[Vaccination against hepatitis B possibly indicated for elderly institutionalized mentally handicapped persons with isolated anti-HBc positivity of the prevaccination serum].

OBJECTIVE

To determine whether vaccination against hepatitis B may be omitted in persons with isolated positive anti-HBc.

DESIGN

Prospective study using control groups. SETTING'S: Heeren Loo-Lozenoord, Ermelo, the Netherlands.

METHOD

Twenty-six older residents (group P) with isolated anti-HBc positivity (HBsAg negative and anti-HBs < 10 IU/l) were given hepatitis B vaccine (3 doses); 16 matched controls (group C1) lacking hepatitis B markers, received a primary vaccination (3 doses), 8 controls (group C2) with a immune status based on infection in the past received vaccination (3 doses) and 27 controls (group C3) were given a booster vaccination (1 dose) after vaccination 7 years earlier. The anti-HBs response was measured 0, 1 and 7 months after the first vaccine dose. An anamnestic response was defined as a fourfold rise of anti-HBs after one dose of vaccine or--in the absence of an anti-HBs titer in the prevaccination serum--a response > or = 10 IU/l after one dose of vaccine. A primary response was defined as an anti-HBs response > or = 10 IU/l after giving 3 vaccines, while the criteria for an anamnestic response were not met.

RESULTS

In the isolated anti-HBc group (P) and in the corresponding control group (C2) 15 and 12.5%, respectively, showed an anamnestic response; the majority reacted with a primary response or did not respond at all. The subjects given a primary vaccination (C1) responded in 62.5% with a primary response while those vaccinated earlier (C3) responded in 92.6% with a fourfold rise of anti-HBs.

CONCLUSIONS

The anti-HBs response to vaccination in older mentally handicapped persons is delayed and there is a reduced chance of development of a protective anti-HBs titer. The majority of individuals with isolated anti-HBc showed a primary response. In these persons vaccination should not be omitted, especially if there is a risk of hepatitis B.