Posted Oct. 3, 2018. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.
The Spokane Regional Health District (SRHD) is alerting you to an outbreak of acute hepatitis B virus (HBV) infection that is occurring in Spokane County. An increase in the number of cases of acute HBV infection reported to SRHD began with the first onset in mid-June 2018, primarily in persons who use injection drugs and their contacts. Further testing is being done at the Centers for Disease Control & Prevention (CDC) to assist in determining relationships between the several cases that have been identified thus far. Given the impact of the opioid epidemic and continued injection drug use in our community, there is an increased likelihood that additional cases may occur. We are asking healthcare providers to:
Of the several cases that have been identified with onsets since mid-June 2018, most are males. The age range of cases at diagnosis are 27 to 55. Seventy five percent have evidence of injection drug use history; the others report high risk sexual activity only. Most cases reported onset in August, although new cases were recently identified.
The incubation period for HBV infection is 45-180 days (usually 60-90 days). Transmission occurs by contact with the blood, semen or vaginal secretions of an infected person. The virus is introduced through mucous membranes or broken skin. HBV may also be found at low levels in saliva and other body fluids. Infection can occur with minor blood contact, such as within a household, and often a specific exposure event cannot be determined. Persons are contagious for as long as HBsAg, HBV DNA is present in the blood, regardless of symptoms. When symptoms do occur, viremia begins several weeks before onset and lasts several months if the infection resolves (which occurs in 90-95% of adults with acute infection), or indefinitely in chronic infections.
Testing for HBV is available through commercial laboratories. Typical interpretation of test results for HBV virus infection is shown below:
A typical serologic course of acute hepatitis B with recovery or progression to chronic infection is shown in Figures 1 and 2 below. Occasionally, a person will have neither HBsAg nor anti-HBs detectable during late acute illness but may still be infectious for one to two weeks. During this “window phase,” the only positive serological test may be core antibodies (anti-HBc).