Pentavalent Vaccine
Definition And Composition
- Combination vaccine containing multiple immunogens physically combined in single preparation.
- Incorporates Diphtheria, Tetanus, Whole-cell Pertussis (DTwP), Hepatitis B, and Haemophilus influenzae type b (Hib).
- Antigens adsorbed onto insoluble aluminum salts acting as adjuvants.
- Available brands include Pentavac PFS, Comvac-5, ComBE Five, Shan-5, and Easyfive-TT.
Antigenic Content Matrix
| Antigen Component | Concentration/Dose |
|---|---|
| Diphtheria toxoid | ≥20 to ≤30 Limit of flocculation |
| Tetanus toxoid | ≥2.5 to ≤25 Limit of flocculation |
| Whole-cell Pertussis | ≥4 International Units |
| Haemophilus influenzae type b (PRP conjugate) | 10 Micrograms |
| Hepatitis B surface antigen | 10 Micrograms |
Advantages And Public Health Impact
- Reduces number of injections administered during single visit.
- Decreases required office visits and potential administrative costs.
- Simplifies packaging, storage, and transportation.
- Enhances overall immunization coverage.
- Replaced standard DPT vaccine to improve Haemophilus influenzae type b vaccination rates.
- Significantly reduced Haemophilus influenzae type b meningitis cases following Universal Immunization Program introduction.
Administration Details
- Dose measures exactly 0.5 milliliters.
- Administered strictly intramuscularly.
- Preferred site remains anterolateral aspect of mid-thigh.
Storage And Cold Chain Requirements
- Requires strict storage at 2 to 8 degrees Celsius.
- Classified as freeze-sensitive vaccine due to adsorbed aluminum adjuvants.
- Accidental freezing mandates immediate discarding.
- Shake test detects erroneous freezing.
- Stored in middle shelves of ice-lined refrigerators.
Immunization Schedule
- Introduced into Universal Immunization Program in phased manner since 2011.
- Administered primarily at 6, 10, and 14 weeks of age.
- First dose acts as priming dose despite maternal antibodies.
- Permitted for administration up to 1 year of age.
- Induces excellent immunity lasting till second year of life.
- Booster dose at 15 to 18 months utilizes DTwP and Haemophilus influenzae type b combination.
Adverse Effects And Precautions
- Minor events include local pain, swelling, redness, fever, fussiness, anorexia, and vomiting.
- Reactions predominantly attributed to whole-cell pertussis component.
- Postmarketing surveillance confirmed no causal link to severe adverse events or deaths.
- Absolute contraindication involves severe allergic reaction or anaphylaxis to previous dose or vaccine component.