Local and state health officials are investigating what they describe as an outbreak of hepatitis A among Allegheny County residents.Eight cases have been reported in the past month, all in the southwest part of the county, according to an advisory issued to health care providers by the Pennsylvania Department of Health."All of last month's eight cases were apparently acquired locally or regionally. Most did not have risk factors associated with the recent national outbreak," the advisory said.What to know about hepatitis A: Watch the video above for more informationBoth the state and county health departments are investigating the outbreak, according to the state's advisory, which was shared on social media by the county Wednesday.Overall, the state says it is seeing an increase in hepatitis A this year."To date, 81 hepatitis A cases have been reported statewide, which is an 80 percent increase compared to the average number of cases reported from the same time period in the previous five years," the Health Department's advisory said. "Concurrently, multiple U.S. states have been experiencing large, ongoing hepatitis A outbreaks affecting people who use drugs and/or people who are homeless, including neighboring states such as Ohio and West Virginia."VACCINATIONS RECOMMENDED FOR THOSE AT RISKThe U.S. Centers for Disease Control and Prevention recommends that any child at least 1 year old should be vaccinated against hepatitis A.Vaccination is also recommended for people who the CDC says are "at increased risk for infection," including:Persons traveling to or working in countries that have high or intermediate endemicity of hepatitis AMen who have sex with menPersons who use injection and non-injection drugsPersons who have occupational risk for infectionPersons who have chronic liver diseasePersons who have clotting factor disordersHousehold members and other close personal contacts or adopted children newly arriving from countries with high or intermediate hepatitis A endemicityPersons with direct contact with persons who have hepatitis AThe CDC also recommends vaccination for people with chronic liver diseases, as they are at increased risk for complications from hepatitis A.