Typherix: Typhoid polysaccharide vaccine
Typherix vaccine is given to prevent typhoid fever also known as enteric fever. This is Typhoid Vi polysaccharide vaccine by GSK. This is Salmonella enterica serovar Typhi, S typhi Ty2 strain. This is not a conjugated vaccine.
This vaccine is available as single dose or multidose vial and also single dose prefilled syringe. It contains purified Vi polysaccharide of S. typhi capsular antigen 25 mcg.
|Each 0.5 ml contains|
|Polysaccharides of Salmonella typhi|
(Ty2 Strain) in Single dose pre filled syringe
|The other ingredients are: Phenol and a buffer solution containing sodium chloride, disodium|
phosphate dihydrate, sodium dihydrogren phosphate dihydrate and water for injections
How is Typherix vaccine available?
Typherix vaccine is available as ready to inject liquid form. It is available in pre filled syringe with 0.5 ml injectable single dose. It looks cloudy, the constituents become homogenous when agitated. It is packed in an opaque packet to protect it from light. The sterile single use disposable needle for injection is usually available in the packet.
How is Typherix vaccine stored?
Typherix vaccine is stored at 2-8 degree Celsius. The temperature is maintained with the help of cold chain. The temperature range should be maintained at all stages of the storage and transportation. The vaccine if frozen accidentally should be discarded and should not be used. The vaccine if passed beyond expiry date should not be used and discarded.
How is Typherix vaccine given?
Typherix vaccine is given on anterolateral aspect of thigh intramuscular injection. All the safe injection precautions should be utilized while giving injection. It should not be given subcut or intravenous as the efficacy by these routes is unknown. Those with bleeding tendency may get it subcut the clinical decision by pediatrician is needed.
At what age Typherix vaccine is given?
Typherix can be safely given to all above age 2 years. This is not indicated for routine immunization in USA. For those who are living in countries in Africa, Asia which are endemic for Typhoid enteric fever can be given in routine immunization.
Those who are going to visit these countries shoud take it beforehand visiting these countries.
This is not a compulsory traveler vaccine but it is safe and good to take it befor visiting those countries.
What if some has missed dose of Typherix?
If someone has missed the dose of Typherix should get it earliest as possible. The decision to take vaccine should be taken after consultation with pediatrician. Those children staying in endemic area like South east Asia and Indian subcontinent should get this vaccine. Those planning to visit these regions or other endemic regions should get this vaccine at least 3 weeks before exposure.
How does Typherix vaccine works?
Typherix contains antigens from Vi capsuler polysaccharide antigenof S. typhi capsule. When this vaccine is injected to the host all these antigens are entered into the body. Inside the host these antigens are recognized by the immune system of the host. The immune mechanism to fight against these antigens is developed. When real infection occurs the immune response is rapidly ramped up and the disease is prevented. This is active form of immunization that is host himself/herself develops the immunity by its own mechanism after vaccination. The boosters are needed to maintain the long term immunity as after many years the immunity may wane. This is not the conjugated vaccine. This is polysaccharide vaccine. It is inefficient in inducing immunity in children less than 2 years old. Yet the duration this vaccine provides protection is unknown.
Boosters are definitely needed every 3 yearly.
Safety of Typherix vaccine with other drugs:
As this is killed vaccine it is safe to give the vaccine with most of the other medicines and other vaccine. It is safe if given with other vaccines like MMR, measles and pneumococcal vaccines.
The vaccine if given with other vaccines should not be mixed in same syringe it should be given separately and at separate site.
The vaccine is safe for immunocompromised patients and those with HIV AIDS patients.
The safety of vaccine is not yet established in pregnancy and lactating mothers.
What are side effects after Typherix vaccine?
Typherix vaccine is S. typhi Vi-polysaccharide antigen conjugated to tetanus toxoid.
- Fever may come after the vaccination it may last for 3 days and usually mild to moderate grade. It can be easily controlled with paracetamol oral medicine and sponging. It can be managed at home.
- Injection site pain and swelling may occur after vaccination. It is less as compared to DTwP vaccine. This pain can be managed with paracetamol and cold compression at injection site.
- Irritability may come after vaccination may last for 1-3 days usually subsides by its own.
- Headache may occur after vaccination this side effect can be easily managed with paracetamol and usually subsides by its own.
- Lose motions and vomiting may occur in few patients after vaccination. It can be managed with Oral rehydrating solution and if needed medicine like ondansetron.
- Cough and wheezing.
- Rash and urticaria.
- Joints and muscle pain.
- If patient is allergic to any component anaphylaxis reaction may occur. This is extremely rare side effect but can be life threatening. The facility at which vaccination is given should be equipped with treatment to manage anaphylaxis reaction.
To whom Typherix vaccine should not be given?
Typherix vaccine should not be given to someone if known allergic to any of its components.
This vaccine being polysaccharide vaccine should not be used for below 2 years age, rather Typbar Tcv is preferred which is conjugated vaccine.
The contraindications Of Typherix vaccine are very rare, advice of pediatrician should be considered before any conclusion.
Those with convulsion in past is not a contraindication for this vaccination.
Those with bleeding disorder like haemophilia should plan this vaccine after getting the dose of factor administered. Subcut route should be considered in such patients and clinical discretion of the treating pediatrician is needed.
Cautions with Typherix vaccine
- This vaccine may not protect you 100 percent from enteric fever.
- Other preventive steps for typhoid fever and hand washing is still needed.
- This vaccine may not protect to those who are immuno-compromised and those with advanced stages of HIV AIDS.
- This vaccine is in-effective for those below 2 years age.
- This vaccine protects only against S. typhi but not against S. paratyphi.