Compliance and immunogenicity of two hepatitis B vaccination schedules in sex workers in Belgium.
OBJECTIVE
To compare the coverage for the third dose and the compliance to two hepatitis B vaccination schedules: 0,1,4 versus 0,1,6 months, in commercial sex workers (CSW) in Belgium; to compare the immunogenicity of the actually administered schedules.


METHODS
In seven health centres in Belgium, hepatitis B vaccination was offered free of charge to CSW. In a randomised, prospective study a commercialised hepatitis B vaccine (Engerix-B 20mcgr) was offered according to one of both schedules. After complete vaccination, bleeding was performed to assess immunogenicity.


RESULTS
Between June 2003 and September 2004, 615 non-immune CSW were enrolled, of whom 52% in the 0,1,4 month schedule (n=322). Coverage of the third dose was 57% overall, 59% (0,1,4) and 54% (0,1,6), respectively. Age, the health centre and drug use significantly influenced the compliance and the coverage of dose 3, whereas the planned vaccination did not. When comparing the immunogenicity results as a function of the actually administered vaccination schedule, immune responses did not significantly differ between CSW receiving the third dose 4-6 months and those receiving it at least 6 months after the first dose. In total, 19 persons (8%) were not protected after a full vaccination course (anti-HBs <10IU/L). Two health centres measured markedly lower anti-HBs levels.


CONCLUSIONS
In this highly mobile at-risk population, a 0,1,4 month schedule is more easy to offer and confers equal protection within a shorter period of time. We therefore propose this 0,1,4 month schedule to vaccinate CSW in the future.
Wouters
K
K
Centre for the Evaluation of Vaccination, University of Antwerp, Belgium.
Leuridan
E
E
Van Herck
K
K
Van Ardenne
N
N
Roelofs
I
I
Mak
R
R
Prévost
C
C
Guérin
P
P
Denis
B
B
Van Damme
P
P
D000328:Adult; D000367:Age Factors; D001530:Belgium; D005260:Female; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011446:Prospective Studies; D011477:Sex Work; D019966:Substance-Related Disorders
D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines