Code	Mode of infection
1	homo/bisexual
10	Sexual abuse
2	injecting drug user
3	(1+2)
4	haemophiliac
5	transfusion, non-haemophilia related
6	heterosexual contact
7	(6+2)
8	Perinatal
9	Sexual contact (homo/hetero not specified)
90	other, (specify)
99	unknown