 years.

VII. Comparison of Live-attenuated and Killed Vaccines

• Live-attenuated vaccines:

• Must be artificially cultured.

• Typically administered in a single dose.

• Elicit an immune response similar to natural infection.

• Affected by antibodies in the blood.

• May cause serious, adverse reactions.

• More prone to spoilage.

• Killed vaccines:

• Cannot be recreated or replicated.

• Typically require 3-5 doses. Antibody levels gradually decline over time.

• Primarily induce humoral immunity.

• Less affected by antibodies in the blood.

• Less likely to cause serious, adverse reactions.

• Easier to store.

Note:

• This information is intended for informational purposes only and should not be considered a substitute for professional medical advice.

• Consult a healthcare professional for personalized vaccination recommendations for your child.

• Vaccinating your child according to the national vaccination schedule is essential for protecting their health.

Wishing your little ones good health and happiness!