Study: Gaps persist in HBV immunizations
HCWs need to remain vigilant
About one in four health care workers who are offered the hepatitis B vaccine decline to take it, according to a study by the Centers for Disease Control and Prevention.1 Although the occupational risk of acquiring hepatitis B has declined dramatically since the 1980s, health care workers still need to be vigilant about vaccination, says Ian Williams, PhD, MS, chief of the Epidemiologic Research and Field Investigations Team in the Division of Viral Hepatitis at the CDC.
A cross-sectional study of 300 U.S. hospitals found that 75% of health care workers offered the vaccine received it, says Williams. Yet there were differences based on demographics and job type. For example, among staff physicians and nurses the coverage rate was 81% — an indication that a significant number are declining the vaccine. Hepatitis B vaccination was even lower among phlebotomists and nurses' aides (71%).
"You'd think it should be 100% and it's not," says Williams. "We've come an incredibly long way, but we're still not at 100%. We should be."
In the 1980s, about 12,000 health care workers acquired hepatitis B each year from blood and body fluid exposures. Currently, CDC hepatitis experts estimate that there are fewer than 200 new cases among health care workers each year.
The incidence of new infections among health care workers is now lower than in the general population. Yet health care workers need to re-main vigilant about protecting themselves, says Williams. "A lot of people have forgotten that hepatitis B was a substantial occupational risk," he says.
Hepatitis B is significantly more transmissible than HIV; the likelihood of acquiring HBV after an exposure ranges from 3% to 30%, depending on the source patient's e antigen status and viral load. The virus also can survive at least a week in dried blood and poses a danger from surface contamination.2
Vaccinating health care workers during their training, such as in nursing or medical school, is an effective way to ensure that they are protected, says Williams. About 90% of children and infants are vaccinated against hepatitis B, and that cohort will be protected when they become adults, he notes.
Although HBV titers decline over time, "cellular memory" provides long-lasting protection of at least 20 years. "It doesn't look like booster doses are necessary at this point, but it's certainly something we're looking at very carefully," he says.
The CDC recommends testing health care workers for antibody status within one to two months after completing a three-dose series of HBV vaccine. A small portion — 5% or 10% — will not respond and will need a second three-dose series. Anyone who tests negative after the second series is considered a non-responder to the vaccine.
Newly identified non-responders should be tested for chronic HBV infection, the CDC recommends. Following an exposure, they should receive two doses of hepatitis B immune globulin. (If the health care worker had received only one series of the HBV vaccine, they should receive one dose of immune globulin and be revaccinated.)3 "The major determinant of the effectiveness of PEP is early administration of the initial dose of vaccine," the CDC says.4
In its most recent guidance, issued Dec. 8, 2006, the CDC also raises the issue of intradermal vaccination of non-responders: "Intradermal vaccination has been reported to be immunogenic in persons who did not respond to intramuscular vaccination; however, intradermal vaccination is not a route of administration indicated in the manufacturers' package labeling."
In its latest guidance, the CDC says that occupational health programs should:
- identify all staff whose work-related activities involve exposure to blood or other potentially infectious body fluids in a health care, laboratory, public safety, or institutional setting (including employees, students, contractors, attending clinicians, emergency medical technicians, paramedics, and volunteers);
- provide education to staff to encourage vaccination;
- implement active follow-up, with reminders to track completion of the vaccine series among persons receiving vaccination; and
- provide appropriate post-vaccination testing.
References
1. Simard EP, Miller JT, George PA, et al. Hepatitis B Vaccination Coverage Levels Among Health Care Workers in the United States, 2002-2003. Presented at the 2005 annual meeting of the Infectious Diseases Society of America, Sept. 30, 2005.
2. Williams IT, Perz JF, and Bell BP. Viral Hepatitis Transmission in Ambulatory Health Care Settings. Clin Inf Dis 2004;38:1592-1598.
3. Centers for Disease Control and Prevention. Updated U.S. Public Health Service guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for post-exposure prophylaxis. MMWR 2001; 50(RR-11):1-42.
4. Centers for Disease Control and Prevention. A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States. MMWR 2006; 55(RR16):1-25.
About one in four health care workers who are offered the hepatitis B vaccine decline to take it, according to a study by the Centers for Disease Control and Prevention.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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