haemophilus influenzae type b vaccine

Action and Spectrum

Actions and spectrum: 

Action: 

• Stimulation of Immune Response: The Hib vaccine contains a part of the haemophilus influenzae type b bacterium, known as the polysaccharide capsule. When a person is vaccinated, their immune system recognizes this component as foreign and produces antibodies to fight against it. 
• Memory Cells Formation: In addition to antibodies, the vaccine promotes the formation of memory cells in the immune system. These memory cells “remember” the characteristics of the Hib bacterium, providing long-term immunity. 

Spectrum: 

• Prevention of Hib Infections: The Hib vaccine is effective in preventing invasive diseases caused by haemophilus influenzae type b. These diseases include meningitis, pneumonia, epiglottitis, and septic arthritis, which can be severe and sometimes life-threatening, particularly in young children. 
• Reduction of Hib Transmission: By vaccinating individuals against Hib, the spread of the bacteria is reduced in the community. This not only protects vaccinated individuals but also contributes to herd immunity, providing indirect protection to those who may not be vaccinated, such as infants who are too young to receive the vaccine. 

Drug Interaction

Adverse Reaction

Frequency defined 

HbOC (HibTITER): fever 2.2%, erythema (3.3%) 

PRP-T (ActHIB, OmniHIB): drowsiness (57.5%), Irritability (72.6%), tenderness (46.3%), fever (20.1%), induration (22.5%), diarrhea (4.4%), anorexia (15.3%) 

DTP + HbOC (TETRAMUNE): irritability, tenderness, swelling, fever, erythema 

Irritability (10-70%), fever (0.5-18%), drowsiness, anorexia erythema (0.4-2.2%), tenderness 

PRP-OMP (PedvaxHIB): swelling (2.5%), fever (18.1%), erythema (2.2%) 

PRP-D (ProHIBiT): tenderness (12%), irritability (14%), drowsiness (8%), fever (2%), vomiting (7%) 

Frequency not defined 

Fever 

Pain 

Rash 

Diarrhea 

Injection site redness 

URI 

Crying 

Irritability 

Sleepiness 

Anorexia 

Vomiting 

Otitis media 

Post marketing Reports 

Angioedema 

Facial edema 

Guillain-Barre syndrome 

Hypersensitivity 

Hypotonia 

Lethargy 

Malaise 

Seizure 

Skin discoloration 

Anaphylactoid reactions 

Erythema multiforme 

Febrile seizure 

Headache 

Hyporesponsive episodes 

Injection site abscess 

Lymphadenopathy 

Mass 

Shock 

Urticaria 

Black Box Warning

Black Box Warning: 

there is no specific black box warning associated with the haemophilus influenzae type b vaccine. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Severe Allergic Reaction (Anaphylaxis): A severe allergic reaction to a previous dose of the Hib vaccine or any of its components is a contraindication. This includes a severe allergic reaction to diphtheria toxoid, as some Hib vaccines are combined with other vaccines. 
• Severe Allergic Reaction to a Vaccine Component: Individuals with a known severe allergy to any component of the Hib vaccine, such as latex or other ingredients, should not receive the vaccine. 
• Encephalopathy Following a Previous Dose: If an individual experienced encephalopathy (brain disease or damage) within 7 days of a previous dose of a pertussis-containing vaccine, the Hib vaccine may be contraindicated. This is a precaution, and the decision to administer the vaccine would depend on the individual’s specific circumstances and expert consultation.

Caution: 

• Moderate or Severe Acute Illness: If an individual is moderately or severely ill at the time of vaccination, healthcare providers may choose to delay vaccination until the person has recovered.  
• History of Guillain-Barré Syndrome (GBS): While there is no conclusive evidence linking the Hib vaccine to an increased risk of Guillain-Barré Syndrome (GBS), some healthcare providers may exercise caution in individuals with a history of GBS or a family history of GBS. 
• Previous Hypersensitivity Reaction: Individuals who have experienced a mild hypersensitivity reaction (such as hives) to a previous dose of the Hib vaccine or any of its components may still be able to receive the vaccine. However, those with a history of severe allergic reactions may need further evaluation and caution. 
• History of Intussusception: There is no evidence linking the Hib vaccine to intussusception, a type of bowel obstruction. However, healthcare providers may consider the individual’s medical history, and in cases of a previous episode of intussusception, they may weigh the risks and benefits of vaccination. 
• Thrombocytopenia or Bleeding Disorders: Individuals with a history of thrombocytopenia (low platelet count) or bleeding disorders may need careful consideration before receiving vaccinations. The decision may depend on the severity of the condition and consultation with a healthcare provider.

Comorbidities: 

• Immunocompromised Conditions: Individuals with conditions that weaken the immune system, such as HIV/AIDS, leukaemia, or other immunodeficiencies, are at an increased risk of severe infections. The Hib vaccine is particularly important for these individuals to protect against invasive Hib disease. 
• Sickle Cell Disease: The sickle cell disease or other hemoglobinopathies are more susceptible to severe infections, including invasive Hib disease. The vaccination is recommended to decrease the risk of Hib-related complications. 
• Asplenia or Splenic Dysfunction: Individuals with asplenia (absence of the spleen) or significant splenic dysfunction are at an increased risk of severe bacterial infections, including Hib. The vaccine helps protect against Hib-related complications in this population. 
• Cochlear Implants: The cochlear implants are at a higher risk of developing Hib infections. The vaccination is recommended to decrease the risk of invasive disease. 
• Chronic Diseases: Certain chronic conditions like diabetes mellitus, may increase the risk of severe infections. Vaccination with the Hib vaccine is recommended for individuals with chronic diseases. 

Pregnancy / Lactation

Pregnancy consideration: pregnancy category: C 

Lactation: excreted into human milk: unknown  

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.   
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

haemophilus influenzae is a conjugate vaccine designed to protect against the infections caused by haemophilus influenzae type b bacteria. The vaccine contains a part of the Hib bacterium’s outer coating, the polysaccharide capsule, conjugated to a carrier protein. This conjugation enhances the immune response, especially in infants, by promoting the production of antibodies.

Upon vaccination, the immune system recognizes the polysaccharide component as foreign, leading to the generation of specific antibodies. These antibodies not only help in eliminating the bacteria but also create immunological memory, providing long-term protection. The Hib vaccine has proven highly effective in preventing invasive Hib diseases, such as meningitis and pneumonia, in young children.  

Pharmacodynamics: 

• Stimulation of Immune Response: The Hib vaccine contains a specific component of haemophilus influenzae type b, the polysaccharide capsule. This capsule is conjugated to a carrier protein to enhance the immune response. Upon administration of the vaccine, the immune system recognizes the polysaccharide as foreign, leading to the activation of B cells. 
• Antibody Production: B cells are stimulated to produce antibodies, particularly IgG antibodies, specific to the Hib polysaccharide. This process is essential for the humoral immune response against Hib. 
• Memory Cell Formation: The vaccine promotes the formation of memory B cells, which “remember” the specific characteristics of the Hib bacterium. These memory cells persist in body and can rapidly mount an immune response upon re-exposure to Hib. 
• Long-Term Immunity: The primary goal of the Hib vaccine is to establish long-term immunity against haemophilus influenzae type b. The immune response is generated by vaccine provides protection against invasive diseases caused by Hib, such as meningitis and pneumonia. 
• Herd Immunity: The widespread administration of the Hib vaccine contributes to herd immunity, protecting not only vaccinated individuals but also reducing the transmission of Hib within the community. This indirect protection benefits those who may not be vaccinated, such as infants too young to receive the vaccine. 

Pharmacokinetics: 

• Absorption: The Hib vaccine is administered via intramuscular or subcutaneous injection. Antigens and adjuvants in the vaccine are introduced directly into the body, through gastrointestinal tract. 
• Distribution: After administration, the components of the vaccine disperse at the injection site and interact with immune cells, particularly antigen-presenting cells (APCs) such as dendritic cells and macrophages. The immune system recognizes the vaccine antigens as foreign, initiating an immune response. 
• Metabolism: The Hib vaccine does not undergo traditional metabolic processes in the way drugs do. Antigens within the vaccine stimulate the production of antibodies and the development of immunological memory. 
• Elimination and excretion: The vaccine components, including antigens and adjuvants, do not undergo renal or hepatic excretion in the same way drugs do. The immune response is triggered by vaccine is the primary outcome, leading to the production of antibodies and immune memory. 

Adminstartion

Administration: 

• Route of Administration: The Hib vaccine is usually administered via intramuscular injection, although subcutaneous administration may be appropriate in certain circumstances. 
• Combination Vaccines: The Hib vaccine is combined with other vaccines to simplify the immunization schedule and reduce the number of injections. For example, it may be combined with vaccines that protect against diphtheria, tetanus, pertussis, hepatitis B, or polio. 
• Catch-Up Vaccination: Children who have missed their scheduled doses or have started the vaccination series later than recommended can usually catch up on the missed doses. 
• Booster Doses: Depending on the specific vaccine formulation and schedule in use, a booster dose may be recommended during the second year of life to ensure long-term protection. 
• Special Populations: Certain populations, such as individuals with specific medical conditions or immunocompromised individuals, may have different vaccination recommendations.

Patient Information Leaflet

Patient information leaflet 

Generic Name: haemophilus influenzae type b vaccine 

Pronounced: (Hee-muh-FIL-us in-flu-ENZ-ee type B vak-seen)  

Why do we use haemophilus influenzae type b vaccine? 

The Hib vaccine has been highly effective in preventing Hib-related meningitis. Hib bacteria can cause pneumonia, a respiratory infection that can be severe, especially in infants and young children. Vaccination helps protect against Hib-related pneumonia.

Hib can lead to epiglottitis, a condition characterized by inflammation of the epiglottis, a flap-like structure at the base of the tongue. Epiglottitis can cause respiratory distress and is a medical emergency.

Hib can cause invasive infections such as septic arthritis, cellulitis, and bloodstream infections. The Hib vaccine helps prevent these serious and potentially life-threatening conditions.