The potential exposure of firefighters to blood borne infectious diseases is similar, if not greater, to that of health care providers. Any and all occupational exposures to blood and body fluids should be approached as urgent medical concerns with life and death significance. Specific exposures of concern to first responders would include percutaneous (i.e., passage through the skin by puncture) and permucosal (blood splashed on the surfaces of mucous membranes) exposures to infected blood and body fluids. As such, it is prudent that fire fighters be familiar with the recommendations set by the Centers for Disease Control and Prevention. In June of 2001, the CDC published their latest recommendations for the management of health-care personnel (HCP) who have occupational exposure to blood and other body fluids.

Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to Human Immunodeficiency Virus and Recommendations for Postexposure Prophylaxis

The following is a discussion of the CDC’s recommendations. In all cases, one should remember that exposure prevention remains the primary strategy for reducing occupational blood-borne infections such as HBV, HCV or HIV. Universal precautions should be used, as much as is possible, whenever there is a potential of exposure to blood or body fluids.

Not to be ignored, people should be aware of non-occupational exposures, which may in fact be of equal or greater importance as occupational exposures. Non-occupational exposures include social behaviors such as sexual activity and drug abuse. All sexually active people not in monogamous relationships should use condoms – even though they are not effective 100 percent of the time.

Definitions

Hepatitis: Hepatitis is a term describing inflammation and disease of the liver. There are two major categories of hepatitis: acute and chronic. Acute hepatitis describes the onset of symptoms over a short period of time after infection. Chronic hepatitis describes a condition whereby the liver inflammation continues for more than six months. In some cases, hepatitis may lead to liver failure. There are many known causes of hepatitis, including chemical and infectious agents. Hepatitis B and Hepatitis C are two different viruses that cause hepatitis. Some of the signs and symptoms of hepatitis include: jaundice (yellow skin or eyes,) fatigue, abdominal pain, weight loss, lack of appetite, nausea, vomiting, weakness, muscle aches and low-grade fever.

HIV/AIDS: Human Immunodeficiency Virus is the virus responsible for the development of Acquired Immunodeficiency Syndrome. By infecting a particular subset of immunity cells (CD4 T cells,) the virus leads to decreased immunity of the host, resulting in opportunistic infections that may be fatal.

Magnitude

The latest available date, from the IAFF Annual Death and Injury Survey, demonstrate that one in 32 fire fighters was exposed to a communicable disease such as hepatitis or HIV in 1998. There is limited data regarding the actual infection rates of fire fighters with hepatitis B, C and HIV.

Some surveys report the prevalence of HCV infection among first responders, including paramedics and emergency medical technicians, as ranging between 1.3-3.2%, with the age- and sex-adjusted prevalence similar to those of the general population.

Hepatitis B

The risk of infection is directly correlated with the degree of contact with blood in the workplace and the status of the source person. The highest risk for infection is found in people exposed via a break in their skin to contaminated blood of a person who is positive for both Hepatitis B surface Antigen (HBsAG) and Hepatitis B e Antigen (HBeAG) – portions of the virus that are responsible for the disease. The HBV virus can be found in several body fluids, such as breast milk, bile, feces, saliva, semen and sweat. However, the highest HBV titers of all body fluids, and the most important, are found in blood.

Post Exposure Prophylaxis (PEP):
Antibodies are one part of a human’s immunity. In general, humans who are exposed to foreign organisms (e.g., bacteria, viruses) will produce antibodies in order to fight those organisms and destroy them. Once antibodies are produced, the immune system can produce even more antibodies upon further exposure. In a sense, the immune system has a ‘memory’ of the foreign organism.

The idea of vaccination relies on the capacity of the immune system’s “memory” of a foreign organism. A small dose of an organism, small enough so that actual disease is not achieved, will produce an immune response and the development of antibodies. After the organism is destroyed, the body will stop making antibodies to fight it, but it will still have a “memory” of that organism. Upon further exposure, even if at high doses, which could produce disease, the immune system will be able to produce enough antibodies to control the organism, destroy it, and thereby avoid disease.

Naturally, there are cases in which people never had a vaccination or an exposure to a specific organism. They are thus at a higher risk of developing disease, because their immune system may not be able to produce enough antibodies to fight the organism. However, there is a medical treatment in such situations. Medical centers have stores of collected, preformed antibodies that they can give patients who don’t have antibodies themselves. These antibodies are also called immunoglobulins.

When the administration of Hepatitis B Immunoglobulin is indicated, it should be administered as soon as possible after exposure, ideally within 24 hours. In the occupational setting, multiple doses of Hepatitis B Immunoglobulin (antibodies to Hepatitis B) initiated within one week following percutaneous (through the skin) exposure to HBsAG-positive blood provides an estimated 75 percent protection from HBV infection. The Hepatitis B Vaccine should also be administered as soon as possible, and may be given at the same time as the immunoglobulins, but at a different site.

Vaccination against HBV
Over 100 million people in the US have been vaccinated as of 2000. In fact, OSHA stipulates that vaccinations must be offered to workers with risk for exposure. It is heartening to know that around 95% of all fire fighters are in fact vaccinated against HBV.

The Hepatitis B Vaccine is administered as a series of three injections, separated in time, into the deltoid muscle. 1 – 2 months after completing the series, a person may be tested for response by checking for anti-HBV antibodies. Non-responders to vaccination should be counseled about re-vaccination (they have a 30 – 50 % chance of responding to a second 3-dose series) and about any precautions they should take.

Any blood or body fluid exposure sustained by an unvaccinated, susceptible (non-immunized) person should lead to the initiation of the hepatitis B vaccine series.

(The above reflects information from: Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to HBV, HCV, and HIV and Recommendations for Postexposure Prophylaxis Vol 50, No RR11;1 06/29/2001)

HIV/AIDS

Risk of transmission after percutaneous (through the skin) exposure to HIV-infected blood is approximately 0.3 percent, and after a mucous membrane exposure is approximately 0.09 percent. The more blood one is exposed to, the greater the risk. An appropriate medical provider should evaluate within hours any person exposed to HIV.

Post Exposure Prophylaxis (PEP) for HIV

Most occupational exposures to HIV do not result in the transmission of HIV. Thus, the potential toxicity of PEP must be carefully considered in the risk: benefit evaluation for treatment. Approximately 50 % of patients experience some side effects, which include, but are not limited to: nausea, fatigue, headache, lack of appetite and skin problems. In up to 33 % of cases, the symptoms may be severe enough that PEP is halted. There are potentially also some very serious life-threatening effects that people should appreciate, especially because the exposed patient being treated may in fact not be infected with HIV.

Biological plausibility supports the argument that infection can be prevented or ameliorated by using antiretroviral drugs. Systemic (whole body) infection with HIV does not occur immediately, leaving a brief window of opportunity during which postexposure antiretroviral intervention might modify or prevent viral replication. In theory, early PEP may limit the proliferation of virus in the initial target cells or lymph nodes.

There is evidence that specific agents currently used for prophylaxis are efficacious. Animal studies have inherent problems of extrapolating to human response. Still, animal studies have shown that larger viral doses on exposure decreased the efficacy of prophylaxis. Furthermore, delaying initiation, shortening the duration, or decreasing the antiretroviral dose of PEP, individually or in combination, decreased prophylactic efficacy. In one human study, ZDV alone was associated with a reduction in the risk of HIV infection by approximately 81 percent.

In some cases, PEP may fail in preventing HIV infection. Reasons for apparent failure include, but are not limited to: exposure to a strain of HIV that is resistant to the specific medication given; exposure to a high titer of virus or large amount of blood; delay in initiation of PEP or inadequate duration of PEP.

If the decision to treat had been made, PEP should be initiated as soon as possible – ideally within an hour of exposure. Still, the interval after which no benefit is gained from PEP for humans is undefined. Therefore, if appropriate, PEP should be started even after 36 hours. If the source of exposure is determined to be HIV negative, PEP should be discontinued. The typical duration of PEP for HIV is 4 weeks long.

There are three classes of antiretroviral agents that are used in the treatment of HIV infection. All work by trying to inhibit the replication of new virus from being formed and infecting new cells. These include: nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs,) and protease inhibitors (PIs.) A physician, knowledgeable in the area of HIV/AIDS should make the actual choice of medication, with the concordance of the patient.

The emotional aspect of an exposure to HIV may be substantial, and should not be ignored. Thus, access to providers knowledgeable about occupational HIV transmission and who can deal with the many concerns an HIV exposure might generate for the exposed person is an important element of post-exposure management.

Specific recommendations to HIV exposure should include measures to prevent secondary transmission – the transmission of the virus from the exposed individual to others. These recommendations are important especially during the first 6-12 weeks post-exposure, a time period during which most HIV-infected individuals will convert to HIV+. The recommendations include: sexual abstinence or the use of condoms; refraining from donating blood, plasma, organs, tissue or semen.

Things to remember:

  • In the case of any acute illness following exposure, the affected individual should consult a physician.
  • Knowledge about the efficacy of drugs used for PEP is limited
  • Combination drug regimens are often used because of increased effectiveness and concerns about drug-resistant viruses
  • Data regarding toxicity of antiretroviral drugs in persons without HIV infection are limited
  • Serious adverse events have occurred in persons taking PEP
  • Any or all drugs for PEP may be declined or stopped by the exposed person