Introduction

Health care workers are at risk of exposure to a variety of infectious diseases which may cause them illness and which may be transmitted from them to other staff and patients. Occupational Health Departments (OHD) that work closely with the infection control department may minimize this risk by maintaining necessary records, performing immunizations, educating staff about risk and prevention, and conducting exposure management and investigations.

Key elements of OH programs

• Assess infection risks to personnel and prioritise preventive measures.
• Implement an ongoing education programme about safety and infection prevention related to the specific risks of work in the facility.
• Determine susceptibility to vaccine preventable diseases and implement an appropriate immunization programme.
• Conduct exposure investigations, including review of post-exposure management.
• Implement surveillance of occupational blood exposures and develop prevention strategies for high-risk practices or departments.

Table 5.1 presents a list of nosocomial infections in patients and employees in health care settings. It is important for local Infection Control Committees and OHDs to review this list and prioritise the allocation of resources for risk reduction strategies in their specific facility. The routes of transmission of each microorganism must be understood before appropriate prevention measures can be selected.

Prevention of infection: General measures

• Keep accurate, easily retrievable occupational health records.
• Screen new employees for a history of communicable diseases. Immunize for vaccine preventable diseases.
• Record needlestick and other injuries in an "accident' log; data on the epidemiology of blood exposures should be analysed periodically to audit practice and identify preventable risks.
• Provide evaluation and guide work restrictions for staff with infectious diseases or exposures.
• Ensure that all staff cover lesions on exposed skin with a waterproof dressing.

Definitions for modes of transmission:

Contact : Includes direct person-to-person contact (e.g., blood from a patient directly into a health care worker's open cut) and indirect contact (transmission from one person to another via an intermediate object such as a health care worker's hands or a device such as a needle).

Droplet: Droplet spread may occur when the infected person and the susceptible host are within about 3 feet of each other. Oral and respiratory secretions may be transmitted into eyes or mucous membranes by coughing, either by direct droplet spread or indirectly by contamination of surfaces subsequently touched by another person.

Airborne: Occurs by dissemination of airborne droplet nuclei (small-particles < 5 microns in size) that may remain suspended in the air for long periods of time.

Common vehicle transmission: Microorganisms transmitted by contaminated items such as food, water, medications, devices, and equipment.

Vectorborne transmission: Requires vectors such as mosquitoes, flies, rats, and other vermin to transmit microorganisms.

Minimal requirements for personnel and patient protection

Preventing the spread of infection often requires us to 'break the chain of infection', i.e., to interrupt the normal routes of transmission.

Contact: Wash hands when they are likely to have been soiled and before beginning care for a new patient. Waterless hand antiseptics are acceptable unless the hands are visibly soiled. For contact with all mucous membranes and non-intact skin, wear gloves that are clean at the time of use. Use sterile gloves for normally sterile body sites. Wear appropriate barriers for the task, e.g., eyewear for spatter and appropriate gloves for contact with all moist body substances. Disinfect all items between patients. Handle all clinical specimens as if known to be infectious. Handle soiled linen and trash to avoid skin contact.

Airborne: Restricting susceptible staff from exposure is the best and often the only prevention strategy for diseases transmitted in whole or in part by air. Common surgical masks provide minimal protection. High efficiency, respirator type masks may offer some protection when in close contact with a coughing patient with tuberculosis. However, they are expensive and often not available. It is not clear if they are useful to protect susceptible staff when there is widespread dissemination of measles or varicella virus.

Bloodborne: Because of potential exposure to hepatitis B virus (HBV) in patient's blood, immunisation is recommended for all healthcare workers who have exposure to blood and body fluids. However, this does not decrease the need to observe safe practices to reduce needlestick injuries and other blood exposures. For example, only re-cap disposable needles using a one-handed technique. Place used sharps in puncture-proof containers before reprocessing or disposal. Use no touch techniques (forceps or gloves) to handle blood or blood contaminated material. Wear gloves for handling sharp items; one layer of latex reduces blood inoculum significantly [1] .

Establish a procedure for reporting blood exposures to the OHD and management actions to be taken. Surveillance for occupational blood exposures can provide data to direct prevention efforts. Routine accident reports may not provide accurate or sufficient information to guide these prevention strategies; therefore focused studies may be required. [2] Such studies in departments where the risk for occupational blood exposures is high have reported that personnel were able to reduce the frequency of exposures more than half by changing practices and increasing barrier precautions [3]. Post- exposure management recommendations for human immunodeficiency virus (HIV) change frequently and are beyond the scope of this chapter, but they are somewhat successful and healthcare facilities should have appropriate policies in place.

The Safe Injection Global Network [4] estimates that approximately 16 billion injections are given annually in the world. Many injections are used unnecessarily when oral medication would be better. In addition, in settings with limited resources, more than half of all injections are given with syringes reused without sterilization or high level disinfection. Studies in China, Pakistan, India, Moldova, Romania, Egypt, African nations and other countries have reported an association between unsterile injections and subsequent HBV, hepatitis C virus (HCV) and HIV infection to be very high. In 2000, contaminated injections caused an estimated 21 million HBV infections, two million HCV infections and 260,000 HIV infections, accounting for 32%, 40% and 5% respectively of new infections [4] .

Although health care personnel are also at risk for exposure to bloodborne pathogens, these figures include only the estimated risk to patients.

Some risks to health care workers can be eliminated by using devices that minimize puncture opportunities; many others can be reduced by infection prevention programs that mandate appropriate use of barrier precautions and safe work practices.

In the Spring of 2003, a newly emerged coronavirus was identified as the cause of Severe Acute Respiratory Syndrome (SARS). By mid-summer, more than 8500 cases had been identified with more than 800 fatalities, most in Asian countries. Approximately 60% were hospital acquired and many occurred in health care personnel. Transmission to health care workers occurred most frequently after unprotected, close contact with symptomatic individuals. Prevention strategies include a high index of suspicion and immediate isolation for patients with systemic viral syndromes that produce fever and cough, especially among people who have traveled to regions that were affected by SARS. Cleaning and surface disinfection in care areas is also important. Personal protective equipment for Standard Precautions, and Contact and Airborne Isolation include hand hygiene, gloves, gowns, and N95 or equivalent respirator.