The doctor usually does not determine the titer afterwards: Scientific studies have shown that the vaccination almost always offers babies and children sufficient protection.
Hepatitis B vaccination: This is why the titer is checked in adults
A determination of the titer, i.e. a measurement of the number of antibodies in the blood, is only necessary after a hepatitis B vaccination in adulthood. It has been shown that the vaccination in adults sometimes does not work as well as in children.
Age is not the only factor that determines vaccination success. Certain diseases can also prevent the vaccination from being fully effective. But one thing is clear: the older the vaccinated person, the more likely it is that their immune system will not (or not sufficiently) respond to the vaccination.
The titer is therefore determined in adults after the hepatitis B vaccination. Depending on the measured titer, the further procedure of the doctor differs.
The following table provides an overview of the titer values and their meaning:
| titer | classification | proceed further |
|---|---|---|
| 100 or more IU per liter | adequate vaccination protection | no further vaccination necessary |
| 10 to 99 IU per liter | Low responder (person whose immune system responds too weakly to the vaccination) | an immediate further vaccination, then another control of the titer after four to eight weeks |
| less than 10 IU per liter | Non-responder (person for whom the vaccine has little or no effect) | Test for chronic hepatitis B infection. If negative, further vaccination and then check the titer again after four to eight weeks |
People whose immune systems react only weakly to the vaccination (low responders) may need several further vaccinations until their titer has reached the minimum value of 100 international units (IU) per liter of blood.
According to the official recommendation of the Standing Vaccination Commission (STIKO), up to two vaccination series can follow. A series comprises three vaccination doses, so a total of up to six individual vaccinations are possible. After each dose, the doctor checks the titer with another blood test.
The procedure is similar for people whose immune system does not or hardly responds to the vaccination (non-responders) – with the difference that the doctor must first rule out a chronic infection with hepatitis B viruses.
Because if a person hardly responds to the vaccination, it indicates that their immune system is compromised. So it could be that she is already unknowingly carrying the hepatitis B virus because her immune system cannot fight it.
In this case, the infected person receives antiviral therapy, i.e. treatment that is directed against the virus.
If, on the other hand, no chronic hepatitis B infection can be detected, the doctor will try to increase the antibody titer – and thus the vaccination protection – with further vaccinations. In this case, too, a total of up to six vaccination doses can follow.
If that is not enough, the STIKO does not recommend further vaccinations. Whether these bring anything has not been finally clarified and is controversial among experts.
How often should the titer be checked?
The protection of the vaccine decreases over time, so the antibody titer gradually decreases. How quickly depends, among other things, on the age, gender and state of health of the person and cannot be reliably estimated in advance.
Therefore, regular titer checks are useful in certain cases. In people whose immune system is weakened and who have therefore been vaccinated again against hepatitis B, the examination should be carried out once a year.
Anyone who has a healthy immune system and is vaccinated because of their job, for example, should only have a check-up once every ten years.