In response to recent outbreaks of hepatitis A virus (HAV), health experts are urging people with hepatitis B and C viruses (HBV, HCV) to get vaccinated against hep A.

“Hepatitis A is a highly contagious liver infection,” says Noele Nelson, MD, PhD, MPH, a medical officer in the Division of Viral Hepatitis at the Centers for Disease Control and Prevention. “It can range from a mild illness lasting a few weeks to a severe illness lasting several months. When this disease affects populations with already poor health, such as those with hepatitis B and C infections and chronic liver disease, infection can lead to serious outcomes, including death. Vaccination is the most important tool we have to prevent hepatitis A and stop outbreaks.”

Nelson and her colleagues reviewed data from a large cohort study of people with hep B or C. Of the individuals included in this data set, 33 percent of those with HBV and 34 percent of those with HCV had never been tested for HAV. As for those who had been tested for hep A, a respective 59 percent and 39 percent of those with hep B and C had hep A antibodies. Of those who tested negative for hep A antibodies, a respective 60 percent and 62 percent of those with hep B and C never got a follow-up hep A vaccination.