Medical students' risk of infection with bloodborne viruses at home and abroad: questionnaire survey

Introduction

Students in medical schools in Britain and in many other countries have an elective period, in which they are encouraged to pursue medical studies abroad. Many go to developing countries, where a natural enthusiasm to be involved in procedures that they might not experience at home,1 combined with varying standards of supervision, may place students at risk of bloodborne virus infections such as HIV, hepatitis C, and hepatitis B.

At the United Medical and Dental Schools of Guy's and St Thomas's Trust (UMDS; now Guy's, King's College, and St Thomas's School of Medicine), 18consultants act as clinical advisers to students. They are responsible for pastoral care, academic guidance, and advice on electives. One consultant virologist and clinical adviser (AJT) is the nominated officer for the school,2 to whom medical students should come if they have concerns relating to HIV. She is responsible for advising the occupational health department and the clinical advisers on the prevalence of bloodborne viruses worldwide, on reducing the risk of exposure, and on management after exposure.

A document summarising the school's policy on bloodborne viruses, including the education and training of students in avoiding exposure, was produced in 1991and has recently been updated. The importance of guidance for students, not only on their electives, was emphasised by results of the recent Public Health Laboratory Service survey, which showed a high prevalence (15-20%) of markers of current or past infection with hepatitis B in patients attending our trust (E Miller, personal communication). Anonymous screening of antenatal serum samples has shown that our patients also have a relatively high prevalence of HIV infection (0.3-0.5%).3

Each year the occupational health department in conjunction with the department of virology circulates a document to all students with specific advice relating to the risks of acquiring bloodborne viruses while on elective, how to minimise this risk, and what to do if exposed. Prompt reporting and appropriate follow up is emphasised. Since health departments in the United Kingdom now recommend prophylaxis after exposure to HIV,4 students visiting developing countries that have a relatively high prevalence of HIV infection are advised to take with them a six day course of zidovudine, which costs about £40. This allows them to start treatment within an hour of exposure, as recommended, and provides time to seek advice. Monotherapy is regarded as adequate in countries where anti-retroviral drugs are not routinely prescribed. Our guidelines emphasise that the school does not permit students travelling to areas with high prevalence of HIV infection to undertake an obstetrics and gynaecology attachment and that surgery is only permitted in hospitals with high standards of supervision and infection control. All elective proposals and the risks of infection with bloodborne viruses should be discussed with clinical advisers.

We summarise final year students' perception of the advice provided relating to bloodborne virus infections and their experiences during their electives.

Methods

An anonymous questionnaire was sent to 220final year medical students after they completed their electives. A second wave was sent a few weeks later to all students to maximise the response rate. The questionnaire (see website) was designed to seek information on the risks of exposure to and protection against infection with bloodborne viruses, particularly during the elective period.

For the purposes of providing advice to elective students, data from the WHO, UNAIDS, and the Public Health Laboratory Service Communicable Disease Surveillance Centre5^–8 were used to define areas where HIV infection is relatively prevalent—namely, sub-Saharan Africa (most recent estimate of prevalence of HIV up to 40%9); Central America, the Caribbean, and South America (up to 6%9), and South East Asia and the Indian subcontinent (up to 2.4%9). Within these broad areas and within countries themselves, prevalence varies considerably; in some areas, it is increasing rapidly. Furthermore, these figures may underestimate the prevalence of HIV in hospital patients. These areas also have a relatively high prevalence of hepatitis B and hepatitis C. 10 11

Results

All of the 148(67%) students who returned questionnaires had been vaccinated against hepatitis B; 134(91%) had developed an adequate response (>100 mIU/ml). Most students thought that they had received adequate training in phlebotomy (120; 81%) and infection control for bloodborne viruses (106; 72%) during their clinical training.

Sixty five of the 148students (44%) visited areas with a relatively high prevalence of HIV infection (figure). Thirty eight students were aware of this, and of these, 24(63%) visited sub-Saharan Africa, 8(21%) South East Asia or the Indian subcontinent, and 6(16%) Central America, the Caribbean, or South America. All but one of the 38students had discussed their elective with their clinical adviser or the occupational health department, or both, but only 25(66%) had specifically discussed the risks of acquiring bloodborne viruses. Eighteen (47%) of the 38attachments included surgery, trauma, or obstetrics and gynaecology; 16of these students thought that they had been well supervised. Despite the school's policy, two students had obstetrics and gynaecology attachments in areas of Africa with a particularly high prevalence of HIV infection (Zimbabwe and Uganda/Sudan). Both students had discussed their elective with the occupational health department and their clinical adviser, but neither the students nor their clinical advisers had considered the issue of bloodborne viruses. Both of these students thought that they had been well supervised during their attachments.

Number of visits by medical students to different parts of the world during their electives. Some of the 148 students surveyed visited more than one area

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Twenty seven of the 65(42%) students who visited areas with a relatively high prevalence of HIV infection were unaware of this; 24of these (89%) visited South East Asia or the Indian subcontinent and 3(11%) Central America, the Caribbean, and South America. All but two had discussed their elective with their clinical adviser or the occupational health department. Only 6(22%) had specifically discussed the risk of acquiring bloodborne viruses. Seven students (26%) had studied surgery and thought that they were well supervised. None had studied trauma or obstetrics and gynaecology.

None of the 27students visiting areas that were not perceived to have a high prevalence of HIV infection took zidovudine with them, and relatively few took a medi-kit (8; 30%) or latex gloves (4; 15%); 19(70%) found good standards of infection control for bloodborne viruses and 19(70%) thought that they were well supervised (table 1). Only 13of the 38students (34%) who knew that the areas they were visiting had a relatively high prevalence of HIV infection took zidovudine, 24(63%) took a medi-kit and 20(53%) gloves; only 20(53%) found good standards of infection control for bloodborne viruses but 27(71%) thought that they were well supervised.

Three of the four students with percutaneous or mucosal exposures to blood or other body fluids while on elective were in areas of relatively high HIV endemicity. Only one reported the incident (table 2) It is unclear from the questionnaire whether the student visiting South Africa received an exposure from an HIV positive patient and if the course of zidovudine was completed. Forty four of the 148respondents (30%) had received at least one such exposure during the rest of their clinical training and 33(75%) had not reported these.

Discussion