Hepatitis B vaccination usually requires a series of 3 injections over a 6-month period. A single 'booster' vaccine may not be adequate for antibody response.
However, if you have completed two full rounds of the Twinrix vaccine and currently still do not have detectable antibody levels, then you would be termed a non-responder.
Hepatitis B vaccine non-responders are considered to still be at risk of hepatitis B infection, so if you are exposed to potentially infected blood or body fluids, you would be advised to attend a healthcare facility as early as possible for an injection of hepatitis B immunoglobulin (HBIG) to reduce the risk of infection.
You should also speak to a healthcare provider at that point about post-exposure prophylaxis for other potential blood-borne infections.
