Academic journal article Bulletin of the World Health Organization

Practical and Affordable Measures for the Protection of Health Care Workers from Tuberculosis in Low-Income Countries

Academic journal article Bulletin of the World Health Organization

Practical and Affordable Measures for the Protection of Health Care Workers from Tuberculosis in Low-Income Countries

Article excerpt

Risk of TB infection among health care workers in industrialized countries

Background

Before the advent of effective antituberculosis medication, the risk of tuberculosis (TB) among health care workers, particularly those who worked in TB sanatoria, was high. After 1950, this risk declined substantially in industrialized countries because of the decreasing incidence of the disease and the availability of effective antituberculosis chemotherapy. However, since 1985 there have been a number of reported outbreaks of nosocomial TB, particularly in the USA, and the disease has once again become a serious occupational hazard for health care workers. In 1993, a total of 3.2% of TB cases in the USA occurred among such workers (1), and many of these cases were occupationally acquired.

There are several reasons for the upsurge of nosocomial TB in industrialized countries (Table 1). Over the last decade there has been a resurgence of the disease in Europe and the USA. The incidence of TB increased by 20% in the USA over the period 1985-92, by 20% in Denmark over the period 1986-92, by 27% in Italy over the period 1988-92 and by 28% in Spain over the period 1990-92 (2). Many medical staff with working experience of TB have retired from the health service, leaving a new generation of physicians for whom it is an uncommon disease and low on the list of differential diagnoses. Infection control practices were therefore relaxed or simply not followed in many hospitals because of the perception that TB was no longer important. The advent of multidrug-resistant TB, particularly in the USA, encouraged its spread within hospitals -- not because patients with multidrug-resistant TB are more infectious than those with the drug-sensitive disease, but because first-line antituberculosis drugs are inadequate for its treatment, and patients infected with multidrug-resistant strains may remain infectious longer. Currently, the greatest risk of nosocomial TB transmission is to immunocompromised patients or staff, especially those infected with the human immunodeficiency virus (HIV). Health care workers and patients infected with HIV are more susceptible to TB, and once infected may not be able to contain the infection and may rapidly develop overt disease (3, 4).

Table 1: Reasons for the increase in nosocomial TB transmission in industrialized countries

* Resurgence of TB * Poor hospital infection control practices * Multidrug-resistant TB * HIV infection

The "at risk" health care worker

Nurses were the first occupational group who were identified to be at increased risk for TB and probably have the highest rate of infection and disease of all health care workers (5). This is not surprising, in view of the prolonged and often close contact between hospital nurses and patients. Physicians, particularly those aged 20-35 years and specialists in internal medicine, experience substantial rates of tuberculous infection and disease (6, 7). Specialists in respiratory medicine have higher rates of infection than those in other areas (8), probably because of the extra risk associated with performing bronchoscopy or caring for ventilated patients in intensive care units. Pathologists represent a further risk group. A study in Japan found a high incidence of TB among pathologists and pathology technicians, with the highest rates being among those who performed or assisted at autopsies (9).

Laboratory staff may become infected with TB either through accidental inhalation or inadvertent inoculation. In a review of the global literature, TB was reported to be the sixth most common occupationally acquired infection among laboratory workers 10), and it has been estimated that laboratory workers have a two to nine times higher risk of contracting TB than the general public (11). Although all these categories of health care worker are at risk regardless of their immune status, those infected with HIV are at much higher risk; for example, one review reported that 8 of 17 health care workers with multidrug-resistant TB were HIV positive (12). …

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