Adacel

Diphtheria, Tetanus And Pertussis (acellular, Component) Vaccine (adsorbed)

Treatment option:

Medically reviewed

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Adacel

Quick Facts

Property	Description
Active ingredient	Diphtheria toxoid, Tetanus toxoid, Pertussis antigens
Form	Suspension for injection (Adsorbed)
Pharmacological class	Immunizing agent (Vaccine)
Common use	Prevention of Diphtheria, Tetanus, and Pertussis
Origin	Biological product (Derived from bacterial components)

What Type of Product is Adacel?

Adacel is an immunizing agent and a biological product categorized as a combination vaccine used to establish active immunity against three specific bacterial infections. It is a modern Tdap vaccine that provides protection against diphtheria, tetanus, and pertussis in a single formulation. The product is derived from prepared bacterial components—specifically toxoids and purified antigens—not the whole, live bacteria. The Tdap vaccine is utilized as a tool for sustaining immunity against these pathogens, which helps minimize disease burden across adolescent and adult populations.

Understanding the Composition of Adacel

The formulation includes three sets of active ingredients: Diphtheria toxoid, Tetanus toxoid, and various Pertussis antigens (including filamentous hemagglutinin and pertactin). Adacel is positioned specifically for adolescents and adults (typically aged 10 through 64 years) needing a booster dose, distinguishing it from vaccines used for primary pediatric schedules. It is prepared as a sterile, cloudy white suspension for injection, which is administered through the intramuscular route. Adacel is an adsorbed vaccine, meaning its active components are bound to an adjuvant, Aluminium phosphate. This adjuvant is included to enhance the immune response to the antigens.

The General Purpose of Adacel

The general purpose of Adacel is to establish immunological defense against three serious bacterial illnesses: diphtheria, tetanus (lockjaw), and pertussis (whooping cough). By introducing non-infectious toxoids and purified antigens, the product prepares the body's immune system to launch a rapid, protective response. The efficacy of the Tdap vaccine in preventing whooping cough, a highly contagious respiratory illness, is clinically recognized. This process ensures the body develops active immunity, maintaining a state of readiness that is essential for the long-term prevention of these potentially dangerous diseases.

What side effects are possible with Adacel?

Possible Side Effects and Safety Information

Adacel’s official safety profile is structured around expected local reactions and transient systemic effects, as documented by regulatory bodies such as the U.S. Food and Drug Administration and the European Medicines Agency.

Frequency-Classified Adverse Reactions

The most frequent adverse events fall under the Very Common (ge 1/10) and Common (ge 1/100 to <1/10) classifications. Very Common reactions include localized pain, swelling, and erythema at the injection site, along with systemic effects like headache, tiredness, and myalgia (muscle pain). Common reactions include fever, chills, and nausea.

Adverse events reported primarily through post-marketing surveillance are classified as Frequency Not Known. These include rare but serious events such as anaphylactic reaction, Guillain-Barré syndrome (GBS), brachial neuritis, and myocarditis.

System-Organ Class and Safety Constraints

The documented effects are grouped by System-Organ Classes, encompassing disorders in the Nervous System, Immune System, and Musculoskeletal System. The label includes high-level constraints and contraindications. Adacel is contraindicated in individuals with a known systemic hypersensitivity to any component or a history of encephalopathy within seven days following a prior pertussis-containing vaccine.

For population-specific safety, the label notes that the expected immune response may be reduced in immunocompromised persons. In older adults (ge 65 years), myalgia was reported as a frequent systemic reaction. Local reactions typically occur within three days and resolve within a few days.

Overdose and Emergency Response

Overdose and when to seek help — Official Regulatory Information for Adacel

Element	Official Regulatory Statement
Documented overdose presentations	Overdose is unlikely to occur because the product is administered by a healthcare professional. No distinct syndrome of toxicity linked to dose excess is formally described in major regulatory labels.
Physiological systems affected (as stated in label)	Immune system (manifesting as severe allergic/anaphylactic reaction); Cardiovascular system (potential for low blood pressure or shock); Central Nervous System (potential risk of encephalopathy post-vaccination).
Emergency-response statements	Epinephrine hydrochloride solution (1:1,000) and other appropriate agents must be readily available for immediate use to manage an acute hypersensitivity reaction.
When immediate medical help is required (label-derived phrasing only)	Seek immediate medical attention or call emergency services right away if signs of a severe allergic reaction occur, such as difficulty in breathing, swelling of the face or throat, hives, or collapse.

Overdose Classifications (High-Level)

Element	Official Regulatory Statement
Severity classification	The most severe outcome requiring intervention is classified as a Severe Allergic Reaction or Anaphylaxis.
Overdose-context constraints	The official context is constrained by the fact that the product is a biological product administered in clinical settings, rendering classical overdose unlikely.

Resulting Overdose Structure

Official overdose statements:

Overdose of this vaccine is unlikely to occur, and no specific antidote is known for the management of dose excess according to official labeling.
Immediate medical attention is required upon the onset of signs of a severe reaction, including difficulty in breathing, collapse, or swelling of the face or throat.
Procedural preparedness must include the immediate availability of Epinephrine solution and equipment to manage anaphylaxis.

Connection to the overall overdose profile:

The regulatory documentation defines the Adacel overdose profile by emphasizing that over-administration is unlikely, directing the critical focus toward the required management of severe, life-threatening allergic manifestations. This framework mandates strict procedural preparedness and requires users to seek immediate medical help for the onset of specific, officially documented severe symptoms exactly as outlined in the official prescribing information.

Therapeutic Uses of Adacel

Adacel is relevant for maintaining defense through active booster immunization to prevent three serious bacterial illnesses—tetanus, diphtheria, and pertussis (whooping cough)—and is commonly used to help support sustained protection in adolescents and adults.

Sustaining and Targeted Protection

The primary therapeutic benefit of Adacel involves support for preventing conditions characterized by symptoms of increased neurological or muscular activity (tetanus), airway compromise (diphtheria), and violent, uncontrolled coughing fits (pertussis). Maintaining this protective state may contribute to reducing the overall risk associated with these severe infections, assisting with maintaining functional stability.

Adacel is commonly used in contexts involving long-term immunity maintenance for adolescents and adults, and is relevant in clinical settings for prophylaxis following high-risk injuries like deep cuts. It is also relevant for maternal vaccination during pregnancy to assist with reducing the likelihood of symptoms that interfere with functional stability in newborns. This use is consistent with the product's indications, supporting general well-being through prevention.

“This application is used when appropriate to refresh protection when the risk of contamination is high, supporting the patient during difficult episodes by easing distress.”

Quick Fact Block

Property	Description
Quick Fact: Primary Use	Prevention of Tetanus, Diphtheria, and Pertussis.
Quick Fact: Benefit Focus	Supports sustained immunological defense in older populations.
Quick Fact: Context of Use	Relevant as prophylaxis after tetanus-prone wounds and for infant protection (maternal).

Eligibility and Restrictions for Use

Eligibility Scope

Category	Official Regulatory Statement
Populations for whom use is allowed	Persons 10 through 64 years of age (US-specific booster indication). Individuals from 4 years of age and older (EU/Canada booster indication). Approved for women during the third trimester of pregnancy for infant protection.
Populations for whom use is not recommended	Individuals less than 10 years of age (US label) or under 4 years of age (EU/Canada). Individuals 65 years of age and older (US label) as safety and effectiveness are not established.
Populations for whom use is contraindicated	Persons with a history of severe allergic reaction (anaphylaxis) to any component of Adacel or to a previous dose of any tetanus, diphtheria, or pertussis vaccine. Individuals who developed encephalopathy within 7 days of a previous dose of a pertussis-containing vaccine, not attributable to another cause.

Eligibility-Related Restrictions

Deferral is required for those with progressive or unstable neurological disorders or acute severe febrile illness. Vaccination should be postponed until the condition stabilizes.
Conditional use applies to persons with a history of Guillain-Barré Syndrome (GBS) within 6 weeks of a prior tetanus toxoid vaccine; the decision to proceed requires a careful assessment.
Caution is necessary when administering to individuals with bleeding disorders or those on anticoagulant therapy due to the risk of hematoma following intramuscular injection.
Immunocompromised persons may receive the vaccine according to standard schedules, but the regulatory label notes they may not achieve the expected immune response.

Connection to the Overall Eligibility Profile

Official regulatory documents define Adacel's eligibility profile by specifying approved age ranges for active booster use and establishing absolute prohibitions for individuals with known severe past reactions. Furthermore, the profile outlines specific conditional rules requiring deferral or caution for pre-existing neurological instability or conditions that increase the risk of injection site hematoma, strictly limiting the eligible recipient pool.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The interaction profile of Adacel, an immunizing agent, primarily involves effects on the immune response rather than typical pharmacokinetic or metabolic interactions seen with small-molecule drugs. Interaction data is based on official studies regarding co-administration and the impact of other treatments on the expected immune protection.

Property	Classification
Interaction with Immunosuppressants	Pharmacodynamic interaction: Immunosuppressive treatments, such as corticosteroids and alkylating agents, may result in a reduced or sub-optimal immune response to the vaccine, as documented in regulatory labeling.
Co-administration Effect	Altered Exposure (Antigen): Co-administration with the Trivalent Inactivated Influenza Vaccine (TIV) in adults resulted in a lower antibody response for the pertactin antigen compared to Adacel administered alone.

Administration Rules and Restrictions

The regulatory profile includes strict administration constraints. Adacel must not be mixed with any other vaccine or medicinal product in the same syringe or vial prior to administration, which constitutes a mandatory timing-based interaction rule. Furthermore, the intramuscular injection of Adacel requires specific care in persons receiving anticoagulant therapy or who have coagulation disorders due to the procedural risk of hemorrhage. In these circumstances, the deep subcutaneous route may be considered, although this carries a potential for increased local reactions. The combination is contraindicated if the person experienced encephalopathy within seven days of a previous pertussis-containing vaccine administration where another cause was not identified.

Mechanism of Action

How Adacel Works

Adacel contains adsorbed diphtheria and tetanus toxoids, and acellular pertussis antigens. These components serve as the active biological agents, acting as non-self signals to the host immune system. The adsorbed toxoids and antigens are initially captured and processed by antigen-presenting cells (APCs) in the local tissue and adjacent lymph nodes.

These APCs then present the antigenic fragments to both B-lymphocytes and T-lymphocytes via the major histocompatibility complex (MHC). This cellular interaction initiates the adaptive immune response, stimulating the clonal expansion of B-cells and the production of specific antibodies. Concurrently, a T-cell activation cascade is generated, which leads to the differentiation of helper T-cells and the formation of memory T-cells.

The resulting circulating antibodies and the population of immunological memory cells provide the foundation for a rapid and specific recall response upon subsequent encounter with the native bacterial components. The presence of these systemic antibodies provides the basis for long-term immunological memory against the specific bacterial components.

Dosage and Administration Information

Adacel, a Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis (Tdap) Vaccine, is administered as a 0.5 mL injection exclusively via the intramuscular (IM) route. This vaccine is approved for use in individuals from 10 through 64 years of age for active booster immunization against tetanus, diphtheria, and pertussis.

Administration and Dosage

The appropriate dosage and schedule depend on the patient's age, vaccination history, and the purpose of the immunization:

Routine Booster Vaccination: The first dose of Adacel should be administered 5 years or more after the last dose of the Diphtheria and Tetanus Toxoids and Acellular Pertussis (DTaP) series or Tetanus and Diphtheria Toxoids Adsorbed (Td) vaccine. A second dose of Adacel may be administered 8 years or more after the first Tdap dose.
Wound Management: For tetanus prophylaxis in a tetanus-prone wound, a booster dose of Adacel may be administered if at least 5 years have elapsed since the previous receipt of any tetanus toxoid-containing vaccine.
Immunization During Pregnancy: Adacel is indicated for administration during the third trimester of pregnancy to provide protection against pertussis in infants younger than 2 months of age.

Preparation and Safety

Before use, the vial or prefilled syringe must be shaken well until a uniform, cloudy, whitish-gray suspension is achieved. The product should be visually inspected for particulate matter or discoloration prior to administration, and if either is present, the vaccine must not be administered. Adacel must not be mixed with any other vaccine and should not be administered by intravascular, intradermal, or subcutaneous routes.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Adacel

Evidence for Active Booster Immunization

The core research base for Adacel as a booster vaccine primarily involves short-term clinical trials that studies explored how the product was associated with changes in the immune system. These studies were mainly focused on measuring immunogenicity, meaning they assessed the creation and levels of antibodies in the blood, rather than tracking long-term disease prevention. Research primarily examined adolescents (aged 10 and up) and adults up to age 64.

Findings indicated that the vaccine was associated with the measured presence of antibody concentrations at established regulatory thresholds against Tetanus and Diphtheria. Comparisons with the older Tetanus and Diphtheria-only vaccine component research described that the Tdap formulation demonstrated antibody measurements consistent with those observed for the Tetanus and Diphtheria components of the older vaccine. Evidence for sustained immune response against Pertussis disease beyond a few years relies heavily on following the pattern of antibody decline, and data for certain groups, such as adults aged 65 and older, remain insufficient from the core licensing trials.

Evidence for Protecting Infants via Maternal Vaccination

Another major area of research explored the use of the Tdap vaccine in pregnant women to support newborns' defense against Whooping Cough. The main outcomes studied included the rate of Pertussis disease in infants during their first few months of life, and research also evaluated the measurement of antibodies transferred from the mother to the baby. Studies report patterns of lower reported disease occurrence in infants whose mothers received the Tdap vaccine during pregnancy compared to infants of unvaccinated mothers.

Evidence for Tetanus Prophylaxis in Wound Management

The vaccine was evaluated in research contexts involving injuries where Tetanus infection is a risk, often referred to as "tetanus-prone wounds." Studies explored whether the Tdap vaccine could be used in a manner similar to the older Td vaccine for immediate use. Studies reported that the Tetanus component of Adacel was associated with measured antibody levels consistent with those observed for the Tetanus component of the traditional Td vaccine in these scenarios.

Long-Term Studies and Durability of Protection

Research has explored the longevity of the initial immune response, particularly for the Pertussis components, which evidence suggests may lessen over time. Studies examined the immune response to repeat Tdap dosing administered approximately eight years or more after the first. Findings indicate that a second dose was studied for its association with the observed return of antibody levels towards those measured immediately after the first dose. Data are still emerging for long-term effectiveness, and existing studies provide limited insight into the duration of immune response maintenance against Pertussis over an entire adult lifespan.

Research Gaps and Uncertainties

While Adacel contributes to the broader evidence landscape, data for certain groups, specifically individuals aged 65 and older, remain insufficient in the main product studies, meaning results apply only to the populations studied. Research is also ongoing to fully understand any potential long-term effects on the child’s immune development following their own primary vaccination schedule after maternal vaccination.

Frequently Asked Questions (FAQ)

Common questions about Adacel (FAQ)

Q: How is Adacel different from the DTaP vaccine?

Adacel (Tdap) is formally classified as a booster vaccine that is licensed for use in adolescents and adults. The key distinction from the childhood DTaP vaccine lies in its composition; Tdap contains a reduced concentration of the diphtheria and pertussis components. This formulation is intended to boost previously acquired immunity rather than establishing primary protection.

Q: Is Adacel the same as Boostrix?

Adacel and Boostrix are both FDA-approved Tdap booster vaccines used for the prevention of tetanus, diphtheria, and pertussis. According to official statements, they differ in their approved age ranges and the specific pertussis antigens included in their formulations. Both are separate brand names for similar vaccines. A healthcare provider can offer more details regarding the approved use of similar products.

Q: How long does the protection from Adacel last?

Official guidance indicates that the schedule for protection against tetanus and diphtheria involves routine booster doses, which are typically administered every 10 years. Research has shown that immunity against the pertussis component following Tdap may wane (decrease) after a few years, but repeat vaccination is not routinely recommended for pertussis alone.

Q: Is it possible for Adacel to stop working over time?

Official studies indicate that immunity following Tdap vaccination, particularly the protection against pertussis, may lessen over time (known as waning immunity). However, protection against tetanus and diphtheria is sustained longer and is associated with adherence to the recommended 10-year booster schedule.

Q: Is it normal to feel extra tired the day after receiving Adacel?

Yes, regulatory documents list tiredness (fatigue) as a common or most frequent systemic reaction reported in clinical trials. These effects are considered transient, meaning they are typically expected to resolve within the first three days following vaccination.

Q: What happens if someone misses their scheduled dose of Adacel?

According to official public health guidance, if an adolescent or adult has missed a scheduled dose, Adacel can be administered at the next patient encounter without regard to the exact time interval that has passed since their last tetanus or diphtheria-containing vaccine was received.

Q: Is there a link between Adacel and Guillain-Barré syndrome mentioned in official sources?

Guillain-Barré syndrome (GBS) is listed in the official label as an adverse event reported primarily through post-marketing surveillance. The official label notes that a history of GBS within six weeks of a previous tetanus toxoid-containing vaccine is a factor that is considered during the risk-benefit assessment.

Q: Does Adacel contain thimerosal or mercury?

The official formulation of Adacel, as described in the prescribing information, does not contain thimerosal or any other preservative. The active ingredients of the vaccine are adsorbed to Aluminum phosphate, which is an adjuvant that helps the body develop an immune response.

Q: Is Adacel a brand name, and what is the generic name?

Adacel is the brand name for this specific product. The official generic classification for this type of vaccine is the Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis Vaccine, Adsorbed, commonly abbreviated as Tdap.

Q: What is the difference in side effects between Adacel and older Td vaccines?

Data from clinical trials comparing the safety profile of Adacel (Tdap) to the older Td vaccine have been reviewed. These studies found no significant differences in the rates of expected injection-site reactions, systemic reactions, or serious adverse events between the two groups.

Q: If I have a history of seizures, can I still receive Adacel?

A history of controlled epilepsy or seizures is generally not considered a contraindication. However, the official guidance advises that vaccination should be deferred for individuals with uncontrolled seizures or any progressive neurological disorder until their condition has been evaluated and stabilized.

Q: What is the official recommendation regarding people who are breastfeeding and Adacel?

Official prescribing information notes that it is not known whether the vaccine’s active components are excreted in human milk. Since Adacel is an inactivated vaccine (meaning it contains no live bacteria or virus), any potential risk to a breastfeeding infant is considered unlikely. The use of the vaccine during breastfeeding involves a consideration of the potential benefits and risks, as is standard for many medical products.

Q: Can Adacel cause swollen lymph nodes?

Official documentation from post-marketing surveillance has included reports of swollen lymph nodes (lymphadenopathy) as an adverse event. While not classified as a very common event in initial trials, this reaction has been reported to regulatory authorities.

Q: Are there differences in how Adacel is used in different countries?

Yes, differences exist in the approved age range for the active booster dose depending on the regulatory body. For example, the US label is specified for persons aged 10 through 64 years, while regulatory bodies in other regions (such as the EU/Canada) may approve use starting from individuals 4 years of age and older.

Q: Is it possible to receive Adacel too often?

Official guidance specifies the minimum time intervals between doses (e.g., 5 years between DTaP and Tdap, and 8 years between Tdap doses). Safety studies have not found an elevated risk of injection-site or systemic reactions when repeated Tdap vaccination is administered at intervals shorter than the typical 10-year Td booster recommendation.

How should Adacel be stored and disposed of?

Adacel must be stored and handled according to strict regulatory guidelines to maintain its effectiveness as a biological product.

Official Storage Conditions

Requirement	Description (Based on Regulatory Labeling)
Temperature	Store in a refrigerator between 2 C and 8 C (35 F and 46 F).
Protection	Keep the vaccine in its original package to protect it from light.
Prohibition	Do not freeze. Freezing destroys the vaccine and necessitates immediate disposal.

Handling and Disposal

Before use, the vaccine must be shaken well to ensure the suspension is uniform and visually inspected for particles or discoloration. The vaccine must be discarded immediately if it has been frozen or if the expiry date has passed. Disposal of any unused or expired product, including needles and syringes, must be done in compliance with local requirements for pharmaceutical and biohazard waste. The product must be stored out of the sight and reach of children.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.