typhoid polysaccharide vaccine

Action and Spectrum

Actions and Spectrum: 

The typhoid polysaccharide vaccine is designed to protect against typhoid fever, which is caused by the bacteria Salmonella enterica serotype Typhi.  

• Antigen Presentation: When the typhoid polysaccharide vaccine is administered, the polysaccharide antigens are recognized by the immune system as foreign. These antigens stimulate the production of antibodies by B lymphocytes. 
• B-Cell Activation: B lymphocytes, or B cells, are activated by the presence of the polysaccharide antigens. This activation leads to the differentiation of B cells into plasma cells, which are responsible for the production of antibodies. 
• Antibody Production: The primary immune response involves the production of antibodies, specifically IgM antibodies, against the polysaccharide antigens. This response provides an initial level of protection. 
• Class Switching: Over time, there may be a class switch in the antibodies produced, leading to the production of IgG antibodies. IgG antibodies are more effective in providing long-term protection and are capable of memory responses upon re-exposure to the pathogen. 

The typhoid polysaccharide vaccine primarily targets Salmonella enterica serotype Typhi, the bacterium responsible for causing typhoid fever. The vaccine is designed to confer immunity against this specific serotype of Salmonella. 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Malaise (4-24%) 

Soreness (16%) 

General aches (1-13%) 

Fever (2-32%) 

Headache (16-20%) 

Induration (5-15%) 

1-10% 

Nausea (<8%) 

Vomiting (1.5%) 

Pruritus (<8%) 

Abdominal pain (6.4%) 

Diarrhea (2.9%) 

Skin rash (1%) 

Myalgia (3-7%) 

<1% 

Diarrhea 

Arthralgia 

Loss of consciousness 

Cervical pain 

Flu-like syndrome 

Abdominal pain 

Perforated jejunum 

Black Box Warning

Black box warning: 

None 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Allergic Reaction: Individuals who have had a severe allergic reaction (anaphylaxis) to a previous dose of the typhoid polysaccharide vaccine or any of its components should not receive further doses. 
• Severe Illness: Vaccination may be postponed in individuals with moderate to severe acute illnesses. It is generally recommended that the person wait until they have recovered before receiving the vaccine. 
• Immunocompromised Individuals: People with severe immunodeficiency conditions or undergoing immunosuppressive therapy (such as chemotherapy or high-dose corticosteroids) may be at risk for reduced vaccine effectiveness. In particular, live attenuated vaccines may be contraindicated in these individuals. 
• Age Considerations: The typhoid polysaccharide vaccine is generally not recommended for children under the age of 2. Alternative vaccines, such as the conjugate typhoid vaccine, may be more suitable for younger age groups. 
• Known Hypersensitivity to Vaccine Components: Individuals with known hypersensitivity or allergy to any component of the typhoid polysaccharide vaccine, including latex (if the vaccine packaging contains latex), should avoid vaccination. 

Caution: 

• Mild Illness: Caution should be exercised in individuals with mild acute illnesses; vaccination may be postponed if the illness is more severe. 
• History of Guillain-Barré Syndrome (GBS): Individuals with a history of GBS or a family history of GBS should exercise caution; discuss risks and benefits with a healthcare provider. 
• Immunocompromised Individuals: Use caution in individuals with severe immunodeficiency; vaccine effectiveness may be reduced. 
• Latex Allergy: Individuals with a known latex allergy should inform their healthcare provider; consider alternative vaccine options without latex. 

Pregnancy / Lactation

Pregnancy consideration: Caution is advised during pregnancy, especially in the first trimester 

Lactation: Excretion of the drug in human breast milk is 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: 

The typhoid polysaccharide vaccine is designed to induce an immune response against Salmonella enterica serotype Typhi, the bacterium causing typhoid fever. Key points in the pharmacology of this vaccine include: 

• Immunogenicity: Vi polysaccharide stimulates B cells, leading to the production of antibodies, primarily IgM initially and IgG later, upon repeated exposure or booster doses. 
• Immune Response: The vaccine elicits a humoral immune response, generating antibodies that circulate in the bloodstream and target the Vi polysaccharide antigen. 
• Memory Response: The immune system “memorizes” the Vi polysaccharide structure, enabling a faster and more effective response upon subsequent exposure to Salmonella Typhi. 
• Booster Doses: Periodic booster doses may be recommended to reinforce and prolong immunity. 

Pharmacodynamics:  

The pharmacodynamics of the typhoid polysaccharide vaccine involves the interaction between the vaccine and the immune system, leading to specific biological effects. Here is a brief overview: 

Antigen Recognition: The vaccine contains purified Vi capsular polysaccharide from Salmonella Typhi. Upon administration, the Vi polysaccharide is recognized by the immune system as a foreign antigen. 

B-Cell Activation: The Vi polysaccharide activates B lymphocytes (B cells) within the immune system. This activation prompts the differentiation of B cells into plasma cells. 

• Antibody Production: Plasma cells are responsible for producing antibodies, primarily of the IgM class initially. Subsequent exposure or booster doses may lead to the production of IgG antibodies, which contribute to longer-term immunity. 
• Humoral Immune Response: The vaccine primarily induces a humoral immune response involving the production of antibodies circulating in the bloodstream. These antibodies are specifically targeted against the Vi polysaccharide antigen. 
• Memory Response: The immune system “memorizes” the characteristics of the Vi polysaccharide, leading to immunological memory. This memory allows for a more rapid and effective response upon re-exposure to Salmonella Typhi. 

Pharmacokinetics: 

Absorption 

The typhoid polysaccharide vaccine is administered by injection, typically intramuscularly. The Vi polysaccharide antigens are introduced directly into the bloodstream. 

Distribution 

The vaccine components, particularly the Vi polysaccharide antigens, are distributed throughout the body via the bloodstream. The antigens stimulate B lymphocytes (B cells) in various lymphoid tissues, including the spleen and lymph nodes. 

Metabolism 

The vaccine does not undergo metabolic processes in the traditional sense since it contains purified polysaccharide antigens. Metabolism, as commonly understood for drugs, involves chemical transformations. In the case of the vaccine, the antigens interact with the immune system to trigger an immune response. 

Elimination and Excretion 

The components of the typhoid polysaccharide vaccine, including the Vi polysaccharide antigens, are not metabolized in the body. Instead, they are cleared from the system as part of the normal immune response. The immune system generates antibodies against the antigens, and these antibodies play a role in the clearance of the antigens from the bloodstream. 

Adminstartion

Administration: 

Intramuscular administration 

The vaccine is commonly administered intramuscularly (IM). Intramuscular injection sites often include the deltoid muscle in the upper arm or the vastus lateralis muscle in the thigh. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: typhoid polysaccharide vaccine 

Why do we use typhoid polysaccharide vaccine? 

The typhoid polysaccharide vaccine is primarily used for the prevention of typhoid fever, a bacterial infection caused by Salmonella enterica serotype Typhi.  

• Travel to Endemic Areas: Individuals planning to travel to regions where typhoid fever is endemic or where there is an increased risk of exposure to contaminated food and water may receive the typhoid polysaccharide vaccine. This includes travelers to certain parts of Asia, Africa, and Latin America. 
• Occupational Exposure: Vaccination may be recommended for people whose occupations involve close contact with potentially contaminated food or water, such as health-care workers, laboratory personnel, and those involved in sewage and sanitation work. 
• Outbreak Control: In the event of a typhoid fever outbreak, the typhoid polysaccharide vaccine may be used as part of public health measures to control the spread of the disease in affected populations. 
• Preventive Measures for High-Risk Individuals: Certain medical conditions or factors that increase an individual’s susceptibility to severe complications from typhoid fever may make them high-risk. In such cases, health-care providers may recommend vaccination with the typhoid polysaccharide vaccine. 
• Military Personnel Deployments: Military personnel deployed to regions where typhoid fever is prevalent may receive the typhoid polysaccharide vaccine as part of routine pre-deployment vaccinations.