HIV Transmission

HIV Transmission

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 (HBVHCV) 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.

Principles of Infection Control

The infections acquired in health care setting can be greatly minimized by observing some simple precautions. The broad principles of infection control include the following:

  • Infection control measure: Each institution should establish an appropriate infection control (IC) policy and programme. A mechanism should be set up for planning, implementing, monitoring and evaluation of the IC programmes. Preventive measure are essential and very cost-effective, but are often overlooked and considered unnecessary by health care workers. Medical institutions are encouraged to set up an IC programme suitable for its resources
  • Hand washing is the most simple and cost-effective measure and must be encouraged. Disinfectants should be prepared and used according to the guidelines. Antimicrobials should be prescribed rationally according to guidelines to reduce bacterial resistance and side effects.
  • Patients: A patient should not be admitted into a hospital unless it is absolutely necessary and he/she should be discharged as early as possible, to reduce the risk of infection. Patients with low immunity, or those with other predisposing factors to infections should be nursed with special care. Patients with communicable disease such as cholera should be isolated as appropriate to reduce the risk of transmission to others
  • Environment: Health care facilities should be kept clean and void of virulent organisms by proper house keeping. Cleaning of premises and room floors with water and detergent is recommended. Cleaning with a disinfectant is usually not necessary unless there is a spillage with potentially infectious material. Architectural design of a health care facility should permit good ventilation. Extra-measures to decontaminate air in a health care setting is costly and has limited value in infection control. Positive or negative pressure ventilation is indicated in certain areas, but again is expensive and is not superior to practices which ensure a clean and hygienic environment. Proper waste disposal, water treatment, disinfection and sterilization of equipment can reduce the risk of infection among patients, health caretakers and community.
  • Agents: Microorganisms responsible for infections in health care setting may originate from patients, the environment or health care workers. Those sources of infections are to be identified, and specific measures must be taken appropriately to prevent their spread.

Risk of HIV Transmission to Health Care Workers (HCWs)

The transmission through blood and body fluids, organs, tissues, and contaminated material in health care settings is not much though this likely mode of transmission is responsible for apprehensive behaviour of health care workers towards HIV infected people and AIDS cases. Transmission of HIV in health care settings can occur due to following ways :

Patient to health care worker transmission

HIV transmission from patient to health care worker can occur when the health care worker is exposed to the HIV infected blood e.g.

  1. Patenteral exposure, such as needle-stick injury.
  2. Through mucous membrane contact, such as a splash of blood into the health care worker’s eye or mouth.
  3. Through mucous membrane contact, such as a splash of blood into the health care worker’s eye or mouth.
  4. Non-intact skin contact such as splash of blood on to open wounds or broken skin due to dermatitis, acne or cuts or abrasions of skin.

The risk of health care worker of acquiring HIV infection during the course of health care delivery is possible though unlikely. The risk is primarily related to percutaneous (sharp injury) exposure like needle stick injury and has been reported to be less than 0.5%. The HIV cannot enter the body through intact skin but can do so through intact mucous membrane.

The most common way in which health care workers are exposed to HIV is through accidental exposure to sharp objects.

Nearly all cases of HIV transmission to health care workers have occurred through preventable accidents. These are needle-stick injuries, cut from broken blood collection tubes.

Patient-to-Patient transmission

Patient-to-patient spread of HIV infection is usually by an indirect route. This transmission can occur through contaminated needles, syringes and instruments.

Patients can also be infected when they receive contaminated blood or blood products.

Health Care Worker to Patient Transmission

Although theoretically this is possible, however, chances of it occurring are almost nil. Thus, HIV infected health care workers are not considered a risk to patients during routine work activities.

Infection control in health care setting consists of

  1. Barrier precautions (Universal precautions)
  2. Aseptic precautions
  3. Decontamination
  4. Disposal of infective waste
  5. Barrier precautions (Universal Precautions) in relation to blood, body fluids, tissue and organs.


  1. All blood and body fluids to be assumed infections.
  2. Check the continuity of skin by alcoholic rub.

Hand Washing

Hands and other parts of the body that have been contaminated with blood and body fluids must be washed thoroughly with soap and water. Hands should also be washed immediately after removal of protective gloves and in between handling of patients.

Gloves, Masks, Eye Protector and Gowns

Health care workers should wear gloves for all direct contact with blood and body fluids. When gloves are not available, other methods should be used to prevent direct contact with blood; for example, forceps, towel gauze or, if these are not availale, any material such as a plant leaf may be employed to hold a blood stained needle or syringe in rural conditions. If gloves are not disposable, they should be disinfected, washed and sterilized after contact with each patient. When injuries from sharp instruments are possible e.g. when they are being cleaned, extra-heavy duty (rubber) gloves should be used and the instruments should be handled with extreme care.

During procedures in which there may be splashing of blood e.g. during surgery or child birth, the eyes nose and mouth should be protected with a face shield or mask and eye glasses. Suitable plastic sheet should be worn inside gowns.

Mouth-to-mouth resuscitation

Although HIV has been recovered from saliva, the virus is present in very small numbers, less than 1 virus per millitires (ml). There is no conclusive evidence that saliva can be involved in HIV transmission. Always create barrier by using gauze piece while giving mouth to mouth resuscitation.

Cleaning and Decontaminating Spills of Blood or Other Body fluids

In case of a blood/body fluid spill do the following:

  1. Cover the spill with absorbent material, such as gauze cotton, newspaper, cloth.
  2. Pour the disinfectant fluid over the spill starting peripherally to the centre.
  3. Leave the disinfectant fluid for at least ten minutes.
  4. Clean the area after wearing gloves.

Precautions in Relation to Laboratory Specimens

  1. Always wear gloves when handling and processing specimens of blood and other body fluids.
  2. Always collect and transport only in screw cap leak proof containers/bottle
  3. Take care to avoid contamination of outer surface of the containers while transporting samples.
  4. Under no circumstances mouth pipetting should be permitted (Hb estimation.) Westergren method of measuring ESR should be replaced by wintrobe technique where no mouth pipetting is required.
  5. All open wounds on hands and arms of laboratory worker should be covered with a waterproof dressing, preferably, the person should not handle blood or any body fluids.
  6. Hands should always be washed with soap and water immediately after exposure to specimens in laboratory procedures.

    Aseptic Precautions

    1. It is important to restrict injections. Administer parenteral thereapy only if alternative effective oral therapy is not possible.
    2. Use Sterilized needles/syringe for every injection/immunization
    3. Chemical disinfection must not be used for sterilization of needles and syringes
    4. Both autoclaved reusable reusable and pre-sterilized disposable needles and syringes are equally safe.

    If above precautions are always strictly observed, the risk of transmission of HIV through injections and other skin piercing procedures can be greatly minimized.

    Sterilization and Disinfection

    Sterilization is a process of freeing an article from all living organisms including bacterial, fungal spores and viruses. The most dependable method of sterilization in health care setting is moist heat (steam) under pressure utilizing different types of autoclaves.

    A high level of sterilization can be achieved instruments at a temp. of 121 oC at 15 Ibs/sq inch pressure for 15-20 minutes in specially modified pressure cooker (WHO/UNICEF type). Remember all skin and mucous membrane piercing instruments needles, lancets, scalpels, scissors etc.) and equipment coming in contact with blood and mucous membrance must be sterilized before use.

    High Level Disinfection

    High level of disinfection is a process of destroying all micro organism, however, some spores may survive particularly if initially present in large numbers. This can be achieved by:


    Completely immersing instruments in boiling water for 10 minutes. This is a simple and reliable method of freeing all article from most of the pathogenic microorganisms in situations where sterilization by autoclaving is not possible.

    Chemical Disinfectants

    Following chemicals are approved for use as ‘hospital disinfectants’ in recommended dilution to achieve high level of disinfection. Commonly used disinfectants are:

    1. Ethanol – 70% (700 gm/litre)
    2. Glutaradehyde? – 2% (Available commercially as Code:)
    3. Household bleach?? – 1% solution (Available in market as 3.5% ready made solution Polar. Dilute it with 2.5 volumes of tap water to give 1% solution)
    4. Sodium Hypochlorite? – 1% solution
    5. Hydrogen peroxide?? – 3% solution
    6. Lysol – 2.5% solution
    7. Savlon – 5.0%
    8. Dettol – 4.0%


    • Instruments that require sterilization or disinfection should bethoroughly cleaned before being exposed to disinfectants and the manufacturer’s instruction for use of disinfectant should followed.
    • A solution of Sodium hypochlorite prepared daily is inexpensive, effective and easily available disinfectant. Concentration ranging from 0.1 to 2.0 per cent of available chlorine are effective, depending on the amount contamination.

    Handling of Soiled Linen

    All the linen soiled with blood/body fluid should preferably be dipped into 1% household bleach/sodium hypochlorite for half and hour before washing.

    Management of parenteral and mucous membrane exposure of personnel to blood and body fluid: In case of an accidental exposure with contaminated blood or body fluids the following care should be taken:

    1. Allow the accidental wound to bleed and then
    2. Promptly wash the exposed surface with running tap water adequately.
    3. Clean the area with soap and water.
    4. In case of splashing of blood/body fluids into the eyes and silicon contact lenses, if any. Wash eyes gently with water or saline, keeping the eyes open, wash contact lenses also. Clean and disinfect the contact lenses before reuse.
    5. If blood gets into the mouth, spit it out and rinse your mouth with water several times.
    6. Any of the above incidences should be notified to the physician for risk assessment, treatment, referred for HIV testing and counselling. Establish the HIV status of the person with whose blood/body fluid the exposure wash caused.

    Disposal of Infected Waste

    In the health care setting all the potentially infected waste should be appropriately disposed off. Safaiwalas should always wear gloves and apron when handling waste.

    The infected waste in Health care setting can be disposed off by:

    1. Burning-Incineration is a sophisticated method of burning the waste.
    2. Deep Burial with bleach or lime.

    Waste Method of Disposal
    1. Liquid wastes, blood fluids, Suction fluids, excretions secretions, placenta Should be buried in deep pit by covering with blenching powder or lime.
    2. Soild wastes, dressing, laboratory and pathology wastes, menstrual pads Burning Deep Burial
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