Increased Incidence of Acute Hepatitis B in a Rural County — Alabama, 2012–2015

BACKGROUND:  Alabama acute hepatitis B virus (HBV) infection rates have fluctuated between 1.4 and 2.8 cases/100,000 persons since 1996, despite implementation of national elimination strategies. Through routine surveillance, a rural Alabama county (County X) was identified with a higher rate of acute HBV infection compared with other counties. We conducted an investigation to characterize exposures among County X cases.

METHODS:  Using data reported to Alabama’s National Electronic Disease Surveillance System (NEDSS) from 2012-2015 and population census data, we compared the average 4-year hepatitis B incidence rate in County X with the overall state rate and a demographically similar control county in Alabama. We estimated the prevalence of risk factors, including sexual activity, illicit drug use, exposure to blood, and drug-related arrests among reported cases, from NEDSS and other data sources.

RESULTS:  From 2012-2015, the average 4-year incidence rate in County X of 58.2 cases/100,000 persons was significantly higher than Alabama’s rate of 8.0 cases/100,000 persons (risk ratio [RR]: 7.3; 95% confidence interval [CI]: 5.2–10.1), and the control county’s rate of 24.4 cases/100,000 persons (RR: 2.4; CI: 1.4-4.1). Most frequently reported risk factors in County X included any illicit drug use (26.3%), injection drug use (21.1%), and receiving a tattoo (21.1%). The drug-related arrest rate was significantly higher in County X compared with the state (RR: 1.4; CI 1.2-1.6) and control county (RR: 2.9; CI: 2.2-3.9).

CONCLUSIONS:  Although incidence rates of HBV infection in County X were significantly higher than the state as a whole, a well-defined cause was not evident. Based on risk factors reported, illicit drug use presents an area of concern; further efforts to understand these behaviors in County X are warranted.