Diphtheria Toxoid + Pertussis Toxoid + Tetanus Toxoid

Usage

This combination vaccine is prescribed for active immunization against diphtheria, tetanus, and pertussis. Specifically, it stimulates an immune response to produce antibodies against these diseases.

• Pharmacological Classification: Vaccine/Immunizing Agent/Toxoid
• Mechanism of Action: This trivalent vaccine works by introducing inactivated toxins (toxoids) from the causative bacteria for diphtheria and tetanus, and components of Bordetella pertussis (acellular pertussis), into the body. These components are unable to cause the disease but are sufficient to trigger an immune response, leading to the production of antibodies that provide immunity against future infections.

Alternate Names

• DTaP (for use in children under 7 years)
• Tdap (for use in adolescents and adults; contains lower doses of diphtheria and pertussis toxoids)
• DTPa
• DTP
• Td
• DTwP (whole-cell pertussis vaccine, not available in the US)

Brand names: Infanrix, Daptacel, Kinrix, Pediarix, Pentacel, Quadracel, Vaxelis, Adacel, Boostrix, TENIVAC, TDVAX.

How It Works

• Pharmacodynamics: The vaccine prompts the immune system to generate specific antibodies against diphtheria, tetanus, and pertussis toxins and antigens. These antibodies neutralize the toxins and bacteria upon subsequent natural exposure, preventing disease onset.
• Pharmacokinetics: The toxoids and acellular pertussis components are administered intramuscularly. Absorption from the injection site leads to systemic distribution and processing by the immune system. Elimination of the vaccine components and their metabolites likely occurs through various pathways, including renal and hepatic mechanisms. The duration of protection varies but booster doses are necessary to maintain immunity.

Dosage

Standard Dosage

Adults (Tdap):

• 0.5 mL intramuscularly as a single dose.
• A Td booster is recommended every 10 years.

Children (DTaP):

• 0.5 mL intramuscularly. A primary series of 5 doses is given at 2, 4, 6, and 15-18 months, and 4-6 years of age.
• The fifth dose may not be necessary if the fourth dose was given at or after age 4 and at least 6 months after the third dose.
• A single Tdap booster is administered at age 11-12.

Special Cases:

• Elderly Patients: The standard adult Tdap dose is typically used.
• Patients with Renal Impairment: No specific dosage adjustment is generally recommended.
• Patients with Hepatic Dysfunction: No specific dosage adjustment is generally recommended.
• Pregnant Women: Tdap is recommended during each pregnancy, preferably at 27-36 weeks gestation, regardless of prior Tdap history.

Clinical Use Cases The listed clinical use cases do not necessitate dosage change.

• Intubation
• Surgical Procedures
• Mechanical Ventilation
• Intensive Care Unit (ICU) Use
• Emergency Situations

Side Effects

Common Side Effects:

• Injection site reactions (pain, redness, swelling)
• Fever
• Headache
• Fatigue
• Nausea, vomiting, diarrhea
• Irritability (in children)

Rare but Serious Side Effects:

• Encephalopathy (within 7 days)
• Seizures (within 3 days)
• Persistent, inconsolable crying (≥ 3 hours within 48 hours)
• Collapse or shock (within 48 hours)
• High fever (≥ 40.5°C/105°F within 48 hours)
• Severe allergic reaction (anaphylaxis)

Long-Term Effects: No specific long-term adverse effects are known to be associated with the DTaP/Tdap vaccines.

Adverse Drug Reactions (ADR): Any signs of encephalopathy, seizures, or severe allergic reactions require immediate medical attention.

Contraindications

• Severe allergic reaction (e.g., anaphylaxis) to a previous dose or to a vaccine component
• Encephalopathy within 7 days of a prior dose of pertussis-containing vaccine
• Progressive or unstable neurological disorder, uncontrolled seizures, or progressive encephalopathy (for pertussis-containing vaccines, defer until stabilized)

Drug Interactions

• Immunosuppressants (e.g., corticosteroids, chemotherapy): May decrease the immune response to the vaccine.
• Other vaccines: Can generally be co-administered but should be given with separate syringes and at different injection sites. Concomitant administration of DTaP and inactivated influenza vaccine may slightly increase the risk of febrile seizures in young children.

Pregnancy and Breastfeeding

• Pregnancy: Tdap is recommended during each pregnancy (preferably at 27-36 weeks gestation) regardless of the patient’s Tdap history. Data does not indicate any risk to the fetus. Maternal vaccination provides passive immunity to the newborn against pertussis.

• Breastfeeding: Tdap is safe for breastfeeding mothers. It poses no known risks to the infant.

Drug Profile Summary

• Mechanism of Action: Stimulates antibody production against diphtheria, tetanus, and pertussis.
• Side Effects: Common: injection site reactions, fever, fatigue. Rare but serious: encephalopathy, seizures, allergic reactions.
• Contraindications: Prior severe allergic reaction, encephalopathy after a previous dose, certain neurological disorders.
• Drug Interactions: Immunosuppressants.
• Pregnancy & Breastfeeding: Safe during both. Recommended for pregnant women.
• Dosage: Adults: 0.5 mL Tdap once, then Td every 10 years. Children: 0.5 mL DTaP at 2, 4, 6, 15-18 months, and 4-6 years; Tdap booster at 11-12 years.
• Monitoring Parameters: Monitor for any signs of adverse reactions, particularly in the days following vaccination.

Popular Combinations

DTaP is often combined with other vaccines, such as inactivated poliovirus (IPV) and Haemophilus influenzae type b (Hib) vaccines, for ease of administration during childhood vaccinations.

Precautions

• Postpone vaccination in patients with moderate or severe acute illness.
• Pre-screening for allergies to vaccine components is essential.
• Caution in individuals with a history of Guillain-Barré syndrome following a prior tetanus-containing vaccine.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Diphtheria Toxoid + Pertussis Toxoid + Tetanus Toxoid?

A: DTaP: 0.5 mL intramuscularly at 2, 4, 6, 15-18 months, and 4-6 years of age. Tdap: 0.5 mL intramuscularly once for adolescents and adults (preferably between 27 and 36 weeks gestation for pregnant women). A Td booster is recommended every 10 years.

Q2: What are the common side effects?

A: Pain, redness, or swelling at the injection site, mild fever, fatigue, headache, nausea, and irritability (in children).

Q3: When should Tdap be administered during pregnancy?

A: Preferably between 27 and 36 weeks gestation.

Q4: Can DTaP/Tdap be given with other vaccines?

A: Yes, but preferably with separate syringes and at different injection sites.

Q5: What is the difference between DTaP and Tdap?

A: DTaP is for children under 7, while Tdap (containing lower doses of diphtheria and pertussis toxoids) is for adolescents and adults.

Q6: Who should not receive this vaccine?

A: Individuals with a history of severe allergic reaction to a prior dose or a vaccine component, encephalopathy following a prior dose of pertussis-containing vaccine, or certain unstable neurological disorders.

Q7: What should I do if a patient experiences a serious reaction?

A: Seek immediate medical attention. Report adverse events to relevant health authorities.

Q8: Does the vaccine offer complete protection against these diseases?

A: While highly effective, the vaccines do not guarantee 100% protection. Some individuals may still contract these diseases, though typically with milder symptoms.

Q9: What is the role of booster doses?

A: Booster doses are essential for maintaining long-term immunity, as the protection provided by the initial doses wanes over time.

Q10: How long does the protection from this vaccine last?

A: Protection varies, but booster doses of Td are recommended every 10 years for adults to maintain adequate levels of immunity against tetanus and diphtheria.