ADACEL POLIO {DIPHTHERIA TETANUS PERTUSSIS ACELLULAR COMPONENT) AND POLIOMYELITIS (INACTIVATED VACCINE (ADSORBED REDUCED ANTIGENS)}

Indications

• Prevention of whooping cough (pertussis)
• Part of combination vaccines such as DTaP (diphtheria, tetanus, and acellular pertussis)
• Vaccination in infants and children as per national immunization schedules

Dosage

Children: Refer to the BNF for Children for specific dosages based on age and vaccine type.

Adults: Refer to specific vaccine guidelines; dosages may vary based on the vaccine formulation and local health authority recommendations.

Mechanism of action

Acellular vaccines function by introducing specific antigens derived from the pathogen into the body. This prompts the immune system to recognize these components as foreign, leading to the activation of B cells and T cells. The B cells produce antibodies against the antigens, while T cells help to clear any infected cells. This immune memory allows for a quicker and more effective response if the individual is exposed to the actual pathogen in the future.

Pharmacodynamics

The pharmacodynamics of acellular vaccines involve the stimulation of both humoral (antibody-mediated) and cellular (T cell-mediated) immune responses. The presence of adjuvants in some formulations may enhance the immune response by promoting a stronger and longer-lasting immunity to the antigens presented. The effectiveness of the immune response can vary based on factors such as age, health status, and prior exposure to the pathogens.

Pharmacokinetics

Acellular vaccines are typically administered via intramuscular injection. After administration, the antigens are taken up by antigen-presenting cells, which then migrate to lymph nodes to stimulate T and B cell activation. The onset of immunity usually occurs within weeks, with peak antibody levels achieved several weeks after vaccination. The duration of immunity can vary depending on the vaccine and the specific antigens used, and booster doses may be required to maintain immunity over time.

Pregnancy

Safety during pregnancy has not been established; consult a healthcare provider.

Breast-feeding

Consult a healthcare provider regarding use during breastfeeding.

Storage

Store in a cool, dry place away from direct sunlight, at temperatures below 25°C.

Indications

• Vaccination against infectious diseases
• Diagnosis of allergies
• Cancer immunotherapy
• Autoimmune disease modulation

Dosage

Children: Refer to specific product guidelines as doses can vary based on the antigen and the purpose of administration.

Adults: Refer to specific product guidelines as doses can vary based on the antigen and the purpose of administration.

Mechanism of action

Antigens act by binding to specific receptors on immune cells, such as B cells and T cells. This binding activates these cells, leading to the production of antibodies (in the case of B cells) or cytotoxic responses (in the case of T cells). The recognition of antigens by the immune system involves antigen presentation by Major Histocompatibility Complex (MHC) molecules, which display peptide fragments of the antigen on the surface of antigen-presenting cells.

Pharmacodynamics

The presence of antigens triggers a series of immune responses, including the activation of lymphocytes, cytokine production, and the formation of memory cells. These processes are essential for the body to recognize and mount an effective defense against subsequent exposures to the same antigen, contributing to immunological memory and long-term protection.

Pharmacokinetics

The pharmacokinetics of antigens can vary widely depending on their nature and route of administration. Generally, antigens can be administered via intramuscular, subcutaneous, or intradermal routes. Upon administration, they are processed by antigen-presenting cells, which then migrate to lymph nodes to activate T and B cells. The distribution, metabolism, and elimination of antigens depend on their structure and the immune response they elicit.

Adverse effects

• Local reactions at the injection site
• Systemic allergic reactions
• Fever
• Fatigue
• Headache
• Nausea

Precautions

• Monitor for allergic reactions after administration
• Use with caution in individuals with a history of severe allergic reactions
• Consider the patient's immune status before administration

Pregnancy

Consult a healthcare professional before use. The safety of antigens in pregnancy varies depending on the type of antigen and the specific clinical context.

Breast-feeding

Consult a healthcare professional before use. The transfer of antigens into breast milk is variable and depends on the type of antigen.

Storage

Store at recommended temperatures, usually between 2°C and 8°C. Protect from light and do not freeze.

Formulations

• Injectable solutions
• Suspensions
• Lyophilized powders for reconstitution

Indications

• Prevention of diphtheria through vaccination
• Treatment of diphtheria infection
• Management of respiratory obstruction due to pseudomembrane

Dosage

Children: Refer to specific

Adults: Refer to specific guidelines for the treatment of diphtheria. Antitoxin and antibiotics are typically used in treatment.

Mechanism of action

The pathogenicity of Corynebacterium diphtheriae is largely due to its production of diphtheria toxin, an A-B toxin that inhibits protein synthesis in host cells. The toxin is composed of two subunits: the A subunit, which enters the cytoplasm of the cell and catalyzes the ADP-ribosylation of elongation factor 2 (EF-2), leading to cell death, and the B subunit, which binds to the cell surface receptor, facilitating the entry of the A subunit. This results in local tissue damage and systemic effects, including myocarditis and neuropathy.

Pharmacodynamics

Diphtheria toxin exerts its effects primarily through inhibiting protein synthesis, causing cell death in susceptible tissues. The resulting necrosis can lead to the characteristic pseudomembrane formation in the throat and can affect other organs, including the heart and nervous system. The immune response to the toxin and the bacteria provides some level of protection, which is the basis for vaccination strategies.

Pharmacokinetics

The pharmacokinetics of the diphtheria toxin itself are not typically described in terms of absorption, distribution, metabolism, and excretion, as it is a potent toxin rather than a conventional drug. However, the body’s immune response to the toxin is crucial for recovery. After vaccination, the body generates antibodies against the toxin, which can neutralize its effects upon exposure to the bacterium.

Pregnancy

Diphtheria vaccination is recommended during pregnancy to protect the mother and fetus. The vaccine is inactivated and poses no risk.

Breast-feeding

Diphtheria vaccination is safe during breastfeeding. Antibodies may be transferred to the infant through breast milk.

Storage

Store in a refrigerator at 2-8 degrees Celsius. Do not freeze.

Formulations

• Diphtheria toxoid vaccine

Dosage

Children: Refer to specific clinical guidelines and BNF for Children for dosing information.

Adults: Refer to specific clinical guidelines and BNF for dosing information.

Mechanism of action

The mechanism of action for filamentous agents can vary widely but generally involves the inhibition of cell wall synthesis, disruption of cell membrane integrity, or interference with nucleic acid synthesis. For example, in the case of certain filamentous fungi, agents may target ergosterol synthesis, a key component of fungal cell membranes, leading to cell lysis and death.

Pharmacodynamics

Pharmacodynamics of filamentous agents typically includes the assessment of their effects on target microorganisms, including bactericidal or bacteriostatic activity. These agents may exhibit time-dependent or concentration-dependent killing, influencing the choice of dosing regimens. Their efficacy can be influenced by factors such as the growth phase of the microorganism, the presence of biofilms, and the ability of the agent to penetrate tissues.

Pharmacokinetics

The pharmacokinetics of filamentous agents vary based on their chemical structure and route of administration. Common parameters include absorption, distribution, metabolism, and excretion. Many filamentous agents are administered intravenously due to poor oral bioavailability. They may also have a large volume of distribution, indicating extensive tissue binding. Metabolism can occur in the liver, and renal excretion is common, necessitating dose adjustments in patients with renal impairment.

Pregnancy

Safety during pregnancy has not been established. Consult a healthcare provider.

Breast-feeding

Consult a healthcare provider before use while breastfeeding.

Storage

Store in a cool, dry place away from direct sunlight.

Indications

• Bacterial infections
• Urinary tract infections
• Gastrointestinal infections
• Respiratory infections

Dosage

Children: Refer to relevant clinical guidelines for specific dosing information based on the type of bacterial infection.

Adults: Refer to relevant clinical guidelines for specific dosing information based on the type of bacterial infection.

Mechanism of action

Fimbriae mediate adhesion by interacting with specific receptors on host cells. This interaction facilitates the adherence of bacteria to epithelial surfaces, which is a critical step in the establishment of infection. Some fimbriae can also contribute to the formation of biofilms, enhancing bacterial survival in hostile environments.

Pharmacodynamics

The pharmacodynamics of fimbriae relate primarily to their ability to enhance bacterial adherence and colonization. By facilitating the attachment of bacteria to host tissues, fimbriae increase the likelihood of infection and can influence the severity and persistence of bacterial diseases.

Pharmacokinetics

As fimbriae are structural components of bacterial cells, they do not have a pharmacokinetic profile like conventional drugs. Instead, their presence and expression can vary among different bacterial species and strains, affecting their pathogenicity and the clinical outcomes of infections.

Pregnancy

Data on the use of fimbriae during pregnancy is limited. Consultation with a healthcare provider is recommended.

Breast-feeding

Limited data is available regarding the effects of fimbriae during breastfeeding. Consultation with a healthcare provider is recommended.

Storage

Store in a cool, dry place away from direct sunlight and moisture.

Indications

• Influenza prevention
• Influenza treatment
• Vaccine development for influenza

Dosage

Children: Refer to specific treatment guidelines for paediatric influenza management based on age and clinical presentation, as haemagglutinin is not administered as a standalone drug.

Adults: Refer to specific treatment guidelines for influenza based on clinical presentation and guidelines, as haemagglutinin is not administered as a standalone drug.

Mechanism of action

Haemagglutinin functions by specifically binding to sialic acid-containing receptors on the surface of host cells. This interaction triggers endocytosis of the virus, allowing it to enter the host cell. Once inside, the virus can release its genetic material, hijacking the host's cellular machinery to replicate and produce new viral particles. The specificity of haemagglutinin for different sialic acid variants influences the infectivity and host range of the virus.

Pharmacodynamics

The pharmacodynamics of haemagglutinin are closely tied to its role in viral pathogenesis. The strength and specificity of the binding between haemagglutinin and sialic acid receptors determine the virus's ability to infect specific tissues and initiate disease. Antibodies against haemagglutinin can neutralize the virus and are a key component of the immune response, which can lead to protective immunity following infection or vaccination.

Pharmacokinetics

As a component of a virus, haemagglutinin does not have pharmacokinetic parameters like absorption, distribution, metabolism, and excretion as traditional drugs do. Instead, its activity is related to the lifecycle of the virus it is part of. The degradation and clearance of haemagglutinin are dependent on the metabolism of the viral particles by the host's immune system and cellular mechanisms.

Pregnancy

Insufficient data available on the use of haemagglutinin during pregnancy. Consult healthcare providers for advice.

Breast-feeding

Data on the excretion of haemagglutinin in breast milk is not available. Caution is advised.

Storage

Store at 2-8°C. Protect from light and moisture.

Indications

• Hepatitis A
• Hepatitis B
• Influenza
• Polio
• Rabies
• Typhoid fever

Dosage

Children: Refer to specific product guidelines for paediatric dosing, as it varies by vaccine type and indication.

Adults: Refer to specific product guidelines for adult dosing, as it varies by vaccine type and indication.

Mechanism of action

Inactivated vaccines work by introducing a form of the pathogen that cannot cause disease into the body. This stimulates the immune system to produce antibodies and memory cells specific to the pathogen, allowing for a robust immune response upon future exposure. The immune system recognizes the inactivated pathogen as foreign, leading to the activation of T-cells and B-cells, which are crucial for long-term immunity.

Pharmacodynamics

The pharmacodynamics of inactivated vaccines involve the generation of an adaptive immune response. After vaccination, the body produces specific antibodies against the inactivated pathogen. The response typically includes both humoral immunity, characterized by antibody production, and cellular immunity, involving T-cell activation. The duration of immunity can vary, and booster doses may be required to maintain adequate protection.

Pharmacokinetics

Inactivated vaccines do not have a pharmacokinetic profile like traditional drugs since they do not enter systemic circulation in the same manner. Following administration, the vaccine components are taken up by antigen-presenting cells, which process and present the antigens to T-cells. The immune response is initiated locally at the site of injection and can be influenced by factors such as the route of administration and the presence of adjuvants that enhance the immune response.

Adverse effects

• Injection site reactions (pain, swelling, redness)
• Fever
• Fatigue
• Headache
• Myalgia
• Chills

Precautions

• Assess for allergies to vaccine components
• Monitor for allergic reactions post-administration
• Consider underlying health conditions that may affect immune response

Pregnancy

Inactivated vaccines are generally considered safe during pregnancy, but individual risk-benefit assessment is recommended.

Breast-feeding

Inactivated vaccines can be administered during breastfeeding without concern for adverse effects in the infant.

Storage

Store in a refrigerator at 2°C to 8°C. Do not freeze.

Formulations

• Inactivated viral vaccines
• Inactivated bacterial vaccines

Indications

• Prevention of whooping cough (pertussis)
• Vaccination in children and adults to promote immunity against Bordetella pertussis

Dosage

Children: Refer to specific vaccine guidelines for administration.

Adults: Refer to specific vaccine guidelines for administration.

Mechanism of action

Pertactin mediates adherence of Bordetella pertussis to host epithelial cells through interaction with host cell receptors. This binding is crucial for colonization and subsequent infection. It also elicits an immune response that promotes antibody production, which aids in protection against future infections.

Pharmacodynamics

Pertactin is classified as an adhesin, which means it enables bacterial adherence to host tissues. This property enhances the virulence of Bordetella pertussis, leading to increased infection rates and severity of disease. The immune response generated by pertactin contributes to the development of immunity following vaccination, although it is not solely responsible for the protective effect.

Pharmacokinetics

Pertactin is a protein that is generally administered as part of a vaccine. Its pharmacokinetics in terms of absorption, distribution, metabolism, and excretion are not typically characterized in the same way as traditional drugs, since its primary role is to induce an immune response rather than exert direct pharmacological effects. Following vaccination, pertactin is recognized by the immune system, leading to the production of specific antibodies. These antibodies persist and provide long-term immunity.

Pregnancy

There is limited information regarding the safety of pertactin during pregnancy. Caution should be exercised when administering this drug to pregnant individuals.

Breast-feeding

It is unknown whether pertactin is excreted in human breast milk. Caution is advised when administering to nursing mothers.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Indications

• Whooping cough (pertussis)
• Prevention of pertussis in infants and young children through vaccination

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Pertussis toxin, produced by Bordetella pertussis, acts on host cells by ADP-ribosylating a G protein, which disrupts normal signal transduction pathways. This leads to increased production of cyclic AMP, inhibiting immune responses and contributing to the characteristic symptoms of the disease.

Pharmacodynamics

The clinical manifestations of pertussis are largely due to the immune response to the toxin and the bacterium itself. The disease progresses through stages: the catarrhal stage with mild symptoms, the paroxysmal stage with intense coughing fits, and the convalescent stage where symptoms gradually improve. The severity can vary, particularly in infants and young children, who are at higher risk for complications.

Pharmacokinetics

The pharmacokinetics of Bordetella pertussis are not typically described in the same manner as pharmaceutical agents. The organism does not have a traditional pharmacokinetic profile, but it primarily colonizes the ciliated epithelial cells of the upper respiratory tract. The immune clearance of the bacteria can take several weeks, depending on the host's immune response and treatment.

Adverse effects

• Cough
• Vomiting
• Fatigue
• Apnea (especially in infants)
• Weight loss
• Paroxysms of coughing
• Encephalopathy (rare)
• Pneumonia (secondary infection)

Precautions

• Use with caution in individuals with a history of seizures
• Consider potential for severe respiratory distress, especially in infants
• Monitor for complications, particularly in young children

Pregnancy

Pertussis vaccination is recommended during pregnancy to protect the newborn, especially during outbreaks.

Breast-feeding

Vaccination during breastfeeding is safe and can provide passive immunity to the infant.

Storage

Store in a cool, dry place away from direct sunlight. Follow specific storage instructions for vaccines.

Formulations

• DTaP vaccine (Diphtheria, Tetanus, and Pertussis)
• Tdap vaccine (Tetanus, Diphtheria, and Pertussis)

Indications

• Prevention of poliomyelitis infection
• Vaccination in children and high-risk populations

Dosage

Children: Refer to the BNF for Children for specific dosages and recommendations for vaccination schedules.

Adults: Refer to specific vaccination guidelines for adults, as dosages may vary based on risk factors and prior vaccination history.

Mechanism of action

Poliovirus enters the body through the oral route, replicating in the oropharynx and gastrointestinal tract before spreading to the central nervous system via the bloodstream. Once inside the CNS, the virus selectively infects motor neurons in the anterior horn of the spinal cord, leading to cell lysis and resulting in muscle weakness or paralysis. The immune response to the virus contributes to inflammation and further neuronal damage.

Pharmacodynamics

The poliovirus's pathogenicity is primarily due to its ability to evade the host's immune response and its selective neurotropism. The destruction of motor neurons leads to flaccid paralysis, with recovery possible in some cases as the motor neurons may regenerate. The severity of the disease correlates with the extent of neuronal involvement, which can vary widely among individuals.

Pharmacokinetics

Poliovirus is an RNA virus that does not undergo traditional pharmacokinetic processes as it is not treated with drugs. Instead, the prevention of polio relies on vaccination strategies. The inactivated poliovirus vaccine (IPV) and the oral poliovirus vaccine (OPV) are used to induce immunity. After administration, the vaccines promote the development of antibodies against the virus without causing disease.

Contra-indications

• Hypersensitivity to the vaccine component
• Severe immunodeficiency
• Acute febrile illness

Adverse effects

• Pain at injection site
• Fever
• Fatigue
• Headache
• Nausea
• Allergic reactions

Interactions

• Immunosuppressive therapies may reduce vaccine efficacy
• Concomitant administration with other vaccines may affect immune response

Precautions

• Use with caution in individuals with moderate to severe acute illness
• Consider history of allergic reactions
• Monitor for signs of anaphylaxis after administration

Pregnancy

Poliomyelitis vaccination is generally considered safe during pregnancy, but consult a healthcare professional.

Breast-feeding

The vaccine is considered safe for breastfeeding mothers.

Storage

Store at 2 to 8 degrees Celsius. Do not freeze. Protect from light.

Formulations

• Inactivated poliovirus vaccine (IPV)
• Oral poliovirus vaccine (OPV)

Dosage

Children: Paediatric dosing for reduced medications should also be individualized and referenced from established guidelines or pharmacological texts, as specific doses are not universally applicable.

Adults: Dosage for reduced medications must be determined based on individual patient needs, taking into account the specific medication and clinical scenario. Refer to relevant clinical guidelines or pharmacological references for exact dosages.

Mechanism of action

The mechanism of action for a reduced form of medication typically involves a decrease in the pharmacological activity of the drug. This may occur through alterations in the drug's structure that decrease its binding affinity to its target receptors, or through metabolic pathways that enhance the breakdown of the drug, leading to a lower concentration in the system.

Pharmacodynamics

Pharmacodynamics of reduced medications generally indicate a lower efficacy in terms of therapeutic effects compared to their standard counterparts. This may result in a broader therapeutic window, reducing the risk of adverse effects, but it may also necessitate careful monitoring of clinical outcomes to ensure therapeutic effectiveness.

Pharmacokinetics

Pharmacokinetics of reduced medications would typically reflect changes in absorption, distribution, metabolism, and excretion. Reduced forms may have altered bioavailability, with slower absorption rates or modified distribution volume, leading to a prolonged half-life. The metabolism may also be affected, with a potential for increased clearance rates due to reduced active components.

Pregnancy

Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Safety has not been established.

Breast-feeding

Use with caution. Monitor for potential side effects in nursing infants.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Tetanus prophylaxis
• Treatment of tetanus infection
• Management of tetanus symptoms

Dosage

Children: Refer to the specific guidelines for tetanus immunoglobulin and other supportive treatments as per clinical protocols.

Adults: Refer to the specific guidelines for tetanus immunoglobulin and other supportive treatments as per clinical protocols.

Mechanism of action

The tetanus toxin binds to the presynaptic membrane of motor neurons and is transported retrogradely to the spinal cord, where it interferes with neurotransmitter release, particularly inhibiting the release of glycine and gamma-aminobutyric acid (GABA), leading to unopposed motor neuron activity and resultant muscle rigidity and spasms.

Pharmacodynamics

Tetanus toxin is one of the most potent toxins known, with effects that can manifest within hours of exposure. The toxin's ability to block inhibitory neurotransmitter release results in a state of continuous muscle contraction, known as tetany. The clinical presentation of tetanus includes trismus (lockjaw), muscle rigidity, and autonomic instability, among others.

Pharmacokinetics

The pharmacokinetics of tetanus toxin are complex due to its high potency and the nature of its action. Following entry into the body, the toxin binds to nerve endings and is internalized, leading to its effects on neurotransmitter release. The half-life of the toxin is not well defined as it does not circulate freely in the bloodstream but acts locally at the neuromuscular junction. Recovery from the effects of the toxin may take weeks to months, depending on the severity of the infection and the treatment provided.

Adverse effects

• Pain at the injection site
• Fever
• Fatigue
• Headache
• Nausea

Precautions

• Ensure patient is up to date with vaccinations
• Monitor for allergic reactions post-vaccination
• Consider history of neurological disorders

Pregnancy

Tetanus vaccination is considered safe during pregnancy and is recommended to protect both the mother and the newborn.

Breast-feeding

Tetanus vaccination is safe during breastfeeding and does not affect the nursing infant.

Storage

Store in a refrigerator at 2–8 degrees Celsius. Do not freeze.

Formulations

• Tetanus toxoid vaccine

Indications

• Diphtheria prophylaxis
• Tetanus prophylaxis
• Pertussis prophylaxis (when combined with other vaccines)

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations for pediatric immunization with toxoids.

Adults: Refer to specific guidelines for each toxoid vaccine, as dosing may vary based on the type of vaccine and individual patient factors.

Mechanism of action

Toxoids work by stimulating the immune system to produce antibodies against the toxin without causing disease. When administered, the immune system recognizes the toxoid as a foreign substance and generates a specific immune response. This includes the production of immunoglobulin G (IgG) antibodies that can neutralize the active toxin if the individual is exposed to the bacteria in the future.

Pharmacodynamics

The pharmacodynamics of toxoids involve the activation of the adaptive immune response. After vaccination, dendritic cells present the antigen to T cells, which then help B cells differentiate into plasma cells that produce specific antibodies. The presence of these antibodies provides immunity against the toxin by neutralizing its effects, thereby preventing the disease associated with the original bacterial toxin.

Pharmacokinetics

Toxoids are typically administered via intramuscular or subcutaneous injection. Following administration, they are gradually taken up by antigen-presenting cells, which then process and present the toxoid to T cells. The immunogenic response can develop over several weeks. The duration of immunity can vary, necessitating booster doses to maintain adequate antibody levels over time.

Adverse effects

• Local reactions at the injection site, such as pain, swelling, or redness.
• Fever.
• Fatigue.
• Headache.
• Allergic reactions in rare cases.

Precautions

• Use with caution in individuals with a history of severe allergic reactions to a vaccine component.
• Monitor patients for allergic reactions post-vaccination.

Pregnancy

Toxoids are generally considered safe during pregnancy; however, consultation with a healthcare provider is recommended.

Breast-feeding

Toxoids are considered safe for use during breastfeeding.

Storage

Store in a refrigerator at 2-8°C. Do not freeze. Protect from light.

Formulations

• Diphtheria toxoid
• Tetanus toxoid
• Pertussis toxoid

Dosage

Children: Refer to specific drug information for paediatric dosing guidance.

Adults: Refer to specific drug information for dosing guidance.

Mechanism of action

The mechanism of action for drugs classified under types varies widely depending on the specific drug. Generally, they may function by inhibiting specific enzymes, blocking receptors, or modulating biological pathways to achieve their therapeutic effects.

Pharmacodynamics

Pharmacodynamics for types of drugs varies significantly depending on the specific medication. In general, pharmacodynamics describes the relationship between drug concentration and effect, including the drug's efficacy, potency, and duration of action. Common dynamics include receptor binding, post-receptor effects, and the drug's influence on physiological functions.

Pharmacokinetics

Pharmacokinetics involves the absorption, distribution, metabolism, and excretion (ADME) of drugs within the body. For various types of drugs, absorption may occur via oral, intravenous, or other routes, distribution is influenced by protein binding and tissue permeability, metabolism typically occurs in the liver, and excretion occurs primarily via renal pathways. Specific parameters such as half-life, bioavailability, and clearance rates depend on the particular drug type.

Indications

• Prevention of infectious diseases such as measles, mumps, rubella, hepatitis B, influenza, and human papillomavirus (HPV)
• Travel vaccinations for diseases endemic to certain regions
• Vaccination for at-risk populations, such as those with compromised immune systems or specific occupational exposures

Dosage

Children: Dosage varies by vaccine type and age; refer to the BNF for Children for specific dosing information.

Adults: Dosage varies by vaccine type and indication; refer to specific guidelines for each vaccine.

Mechanism of action

Vaccines work by mimicking an infection. They introduce a harmless component of a pathogen (antigen) to the immune system, prompting the body to produce an immune response. This includes the generation of antibodies and memory cells that provide long-term immunity. Upon subsequent exposure to the actual pathogen, the immune system is primed to respond more rapidly and effectively.

Pharmacodynamics

The pharmacodynamics of vaccines involves the activation of both humoral and cellular immunity. Vaccines stimulate B cells to produce antibodies against the pathogen, while T cells are activated to destroy infected cells. This dual response helps to establish immunological memory, which enables a faster and more robust response upon re-exposure to the pathogen.

Pharmacokinetics

Vaccines are administered via various routes, including intramuscular, subcutaneous, and oral. After administration, the antigens are presented to antigen-presenting cells, which activate T cells and stimulate B cell proliferation and differentiation. The half-life of vaccine-induced immunity varies depending on the type of vaccine, with some providing lifelong immunity and others requiring booster doses to maintain protection.

Contra-indications

• Severe allergic reaction (anaphylaxis) to a component of the vaccine
• Severe immunocompromised state for live attenuated vaccines

Adverse effects

• Local reactions at the injection site (pain, redness, swelling)
• Fever
• Fatigue
• Headache
• Muscle pain
• Joint pain
• Nausea

Interactions

• Immunosuppressive medications may reduce vaccine efficacy
• Concurrent administration of some vaccines may require spacing to optimize immune response

Precautions

• History of allergic reactions to vaccines or vaccine components
• Pregnancy (specific vaccines may be contraindicated)
• Moderate to severe acute illness with or without fever

Pregnancy

Consult healthcare provider. Some vaccines are contraindicated during pregnancy, while others are recommended.

Breast-feeding

Generally considered safe, but consult healthcare provider regarding specific vaccines.

Storage

Store in a refrigerator at 2-8°C. Do not freeze. Protect from light.

Formulations

• Liquid suspension for injection
• Lyophilized powder for reconstitution