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HIV Transmission

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Prevention of HIV Transmission in Health Care Settings

What We Mean by Health Care Setting

Health care settings include hospitals, out-patient departments, clinics, nursing homes, dispensaries or any other place in home or community where medical care is provided for curative, preventive, promotive or rehabilitative purposes.

The problem of Infection Acquired in the Health Care Setting


Infections acquired in the health care setting are the infections which patients acquire from health facilities and these were not being incubated at the time of entry.

Symptoms may appear during or after admission. They also apply to infections among health care workers and visitors who acquired at home while providing home care.

The diagnosis of infections acquired in the health care setting is the same as other infections i.e., it is based on clinical evidence of the disease with laboratory evidence to support in certain circumstances, provided that it can be provided that the causative organism(s) is/are acquired during the period when health care was provided.

Risk of Infections Acquired While Providing Health Care

The overall risk of acquiring infection in the health care setting increases in the presence of the following risk factors:

  • Patient factors: extreme ages, malnutrition, immune deficiency, injuries etc.

Infection Acquired in Health Care Settings

  • Microbial factors: Agents present in high concentration, high level of virulence or the presence of new organisms in the health care environment.
  • Environmental factors: Level of contamination with causative organisms and medical interventions that may facilitate their transmission for example surgery, invasive diagnostic or therapeutic procedures to susceptible persons.

The major concern at the present time is the risk of acquiring HIV in the health care setting. Patients are infected mainly by transfusion of contaminated blood or blood products. Infection through contaminated medical equipment is also possible, although the risk is very low. Health care workers have been infected percutaneously, mainly by sharp injuries i.e. contaminated needles, scalpels and broken glass. Skin and mucosal contact with HIV contaminated fluids has been incriminated in a few cases. The same mechanism of transmission applies to hepatitis B and C (HBV, HCV) infections but the risk is much higher due to the high prevalence of HBV carriers and the infectivity of the virus.

Risk of Transmission of Blood Borne Viruses to Health Care Workers

Human immunodeficiency virus (HIV)

  1. Percutaneous exposure – 0.4%
  2. Mucocutaneous exposure – 0.05%
  3. Hepatitis B virus (HBV)
  4. Percutaneous exposure – 9-30%
  5. Hepatitis C virus (HCV)
  6. Percutaneous exposure – 3-10%

The setting up of an effective infection control programme requires information on occupational exposure, the prevalence of disease and factors related to it. Such information can be obtained through surveillance by assessing the magnitude of the problem and detecting change over time in the incidence. Prevalence will reflect the magnitude of the problem at a specific time or period, and this can be calculated by counting the number of patients who have acquired infection in the health care setting at the time of survey divided by the total number of patients present at that time. It is relatively simple and more reliable when compared with other methods, but it does not reflect changes in disease incidence unless repeated surveys have been done. Surveillance data are essential for developing and revising infection control policies and procedures.

Infections in the health care setting can occur in the form of outbreaks, when evidence shows that there is a cluster of a particular type of infection in a certain group of people or a significant increase in the incidence of an infection or a site of infection. Attempts to contain an outbreak should begin with an investigation to find the cause of the outbreak. Data on time, place, and persons should be collected and analyzed. Samples should be collected as appropriate for microbiological investigations. Environmental samples are usually not valuable unless there is evidence that they are relevant. Empirical intervention measures have to be implemented initially and specific measures must be carried out when the cause of the outbreak has been identified. Outbreak often arise from faulty techniques, procedures, defective disinfections or sterilization and contamination of pre-sterilized equipment.

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