How medical students in their pre-clinical year perceive their own hepatitis-B-virus status: the results of a study in a Thai medical school.

In 2000 all of the medical students of the Faculty of Medicine at Chulalongkorn University in Bangkok who were then in their pre-clinical year were interviewed about their hepatitis-B-virus (HBV) status. Of the 215 interviewees, 125 (58.2%) claimed to know their HBV status. Seventy (32.6%) of the subjects assumed they were immune because they had already been vaccinated against the virus, 32 (14.9%) claimed to have natural immunity following exposure to the virus, and 14 (6.5%) reported that they were HBV carriers. Another five (2.3%) of the subjects said they had been tested for HBV and found seronegative and the remaining four subjects (1.9%) who said they knew their status declined to give any more details. The 90 subjects who did not know their status were all offered HBV screening, and 62 agreed to be tested, both for the surface antigen of the virus (HBsAG) and antibody to the viral core (anti-HBc). These tests revealed that 37 subjects were seronegative (negative for both HBsAg and anti-HBc), 11 appeared to have natural immunity (negative for HBsAg but positive for anti-HBc) and the other 14 were carriers (positive for HBsAg but negative for anti-HBc). Four of the 14 carriers were also positive for the HBV 'e' antigen (HBeAg), indicating that they were highly infectious. Medical students form a high-risk group for infection with blood-borne pathogens, including HBV. That more than 40% of the pre-clinical students in the present study did not know their HBV status and fewer than 50% had been vaccinated against the virus are therefore causes for concern. Those students entering Thai medical schools for the first time clearly need to be better educated about hepatitis B and to be encouraged to be vaccinated before they begin any clinical practices.