A sterile suspension of purified, inactivated toxoids of Corynebacterium diphtheriae and Clostridium tetani, combined with purified, inactivated Bordetella pertussis antigens, adsorbed onto an aluminum adjuvant (aluminum hydroxide or aluminum phosphate). It is a combined vaccine for active immunization against diphtheria, tetanus, and pertussis (whooping cough). The formulation (2IU/20IU/8mcg) is typically used as a booster dose in children, adolescents, and adults, following primary immunization with a higher-strength pertussis antigen pediatric formulation.
Adult: A single 0.5 mL intramuscular booster dose. For adults >19 years, one dose of Tdap is recommended, followed by Td (tetanus-diphtheria) boosters every 10 years.
Note: Shake the vial or pre-filled syringe well before use to form a homogeneous, white, cloudy suspension. Administer by deep intramuscular injection, preferably into the deltoid muscle (upper arm) in older children and adults, or the anterolateral thigh in younger children. Do not inject intravenously, intradermally, or subcutaneously. Use a separate, sterile syringe and needle for each individual.
The vaccine contains detoxified bacterial toxins (toxoids) and purified bacterial components. Upon intramuscular administration, the aluminum-adsorbed antigens are taken up by antigen-presenting cells (APCs) at the injection site and transported to draining lymph nodes. APCs present processed antigen peptides to CD4+ T-helper cells, which stimulate B-lymphocytes to proliferate and differentiate into memory B-cells and antibody-producing plasma cells. This induces a humoral immune response, generating neutralizing antibodies (mainly IgG) against diphtheria toxin, tetanus toxin, and pertussis antigens (like pertactin, filamentous hemagglutinin). These antibodies provide protection by neutralizing the respective toxins or facilitating opsonization of bacteria upon future exposure.
Pregnancy: Category B (US FDA). Not routinely recommended for primary use during pregnancy in India unless part of a specific outbreak response. However, international guidelines (ACOG, CDC) recommend a dose during each pregnancy (27-36 weeks) to protect the newborn. The Indian context currently follows a more conservative approach; use should be based on a careful risk-benefit assessment by the treating obstetrician.
Driving: Vaccine may cause dizziness, fatigue, or syncope (fainting). Patients should be advised not to drive or operate heavy machinery for a few hours post-vaccination if they feel unwell.
| Immunosuppressants (e.g., high-dose corticosteroids, chemotherapy, biologics like TNF-alpha inhibitors) | Diminished immunogenic response; may not elicit protective antibody levels. | Major |
| Anticoagulants (e.g., Warfarin) | Increased risk of hematoma at injection site; use fine needle and apply firm pressure. | Moderate |
| Other Vaccines (Live or Inactivated) | Can generally be administered simultaneously at different anatomical sites. No clinically significant interference in immune response when given with common vaccines like Influenza, Hepatitis B. | Minor |
Same composition (Diphtheria Toxoid (2IU) + Tetanus Toxoid (20IU) + Pertussis Toxoid (8mcg)), different brands: