10 Questions and Answers About Blood Borne Infections And Vaccination....Extracted From Dental Secrets SE By Stephen T.Sonis, D.M.D., D.M.Sc.

01. What are universal precautions?

Universal precautions a concept of infection control, assume that any patient is potentially infectious for  a number of bloodborne pathogens. Blood, blood-derived products, and certain other fluids that are contaminated with blood  are considered infectious for human immunodeficiency virus (HIV), hepatitis B  virus (HBV), hepatitis C virus (HCV), and other bloodborne pathogens. Standard precautions are procedure-specific, not patient-specific. In dentistry, saliva is normally considered to be blood-contaminated.

02. What is the chain of infection?

The chain of infection refers to the prerequisites for infection (by either direct or indirect contact):

1. A susceptible host

2. A pathogen with sufficient infectivity and numbers to cause infection

3. An appropriate portal of entry to the host (e.g., a bloodborne agent must gain access to the bloodstream, whereas an enteric agent must enter the mouth [tract]).

03. Which factor is easiest to control: agent, host, or transmission?

Agent and host are more difficult to control than transmission. Standard precautions are directed toward interrupting the transfer of microorganisms from patient to health care worker and vice versa.

04. What is one of the single most important measures to reduce the risk of transmission of microorganisms?

Hand washing is one of the most important measures in reducing the risk of transmission of microorganisms. Hands should always be thoroughly washed between patients, after contact with blood or other potentially infective fluids, after contact with contaminated instruments or items, and after removal of gloves. Gloves  also  play  an  important  role  as  a  protective  barrier  against  cross-contamination and reduce the likelihood of transferring microorganisms from health care workers to patients and from environmental surfaces to patients. A cardinal rule for safety is never to touch a surface with contaminated gloves that will subsequently be touched with ungloved hands.

05. What are standard procedures?

Standard procedures are designed to reduce the risk of transmission of microorganisms from both recognized and unrecognized sources of infection in hospitals. They are a combination of universal precautions and body substance isolation precautions and apply to blood, all bodily fluids (whether or not they contain blood), non intact skin, and mucous membranes.

05. Is exposure synonymous with infection?

No. An exposure is a contact that has a reasonable potential to complete the chain of infection and result in disease of the host.

06. What are hepatitis B and delta hepatitis?

Hepatitis B is one of most common reportable diseases in the United States. HBV is transmitted through blood and sexual fluids: it is highly transmissible because of the large numbers of virus in the blood of infected persons (about 100 million per ml). Delta hepatitis is caused by a defective virus (hepatitis D virus [that relies on HBV for its pathogenicity and can infect only in the presence of HBV. HBV and HDV co-infection, however, results in a fulminant course of liver disease.

07. Why is hepatitis B vaccination so important?

HBV is the major infectious occupational hazard to health care workers. Transmission has been documented from providers to patients and vice versa. In 1982, a vaccine became available to provide protection from HBV infection. The first-generation vaccine was plasma-derived, but the vaccine in current use is genetically engineered. The safety and efficacy of the vaccine are well established, and there is no current recommendation for booster doses. Furthermore, protection from I-JBV also confers protection from HDV.

08. If you are employed in a dental practice, who pays for the HBV vaccine—you or your employer?

If an employee may be exposed to blood or other potentially infectious fluids during the course of work, it is the obligation of the employer to offer and pay for the series of vaccinations. The employer is not required to pay titer test costs because this test is not recommended by the United States Public Health Service (USPHS), the agency on which OSHA relies for advice.

09. What if I refuse the vaccination?

In most states, you have a right to refuse the vaccination. You should realize, however, that without the HBV vaccination series or evidence of previous infection you remain at risk for acquiring HBV infection. Because OSHA considers the HBV vaccination one of the most important protections that a health care worker can have, the agency requires the employee to sign a waiver if the vaccination is refused. Signing the waiver does not mean that, if you change your mind in the future, the employer does not have to pay.

10. What is the risk of HIV transmission associated with percutaneous mucous membrane exposures to blood known to be HIV-positive?

The risk is about 0.3% (1/300) for percutaneous and about 0.09% (1/900) for mucous membrane exposures. Many factors, however, influence the likelihood of transmission. Accumulated data from studies involving health care worker exposures suggest a 0.2—0.4% risk of HIV infection with the worst case scenario of a severe percutaneous injury involving exposure to blood from a terminal HIV patient.