26.3 Immunization: RA 10152 and the National Immunization Program Schedule, Fully Immunized Child, School-Based Immunization, Other Recommended Vaccines, Vaccine Types, Cold Chain, Contraindications and AEFI

Why this area matters

The TOS asks you to prescribe the vaccines indicated at each age and apply well-child and preventive care. Philippine immunization coverage fell below target in recent years, and outbreaks of measles, diphtheria, pertussis and polio followed. In early 2025, partial data showed only about 61% of eligible children were fully immunized, against a 95% goal. Every visit, for any reason, is a chance to check and complete a child's vaccines and avoid "missed opportunities".

Statutory Framework: Republic Act No. 10152

Signed into law in 2011, Republic Act No. 10152 expanded the coverage of Presidential Decree No. 996 (the 1976 compulsory immunization decree) and mandated the provision of basic immunization services free of charge to all infants and children up to 5 years of age in all government hospitals, rural health units (RHUs), and barangay health centers. The Act expanded mandatory coverage to encompass:

1. Tuberculosis (BCG)
2. Hepatitis B
3. Diphtheria
4. Tetanus
5. Pertussis (Whooping Cough)
6. Poliomyelitis
7. Measles
8. Mumps
9. Rubella (German Measles)
10. Haemophilus influenzae type b (Hib)
11. Other vaccine-preventable diseases recommended by the Secretary of Health (such as Pneumococcal Conjugate Vaccine and Rotavirus Vaccine).

---

The Official Philippine DOH EPI Immunization Schedule

Every Filipino physician must memorize the precise timing, route, anatomical injection site, and minimum intervals governing the national immunization schedule.

The National EPI Schedule Table

Critical Clinical Details by Vaccine

1. Bacille Calmette-Guérin (BCG)

• Composition: Live attenuated strain of Mycobacterium bovis.
• Dose & Technique: Exactly 0.05 mL intradermally using a 26- or 27-gauge tuberculin syringe over the right deltoid insertion. An immediate pale, blanched wheal (6-8 mm diameter) must appear.
• Normal Reaction Timeline:
  • Immediate: pale blanched wheal that disappears within 30 minutes.
  • 2 to 3 weeks: small, red, tender indurated papule develops.
  • 4 to 6 weeks: papule ulcerates, secreting serous exudate.
  • 8 to 12 weeks: ulcer heals spontaneously, leaving a permanent, depressed, 4-7 mm scar.
• Counseling: Advise the caregiver never to squeeze the ulcer, apply alcohol, ointments, or compressive bandages.
• Adverse Reactions: Local abscess formation (if injected subcutaneously rather than intradermally) and regional suppurative lymphadenitis (BCGitis).

2. Hepatitis B Vaccine (Birth Dose)

• Composition: Recombinant hepatitis B surface antigen (HBsAg) produced in yeast cells.
• Window of Efficacy: Must be administered within the first 24 hours of birth. When an infant is born to an HBsAg-positive mother, administration of Hepatitis B vaccine plus Hepatitis B Immune Globulin (HBIG 0.5 mL IM) at separate anatomical sites within 12 hours reduces perinatal transmission from 90% to $< 5\%$.

3. Pentavalent Vaccine (DTwP-HepB-Hib)

• Composition: Diphtheria toxoid, Tetanus toxoid, whole-cell killed Bordetella pertussis (wP), recombinant HBsAg, and Haemophilus influenzae type b polyribosylribitol phosphate (PRP) capsular polysaccharide conjugated to tetanus toxoid.
• Administration: Three doses at 6, 10, and 14 weeks (minimum interval: 4 weeks). Whole-cell pertussis (wP) gives longer-lasting protection than acellular pertussis (aP) but causes more transient fever, local swelling and irritability.

4. Polio Vaccination: bOPV and IPV Dual Strategy

• Rationale for Dual Strategy: Bivalent Oral Polio Vaccine (bOPV: Sabin types 1 and 3) induces potent intestinal secretory IgA immunity that halts environmental fecal-oral transmission. Inactivated Polio Vaccine (IPV: Salk trivalent killed types 1, 2, and 3) induces systemic serum IgG antibodies, providing lifelong neuroprotection against all three serotypes without any risk of Vaccine-Associated Paralytic Poliomyelitis (VAPP) or circulating Vaccine-Derived Polioviruses (cVDPV).
• Schedule: Two doses of IPV are now standard in the Philippine EPI (administered at 14 weeks and 9 months).

5. Measles-Rubella (MR) and Measles-Mumps-Rubella (MMR)

• Timing: Dose 1 at 9 months and Dose 2 at 12 months (MMR in the current NIP; MR has also been used). Two doses before the first birthday are part of the definition of a fully immunized child.
• Why at 9 Months? Maternally transferred anti-measles IgG antibodies wane between 6 and 9 months. Vaccinating at 9 months seroconverts approximately 85% of infants; the second dose at 12 months seroconverts the remaining 15%, achieving $> 95-97\%$ population protection.

---

Biological Classification of Vaccines

Understanding the biological category determines handling requirements, immunologic mechanisms, and clinical contraindications.

---

Cold Chain Logistics and Vaccine Vial Monitors (VVM)

The cold chain is a temperature-controlled supply chain that ensures vaccine potency from manufacturer to the child's arm. Breaks in the cold chain result in permanent, irreversible loss of immunogenicity.

Temperature Storage Zones

• Refrigerator Compartment (+2°C to +8°C):
  • Required for all freeze-sensitive adsorbed vaccines: Pentavalent (DTP-HepB-Hib), PCV, Hepatitis B, IPV, and Td/TT.
  • Lyophilized vaccines with diluents: BCG (diluent must never be frozen; keep at $+2^\circ\text{C}$ to $+8^\circ\text{C}$).
  • Storage Rules: Vaccines must be placed on the central shelves, with spaces between boxes for air circulation. Never store vaccines in the door shelves (variable temperature) or directly against the rear cooling plate/evaporator.
• Freezer Range (-15°C to -25°C):
  • Used at national and regional stores for freeze-tolerant vaccines: OPV and lyophilized measles-containing vaccines. At health-facility level, these are usually kept at +2°C to +8°C with the other vaccines, while freeze-sensitive vaccines must never be frozen.

The Vaccine Vial Monitor (VVM)

A Vaccine Vial Monitor (VVM) is a heat-sensitive chemical indicator consisting of a square inside a darker circle, printed on the vaccine vial label. As the vial is exposed to cumulative ambient heat over time, the inner square darkens.

The Shake Test for Freeze Damage

Adsorbed vaccines (Pentavalent, Hepatitis B, PCV, Td) contain an aluminum adjuvant. Freezing causes the aluminum lattice to shatter and precipitate into large, heavy granules that rapidly fall out of suspension, destroying vaccine potency and increasing injection-site abscess formation.

• Shake Test Procedure:
  1. Take a vial from the suspected frozen batch and an intentionally frozen-and-thawed control vial of the same manufacturer and lot.
  2. Shake both vials vigorously for 10 to 15 seconds simultaneously.
  3. Place them side-by-side on a flat surface against a light background and observe the rate of sedimentation.
  4. Positive Result (Freeze Damaged): If the suspected vial sediments rapidly and forms a clear supernatant fluid faster than or at the same rate as the control vial, the vaccine has been frozen and must be discarded.
  5. Negative Result (Intact): If the suspected vial sediments very slowly and remains turbid and cloudy much longer than the control vial, the vaccine has not suffered freeze damage and is safe to use.

---

Contraindications vs. False Contraindications

In clinical practice and board examinations, distinguishing true contraindications from misconceptions is vital to prevent missed immunization opportunities.

True Absolute Contraindications

1. Severe Anaphylaxis: History of immediate, life-threatening anaphylactic reaction to a prior dose of the vaccine or an identical constituent (e.g., neomycin, gelatin, or yeast). Note: egg allergy is not a contraindication to MMR (MMR is grown in chick embryo fibroblast cultures, not egg albumen).
2. Encephalopathy within 7 Days of Pertussis Vaccine: Development of encephalopathy (coma, decreased consciousness, prolonged seizures) not attributable to another cause within 7 days of receiving DTwP or DTaP. Action: permanently discontinue the pertussis component; complete future vaccinations with DT or Td.
3. Severe Immunodeficiency for Live Vaccines: Congenital immunodeficiencies (SCID, agammaglobulinemia), leukemia, lymphoma, generalized malignancy, high-dose systemic immunosuppressive corticosteroid therapy ($> 2\text{ mg/kg/day}$ of prednisone for $> 14\text{ days}$), and symptomatic HIV infection with severe CD4+ T-lymphocyte suppression prohibit BCG, OPV, MR, MMR, Varicella, and Rotavirus.

Valid Reasons to Temporarily Defer

• Moderate to Severe Acute Febrile Illness: High fever or systemic prostration warrants deferral until acute illness resolves, to avoid confusing symptoms of the illness with vaccine adverse effects.

False Contraindications (DO NOT DEFER VACCINATION!)

---

Adverse Events Following Immunization (AEFI)

An Adverse Event Following Immunization (AEFI) is any untoward medical occurrence that follows immunization and does not necessarily have a causal relationship with the vaccine. The DOH Epidemiology Bureau manages national AEFI surveillance.

Classification of AEFI

1. Vaccine Product-Related Reaction: Caused by intrinsic biophysical properties of the vaccine (e.g., local injection-site soreness, low-grade fever after pertussis, transient rash 7-10 days after MMR).
2. Vaccine Quality Defect-Related Reaction: Caused by manufacturing defects (e.g., inadequate inactivation of endotoxin).
3. Immunization Error-Related (Programmatic) Reaction: Caused by improper handling, storage, reconstitution, or administration (e.g., sterile abscess from subcutaneous rather than intradermal BCG administration; bacterial sepsis from contaminated multidose vials).
4. Immunization Anxiety-Related Reaction: Arising from anxiety about the injection (e.g., vasovagal syncope, hyperventilation in adolescents).
5. Coincidental Event: Caused by an underlying condition that manifested coincidentally around the time of immunization.

Management of Post-Vaccination Anaphylaxis

• Sudden onset of stridor, wheezing, hypotension, generalized urticaria, or facial angioedema within 5 to 30 minutes of vaccination.
• First-Line Pharmacotherapy: Intramuscular Epinephrine (1:1,000 / 1 mg/mL) administered immediately into the anterolateral thigh.
  • Dose: 0.01 mg/kg (equivalent to 0.01 mL/kg of 1:1,000 solution; maximum single pediatric dose: 0.3 mg).
  • Repeat every 5 to 15 minutes PRN if symptoms persist.
  • Secondary agents: IV fluids for hypotension, nebulized albuterol for bronchospasm, and IV diphenhydramine/hydrocortisone as adjunctive therapy.

The fully immunized child and school-based immunization

• A fully immunized child (FIC) has received by 12 months of age:
  • one dose of BCG;
  • three doses of pentavalent vaccine;
  • three doses of oral polio vaccine;
  • two doses of a measles-containing vaccine.
  • The hepatitis B birth dose and IPV are also given.
• School-based immunization (DOH with DepEd):
  • measles-rubella (MR) and tetanus-diphtheria (Td) for Grade 1 and Grade 7 learners;
  • HPV vaccine for girls aged 9 to 14, usually in Grade 4.
• Supplemental immunization activities (mass campaigns) are held during outbreaks or to close immunity gaps, for example measles-rubella and polio campaigns.
• Catch-up rules:
  • never restart a series;
  • continue from where it stopped, respecting minimum ages and intervals;
  • two live injectable vaccines are given the same day or at least 4 weeks apart.

Other recommended vaccines

The Philippine Pediatric Society and the Pediatric Infectious Disease Society of the Philippines publish a yearly childhood immunization calendar. It includes vaccines given routinely in private practice beyond the NIP:

• rotavirus (oral, from 6 weeks; the series is completed by 8 months);
• influenza, yearly from 6 months, with two doses 4 weeks apart the first time for children under 9;
• varicella (from 12 months);
• hepatitis A (from 12 months);
• Japanese encephalitis (from 9 months);
• typhoid (conjugate vaccine from 6 months);
• meningococcal, HPV for boys and girls, and Tdap boosters.

Special groups (immunocompromised children, asplenia, travel) need additional or modified vaccines.