Universal precautions

The only infection control precautions which need to be taken against HIV in any job or any walk of life are the same as the usual proper standards of good infection control in that situation, known as 'universal precautions'.

HIV is known to have similar modes of transmission to Hepatitis B but with one crucial difference – HIV is much less infectious than Hepatitis B. Consequently, infection control procedures which protect against Hepatitis B will also protect against HIV.

Universal precautions are the most effective way to ensure that the risk of HIV infection is minimised. The principle is the same as that of safer sex, where universal precautions such as condoms are far more effective at reducing risk than subjective methods such as `choosing carefully'.

The dangers of relying upon screening

It is often suggested that the screening of patients in hospitals, the screening of health care workers, or the adoption of barrier precautions only against those identified either as HIV–positive or as identifiable members of risk groups, will prevent further cases of HIV infection. This is a fallacy for several reasons:

• It is impossible to identify everyone who is HIV–infected by HIV testing because of the `window period' between infection and the appearance of antibodies
• It is impossible to identify everyone who is HIV infected on the basis either of questions about past behaviour or presumed membership of a `risk group'
• It is impossible to judge the need for universal precautions on the basis of historical, retrospective knowledge about HIV prevalence in a particular area. For instance, many doctors and midwives were surprised to learn the extent of HIV prevalence amongst pregnant women in London as a result of anonymised seroprevalence studies. Although these data confirmed the extent of HIV infection amongst pregnant women, it could not have protected any health care workers at risk from blood during birth. On the other hand, universal precautions, if implemented at that time, would have protected midwives and doctors.

Universal precautions to protect patients

Even with very uneven adherence to universal precautions in the developed world, there have been only a handful of cases where a surgical procedure seems to have to led to infection (see Transmission from dentists and dental equipment, above). This suggests that universal precautions, coupled with the modification of working practices on the part of infected health care workers, are likely to be largely successful in protecting patients. Guidelines concerning the working practices of HIV–infected health care workers can be found in Employment.

Difficulties in adopting universal precautions

We continue to hear regular reports in the medical press of the un–systematic way in which precautions are adopted by health care workers, and the link between a failure to follow established infection control procedures and accidents which may result in occupational HIV infection. Accidents will always happen in health care settings, but the risk of accidents can be reduced by careful planning.

Universal precautions are least likely to be practised when:

• Patients are perceived to be `low risk'.
• There is a lack of adequate time to complete procedures.
• Barrier precautions such as glove use interfere with manual dexterity.