Usage
This combination vaccine is prescribed for active immunization against diphtheria, tetanus, pertussis (whooping cough), hepatitis B, and invasive disease caused by Haemophilus influenzae type b (Hib). It is intended for use in infants and young children.
Pharmacological Classification: Vaccine (combined hexavalent vaccine)
Mechanism of Action: This vaccine stimulates the immune system to produce antibodies against the included toxoids and antigens. The antibodies provide active immunity against the targeted diseases.
Alternate Names
DTaP-HB-IPV-Hib, DTaP-IPV-Hib-HepB, hexavalent vaccine. Brand names may include Infanrix hexa, Vaxelis, and Hexacima (among others depending on region).
How It Works
Pharmacodynamics: The vaccine components induce an immune response by mimicking the natural infection without causing the actual disease. This leads to the production of specific antibodies that neutralize the toxins produced by diphtheria, tetanus, and pertussis bacteria, as well as the surface antigens of hepatitis B and Hib.
Pharmacokinetics: The toxoids and antigens in the vaccine are administered intramuscularly. The absorption, distribution, metabolism, and elimination of the individual components may vary. The conjugated Hib component enhances the immune response in young children.
Mode of Action: The diphtheria and tetanus toxoids are inactivated toxins that retain their immunogenicity. The acellular pertussis component contains purified antigens from Bordetella pertussis. The hepatitis B component contains recombinant hepatitis B surface antigen (HBsAg). The Hib component is a capsular polysaccharide conjugated to a protein carrier (e.g., tetanus toxoid). These components stimulate B lymphocytes to produce antibodies.
Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: The vaccine’s primary mechanism involves antibody production through B cell activation. The toxoids and antigens do not directly interact with receptors, enzymes, or neurotransmitters in the same way that drugs do.
Dosage
Standard Dosage
Infants and Children (6 weeks through 4 years):
- A three-dose primary series of 0.5 mL intramuscular injections is given at 2, 4, and 6 months of age.
- The first dose may be administered as early as 6 weeks.
- A booster dose is recommended 6 to 12 months after the last primary dose, typically during the second year of life.
Special Cases:
- Premature infants: The decision to administer the vaccine to premature infants should be made on a case-by-case basis, considering the infant’s medical history and the risk of apnea.
Clinical Use Cases
The vaccine is administered intramuscularly, ideally in the anterolateral thigh for infants and young children, and the deltoid muscle for older children. It is not for intravenous, intradermal, or subcutaneous administration. There are no specific dosage recommendations for clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Side Effects
Common Side Effects:
- Pain, redness, and swelling at the injection site
- Fever
- Irritability, drowsiness, or fussiness
- Loss of appetite
- Vomiting or diarrhea
Rare but Serious Side Effects:
- Seizures (febrile or non-febrile)
- Hypotonic-hyporesponsive episode (HHE)
- Allergic reactions (e.g., anaphylaxis)
- Encephalopathy
Contraindications
- Severe allergic reaction (anaphylaxis) to a previous dose or any vaccine component
- Encephalopathy within seven days of a previous dose of pertussis-containing vaccine
- Progressive neurological disorder (until stabilized)
Drug Interactions
- Immunosuppressive therapies (e.g., corticosteroids, chemotherapy) may reduce the immune response.
- Concomitant administration of anticoagulants requires caution due to the risk of bleeding at the injection site.
Pregnancy and Breastfeeding
This vaccine is not indicated for use in pregnant or breastfeeding women. It is only intended for infants and young children.
Drug Profile Summary
- Mechanism of Action: Stimulates antibody production against diphtheria, tetanus, pertussis, hepatitis B, and Hib.
- Side Effects: Common: local reactions, fever, irritability. Rare but serious: seizures, HHE, allergic reactions, encephalopathy.
- Contraindications: Previous severe allergic reaction, encephalopathy following pertussis-containing vaccine, progressive neurological disorder.
- Drug Interactions: Immunosuppressants, anticoagulants.
- Pregnancy & Breastfeeding: Not indicated.
- Dosage: 0.5 mL IM, three doses at 2, 4, and 6 months; booster dose at 12-15 months.
Precautions
*Screen for any history of allergic reaction or neurologic event before administration.
*Postpone in case of moderate or severe illness with/without fever.
FAQs
Q1: What is the recommended dosage for this vaccine?
A: The standard primary series consists of three 0.5 mL doses given intramuscularly at 2, 4, and 6 months of age. A booster dose is recommended at 12–15 months of age.
Q2: Can this vaccine be given with other vaccines?
A: Yes, it can generally be given with other vaccines, but should be administered at different injection sites.
Q3: What are the most common side effects?
A: The most common side effects are mild and include local reactions (pain, redness, swelling), fever, and irritability.
Q4: Who should not receive this vaccine?
A: Individuals with a history of severe allergic reaction to a previous dose or any vaccine component, encephalopathy after a pertussis-containing vaccine, or a progressive neurological disorder should not receive this vaccine.
Q5: What is the difference between DTaP and DTwP?
A: DTaP contains acellular pertussis components, while DTwP contains whole-cell pertussis. DTaP is generally preferred due to a lower risk of side effects.
Q6: How effective is this vaccine?
A: This vaccine is highly effective in preventing the diseases it targets when the full series is completed.
Q7: What should I do if my child has a mild fever after vaccination?
A: A mild fever is a common side effect. You can give your child age-appropriate doses of acetaminophen or ibuprofen to reduce fever and discomfort.
Q8: How long does immunity last after vaccination?
A: Immunity duration varies, and booster doses are necessary to maintain protection.
Q9: What is a hypotonic-hyporesponsive episode (HHE)?
A: An HHE is a rare but serious reaction characterized by a temporary loss of muscle tone and responsiveness. It can occur after vaccination with pertussis-containing vaccines. It typically resolves without long-term consequences.
