SUMMARY: As many as 1 in 5 cases of acute hepatitis B virus (HBV) infection in the U.S. may be attributable to exposure in healthcare settings, especially long-term care facilities, according to research presented last week at the 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010) in Boston.

By Liz Highleyman

To learn more about routes of hepatitis B transmission, Danni Daniels from the Centers for Disease Control and Prevention (CD) and colleagues collected data from surveillance of new HBV infections reported during 2005-2009 by health departments in Colorado, Connecticut, Minnesota, Oregon, 34 counties in New York State, and New York City. They included case patients who met clinical and laboratory criteria for infection, being positive for hepatitis B core antibodies (anti-HBc) or hepatitis B surface antigen (HBsAg).

Study sites evaluated the presence of 21 potential HBV risk factors during the period 6 weeks to 6 months before symptom onset, as well as 2 lifetime risk factors; people could have more than 1 risk factor.

The researchers then divided up the risk factors and compared 2 mutually exclusive risk categories:

Individuals with both types of risk factors were classified as having healthcare-associated risk, so the study captured cases that likely could potentially have been linked to health procedures or facilities, therefore representing an upper boundary.

Results

	Between 2005 and 2009, a total of 1269 cases of acute hepatitis B were reported by the 5 states.
	Of these, 287 patients, or 22.6%, had no recorded exposure risks and were excluded from the analysis.
	Among the 982 people with available risk information:
	183 (18.6%) had healthcare-associated risk factors; 396 (40.3%) had sex/drug/household exposure risk; 253 (25.8%) had no identified exposure risk factors.
	Patients with healthcare-associated risk factors were significantly older than people with sex/drug/household exposure (median 46 vs 39 years) and more likely to be female (38% vs 23%), but were similar in racial/ethnic distribution.
	Out of 183 healthcare-associated cases, 12 (6.6%) were residents of long-term care facilities such as nursing homes.

Based on these findings, the researchers concluded, "Nearly 1 in 5 acute hepatitis B cases were identified with possible healthcare-associated risk. Almost 7% were in long-term care."

The results "suggest that healthcare-associated risk may represent a measurable portion of acute hepatitis B cases," they added.

Investigator affiliations: Centers for Disease Control and Prevention, Atlanta, GA; Oregon Public Health Div, Portland, OR; Connecticut Dept of Health, Hartford, CT; New York City Dept of Health and Mental Hygiene, New York, NY; Colorado Dept of Public Health & Environment, Denver, CO; Minnesota Dept of Health, St Paul, MN; New York State Dept of Health, Albany, NY.

9/24/10

Reference
D Daniels, M Klevens, K Iqbal, and others. Measuring Healthcare-Associated Hepatitis B Virus Transmission: U.S. 2005-09. 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010). Boston, September 12-15, 2010. (Abstract K-256).