Wednesday, December 26, 2012

Exposure to Blood: Treatment for the Exposure Part 2

How soon after exposure to a bloodborne pathogen should treatment start?

HBV

Postexposure treatment should begin as soon as possible after exposure, preferably within 24 hours, and no later than 7 days.

HIV

Treatment should be started as soon as possible, preferably within hours as opposed to days, after the exposure. Although animal studies suggest that treatment is less effective when started more than 24-36 hours after exposure, the time frame after which no benefit is gained in humans is not known. Starting treatment after a longer period (e.g., 1 week) may be considered for exposures that represent an increased risk of transmission.

Has the FDA approved these drugs to prevent bloodborne virus infection following an occupational exposure?

HBV

Yes. Both hepatitis B vaccine and HBIG are approved for this use.

HIV

No. The FDA has approved these drugs only for the treatment of existing HIV infection, but not as a treatment to prevent infection. However, physicians may prescribe any approved drug when, in their professional judgment, the use of the drug is warranted.

What is known about the safety and side effects of these drugs?

HBV

Hepatitis B vaccine and HBIG are very safe. There is no information that the vaccine causes any chronic illnesses. Most illnesses reported after a hepatitis B vaccination are related to other causes and not the vaccine. However, you should report to your healthcare provider any unusual reaction after a hepatitis B vaccination.

HIV

All of the antiviral drugs for treatment of HIV have been associated with side effects. The most common side effects include upset stomach (nausea, vomiting, diarrhea), tiredness, or headache. The few serious side effects that have been reported in healthcare personnel using combinations of antiviral drugs after exposure have included kidney stones, hepatitis, and suppressed blood cell production. Protease inhibitors (e.g., indinavir and nelfinavir) may interact with other medicines and cause serious side effects and should not be taken in combination with certain other drugs, such as non-sedating antihistamines, e.g., Claritin®. If you need to take antiviral drugs for an HIV exposure, it is important to tell the healthcare provider managing your exposure about any medications you are currently taking.

Can pregnant healthcare personnel take the drugs recommended for postexposure treatment?

HBV

Yes. Women who are pregnant or breast-feeding can receive the hepatitis B vaccine and/or HBIG. Pregnant women who are exposed to blood should be vaccinated against HBV infection, because infection during pregnancy can cause severe illness in the mother and a chronic infection in the newborn. The vaccine does not harm the fetus.

HIV

Pregnancy should not rule out the use of postexposure treatment when it is warranted. If you are pregnant you should understand what is known and not known regarding the potential benefits and risks associated with the use of antiviral drugs in order to make an informed decision about treatment.

Wednesday, December 19, 2012

Exposure to Blood: Treatment for the Exposure

Is vaccine or treatment available to prevent infections with blood-borne pathogens?

HBV

As mentioned above, hepatitis B vaccine has been available since 1982 to prevent HBV infection. All healthcare personnel who have a reasonable chance of exposure to blood or body fluids should receive hepatitis B vaccine. Vaccination ideally should occur during the healthcare worker's training period. Workers should be tested 1-2 months after the vaccine series is complete to make sure that vaccination has provided immunity to HBV infection. Hepatitis B immune globulin (HBIG) alone or in combination with vaccine (if not previously vaccinated) is effective in preventing HBV infection after an exposure. The decision to begin treatment is based on several factors, such as:
  • Whether the source individual is positive for hepatitis B surface antigen
  • Whether you have been vaccinated
  • Whether the vaccine provided you immunity

HCV

There is no vaccine against hepatitis C and no treatment after an exposure that will prevent infection. Neither immune globulin nor antiviral therapy is recommended after exposure. For these reasons, following recommended infection control practices to prevent percutaneous injuries is imperative.

HIV

There is no vaccine against HIV. However, results from a small number of studies suggest that the use of some antiretroviral drugs after certain occupational exposures may reduce the chance of HIV transmission. Postexposure prophylaxis (PEP) is recommended for certain occupational exposures that pose a risk of transmission. However, for those exposures without risk of HIV infection, PEP is not recommended because the drugs used to prevent infection may have serious side effects. You should discuss the risks and side effects with your healthcare provider before starting PEP for HIV.

How are exposures to blood from an individual whose infection status is unknown handled?

HBV–HCV–HIV

If the source individual cannot be identified or tested, decisions regarding follow-up should be based on the exposure risk and whether the source is likely to be infected with a bloodborne pathogen. Follow-up testing should be available to all personnel who are concerned about possible infection through occupational exposure.

What specific drugs are recommended for postexposure treatment?

HBV

If you have not been vaccinated, then hepatitis B vaccination is recommended for any exposure regardless of the source person's HBV status. HBIG and/or hepatitis B vaccine may be recommended depending on the source person's infection status, your vaccination status and, if vaccinated, your response to the vaccine.

HCV

There is no postexposure treatment that will prevent HCV infection.

HIV

The Public Health Service recommends a 4-week course of a combination of either two antiretroviral drugs for most HIV exposures, or three antiretroviral drugs for exposures that may pose a greater risk for transmitting HIV (such as those involving a larger volume of blood with a larger amount of HIV or a concern about drug-resistant HIV). Differences in side effects associated with the use of these drugs may influence which drugs are selected in a specific situation. These recommendations are intended to provide guidance to clinicians and may be modified on a case-by-case basis. Determining which drugs and how many drugs to use or when to change a treatment regimen is largely a matter of judgment. Whenever possible, consulting an expert with experience in the use of antiviral drugs is advised, especially if a recommended drug is not available, if the source patient's virus is likely to be resistant to one or more recommended drugs, or if the drugs are poorly tolerated.

Wednesday, December 5, 2012

Exposure to Blood: Risk of Infection after Exposure

What is the risk of infection after an occupational exposure?

HBV

Healthcare personnel who have received hepatitis B vaccine and developed immunity to the virus are at virtually no risk for infection. For a susceptible person, the risk from a single needlestick or cut exposure to HBV-infected blood ranges from 6-30% and depends on the hepatitis B e antigen (HBeAg) status of the source individual. Hepatitis B surface antigen (HBsAg)-positive individuals who are HBeAg positive have more virus in their blood and are more likely to transmit HBV than those who are HBeAg negative. While there is a risk for HBV infection from exposures of mucous membranes or nonintact skin, there is no known risk for HBV infection from exposure to intact skin.

HCV

The average risk for infection after a needlestick or cut exposure to HCV-infected blood is approximately 1.8%. The risk following a blood exposure to the eye, nose or mouth is unknown, but is believed to be very small; however, HCV infection from blood splash to the eye has been reported. There also has been a report of HCV transmission that may have resulted from exposure to nonintact skin, but no known risk from exposure to intact skin.

HIV

  • The average risk of HIV infection after a needlestick or cut exposure to HlV-infected blood is 0.3% (i.e., three-tenths of one percent, or about 1 in 300). Stated another way, 99.7% of needlestick/cut exposures do not lead to infection.
  • The risk after exposure of the eye, nose, or mouth to HIV-infected blood is estimated to be, on average, 0.1% (1 in 1,000).
  • The risk after exposure of non-intact skin to HlV-infected blood is estimated to be less than 0.1%. A small amount of blood on intact skin probably poses no risk at all. There have been no documented cases of HIV transmission due to an exposure involving a small amount of blood on intact skin (a few drops of blood on skin for a short period of time).

How many healthcare personnel have been infected with blood-borne pathogens?

HBV

The annual number of occupational infections has decreased 95% since hepatitis B vaccine became available in 1982, from >10,000 in 1983 to <400 in 2001 (CDC, unpublished data).

HCV

There are no exact estimates on the number of healthcare personnel occupationally infected with HCV. However, studies have shown that 1% of hospital healthcare personnel have evidence of HCV infection (about 3% of the U.S. population has evidence of infection). The number of these workers who may have been infected through an occupational exposure is unknown.

HIV

As of December 2001, CDC had received reports of 57 documented cases and 138 possible cases of occupationally acquired HIV infection among healthcare personnel in the United States since reporting began in 1985.