Syncope (fainting) can occur following, or even before, any vaccination especially in adolescents as a psychogenic response to the needle injection. This can be accompanied by several neurological signs such as transient visual disturbance, paraesthesia and tonic-clonic limb movements during recovery. It is important that procedures are in place to avoid injury from faints.
It is possible that subjects may be in the incubation period of a hepatitis A or hepatitis B infection at the time of vaccination. It is not known whether Twinrix Adult will prevent hepatitis A and hepatitis B in such cases.
The vaccine will not prevent infection caused by other agents such as hepatitis C and hepatitis E and other pathogens known to infect the liver.
Twinrix Adult is not recommended for postexposure prophylaxis (e.g. needle stick injury).
The vaccine has not been tested in patients with impaired immunity. In haemodialysis patients and persons with an impaired immune system, adequate anti-HAV and anti-HBs antibody titres may not be obtained after the primary immunisation course and such patients may therefore require administration of additional doses of vaccine.
Obesity (defined as BMI ≥30 kg/m2) has been observed to reduce the immune response to hepatitis A vaccines. A number of factors have been observed to reduce the immune response to hepatitis B vaccines. These factors include older age, male gender, obesity, smoking, route of administration, and some chronic underlying diseases. Consideration should be given to serological testing of those subjects who may be at risk of not achieving seroprotection following a complete course of Twinrix Adult. Additional doses may need to be considered for persons who do not respond or have a sub-optimal response to a course of vaccinations.
As with all injectable vaccines, appropriate medical treatment and supervision should always be readily available in case of a rare anaphylactic event following the administration of the vaccine.
Since intradermal injection or intramuscular administration into the gluteal muscle could lead to a suboptimal response to the vaccine, these routes should be avoided. However, exceptionally Twinrix Adult can be administered subcutaneously to subjects with thrombocytopenia or bleeding disorders since bleeding may occur following an intramuscular administration to these subjects (see Dosage & Administration).
Twinrix Adult should under no circumstances be administered intravascularly.
As with any vaccine, a protective immune response may not be elicited in all vaccinees.
Traceability: In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.
Effects on ability to drive and use machines: Twinrix Adult has no or negligible influence on the ability to drive and use machines.