Typhoid vaccine is a live attenuated vaccine available as an oral and parenteral formulation that induces active immunity against Salmonella typhi.

• The oral vaccine may be advised to adults and children greater than 6 years of age. The vaccine schedule must be finished at least a week before a possible encounter with typhoid bugs.
• The parenteral vaccination can be given to both adults and children who are at least 2 years old.
• At least two weeks should pass after starting the vaccine schedule before any potential contact with typhoid bugs.
• Except for Pakistan, it is not a part of the regular immunisation schedule.

(Pakistan is the first nation to incorporate the typhoid conjugate vaccine (TCV), which is advised by the World Health Organization (WHO), into its regular immunisation programme.). 

• In the United States, Canada, and other countries, its use is limited to:
  • Travelers (especially to typhoid-endemic areas)
  • Exposed individuals (to a household contact with S. typhi fever or a known carrier)
  • Laboratory technicians (with frequent exposure to S. typhi)
• It may also be considered in travelers with achlorhydria, or those receiving antacids, and patients with asplenia (anatomic or functional).

Typhoid Vaccine Dose in Adults

The dose of Typhoid vaccine in the prevention of Typhoid fever:

Oral vaccine:

• Primary immunization:

  • On days 1, 3, 5, and 7, take one capsule every other day for a total of four doses.
  • At least one week should pass between the last of the four doses and the potential exposure.

• Reimmunization (with continued or repeated exposure to typhoid fever):

  • Reimmunization should be done every five years with a full course as mentioned above in the primary immunization.
  • Alternatively, in Canada, reimmunization is recommended with a full course of primary immunization every 7 years.

Intramuscular vaccine:

• provided 0.5 mL at least two weeks prior to the anticipated exposure

• Reimmunization (with continued or repeated exposure to typhoid fever):

  • Typhim Vi:

    • 0.5 mL IM every 2 years (US labeling) or every 3 years (Canadian labeling)

  • Typherix [Canadian product]:

    • 0.5 mL IM every 3 years

Typhoid Vaccine Dose in Childrens

The dose of typhoid vaccine in the prevention of Typhoid fever:

Oral vaccine (Vivotif):

• Children ≥6 years and Adolescents:

  • Primary immunization:

    • On days 1, 3, 5, and 7, take one capsule every other day for a total of four doses.
    • At least one week should pass between the last of the four doses and the potential exposure.

  • Reimmunization (with continued or repeated exposure to typhoid fever):

    • Reimmunization should be done every five years with a full course as mentioned above in the primary immunization.

Intramuscular vaccine (Typhim Vi):

• Children ≥2 years and Adolescents:

  • Primary immunization:

    • provided 0.5 mL at least two weeks prior to the anticipated exposure

  • Reimmunization (with continued or repeated exposure to typhoid fever):

    • 0.5 mL IM every two years for exposure that has occurred more than once.

• Additional Canadian labeling and recommendations:

  • An oral vaccine for Children ≥5 years and Adolescents:

    • Reimmunization with continued or repeated exposure to typhoid fever:

      • Every seven years, a full primary vaccination series should be finished.

  • IM vaccine for Children ≥2 years and Adolescents:

    • Reimmunization with continued or repeated exposure to typhoid fever:

      • Every three years, take a single dose of 0..5 ml of Typhim Vi and Typherix.

Pregnancy Risk Factor C

• It is not recommended for use during pregnancy.
• Typhim Vi suggests that you delay typhoid vaccine until the second or the third trimester, according to the manufacturer.

Typhoid vaccine uses during breastfeeding:

• Breastfeeding is not harmful for the child.
• You can schedule your maternal vaccination.

Typhoid Vaccine Dose in Kidney Disease:

The manufacturer has not recommended any dose adjustment in patients with kidney disease.

Typhoid Vaccine Dose in Liver Disease:

The manufacturer has not recommended any dose adjustment in patients with liver  disease.

Common Side Effects of Injectable Typhoid vaccine Include:

• Central Nervous System:

  • Malaise
  • Headache
  • Generalized Ache

• Local:

  • Tenderness At Injection Site
  • Pain At Injection Site
  • Induration At Injection Site

• Neuromuscular & Skeletal:

  • Muscle Tenderness

• Miscellaneous:

  • Fever

Less Common Side Effects of Injectable Typhoid vaccine Include:

• Dermatologic:

  • Pruritus

• Gastrointestinal:

  • Vomiting
  • Nausea

• Local:

  • Swelling At Injection Site
  • Injection Site: Erythema At Injection Site

• Neuromuscular & Skeletal:

  • Myalgia

• Miscellaneous:

  • Fever Greater Than 100 To 101 Degrees

Less Common Side Effects of Oral Typhoid vaccine Include:

• Central Nervous System:

  • Headache

• Dermatologic:

  • Skin Rash

• Gastrointestinal:

  • Diarrhea
  • Abdominal Pain
  • Vomiting
  • Nausea

• Miscellaneous:

  • Fever

Contraindication to Typhoid vaccine Include:

• Allergy to any vaccine component
• Patients with acquired or congenital immunodeficiency are not advised to receive the oral vaccine.
• Acute febrile illness
• Contraindicated for pregnant women, those with acute gastrointestinal conditions, and those suffering from inflammatory bowel diseases is the oral typhoid vaccination

Warnings and precautions

• Anaphylactoid reactions and hypersensitivity reactions
  • Parenteral vaccinations can cause anaphylactic or hypersensitivity reactions.
  • Immediate treatment may include fluid resuscitation and epinephrine 1 mg/ml that should be available during the vaccination settings.
• Syncope
  • The injection vaccine can cause syncope, which is usually experienced within 15 minutes of vaccination.  Serious injuries like a skull fracture or a brain haemorrhage may result from this.
• Acute illness:
  • Patients with severe or moderately severe infections should delay vaccinating.
  • Patients with mild infections should be vaccinated immediately.
  • Patients with severe gastrointestinal disease, diarrhea, or vomiting should avoid oral medication.
• Bleeding disorders:
  • Patients with bleeding disorders such as thrombocytopenia should not receive the parenteral vaccine.
  • Intramuscular administration can cause bleeding or hematoma formation.
  • Patients with hemophilia and von Willebrand diseases may receive the vaccine shortly after the administration of Factor VIII, von Willebrand factor, or other similar therapy.
• Typhoid fever
  • The vaccine is only partial effective so it is important to advise the person not to ingest contaminated foods or water.
  • It should not be used for typhoid fever.

Typhoid vaccine: Drug Interaction

Monitor:

• Monitor the patient for syncope and anaphylactic reactions for 15 minutes after the administration of the vaccine.
• Patients who develop syncope or have seizure-like activity associated with syncope, the patient should be maintained in a supine or Trendelenburg position.

How to administer Typhoid vaccine?

Parenteral administration:

• Only intramuscular administration of the vaccine should be used for parenteral formulations.
• The deltoid muscle receives one injection of the vaccine totaling 0.5 mL (25 mcg).

Gluteal administration should be avoided.

Avoid the intravascular administration of the vaccine (Typhim Vi and Typherix)

• Additionally, it shouldn't be combined with other injections or immunizations.
• While administering the vaccine, make the patient lie down or get the patient seated to prevent syncope. Additionally, distinct syringes must to be used for every injection.
• Patients with a high risk of bleeding should be encouraged to see their primary care provider.
• Patients with hemophilia may receive the vaccine shortly after the administration of Factor VIII or other similar therapy.
• A fine needle (23 gauge or smaller) should also be used to administer the vaccine to patients at risk, and firm pressure should be applied to the injection site for at least two minutes.
• The risk of injection site hematoma should be explained to the patient prior to the vaccination.
• Similarly, patients on anticoagulants may be at risk of local hematoma formation and should be treated appropriately prior to the administration of the vaccine.

Oral typhoid vaccine:

• The capsule should be swallowed whole with a cold or lukewarm beverage (≤37˚C/98.6˚F)
• It should not be chewed or opened.
• Advise the individual to take the vaccine one hour prior to a meal.
• Avoid alcohol intake one hour before or two hours after administration of the vaccine as alcohol may alter the enteric coating.

Mechanism of action of Typhoid vaccine:

• Active immunity to Salmonella typhi is induced by Typhoid vaccine. 
• Live attenuated Typhoid vaccine includes the use of S. Typhi Ty21a strain, which lacks UDP-4-galactose Epimerase.
• Oral vaccines confer local immunity in the intestinal tract. 
• It will be necessary to provide a full lipopolysaccharide to halt the progression of a dangerous illness.
• The bacterial polysaccharide, which is low in amount, causes antibody formation while the strain remains virulent. 
• The intracellular accumulations of metabolic intermediates means that the bacteria cells can lyse before becoming virulent.

Efficacy: The cumulative efficacy of the injectable vaccine is 55% and the oral vaccine 48% respectively over the 3 to 5 year period.

The beginning of action: After completing the oral course and two weeks of administering one dose of the parenteral formula, antibodies against Salmonella Typhi form.

Time: The immunity to salmonella typhi is more than five years long after oral vaccination, two years after administration of the parenteral Typhim Vi vaccine and three years after receiving the parenteral Typherix vaccine.

International Brands of Typhoid vaccine:

• Typhim Vi
• Vivotif
• Typherix
• Vivotif
• Typbar
• Typh-Vax
• Typherix
• Typhim Vi
• Typhim VI
• Typhoral
• Typhovax
• Tyrix Vi
• Vivotif
• Vivotif Berna
• Vivotif Berna Capsule
• Vivotif Oral
• Vivotif Oralt Vaccin
• Zerotyph

Typhoid Vaccine brands in Pakistan: