Hepatitis A and B Immunity and Vaccination in Chronic Hepatitis B and C Patients in a Large United States Cohort

Background. Hepatitis A and B vaccines are effective in preventing superinfection and sequelae in patients with chronic hepatitis B or C. We describe immunity and vaccination against hepatitis A and B in chronic hepatitis patients from the US Chronic Hepatitis Cohort Study. Methods. We identified chronic hepatitis B and C patients with healthcare utilization during 2006-2008 and 12 months of enrollment. We used electronic laboratory records to determine immunity and medical and billing records for vaccination history. Immunity against hepatitis A was defined by positive hepatitis A antibody or documented vaccination. Immunity against hepatitis B was defined as hepatitis B surface antibody level >= 10 mIU/mL or core antibody positive, or by documented vaccination. Results. Among 1635 chronic hepatitis B patients, 978 (59.8%) were immune or vaccinated against hepatitis A, 122 (7.5%) had negative hepatitis A antibody tests, and 535 (32.7%) had no testing or vaccination record. Among 5328 chronic hepatitis C patients, 2998 (56.3%) were immune or vaccinated against hepatitis A, 659 (12.4%) had negative hepatitis A antibody tests, and 1671 (31.4%) had no testing or vaccination record. Additionally, 3150 (59.1%) chronic hepatitis C patients were immune or vaccinated against hepatitis B, 1003 (18.8%) had a negative test result, and 1175 (22.1%) were neither tested for nor vaccinated against hepatitis B. Conclusions. Approximately 40% of chronic hepatitis B and C patients are susceptible to or have no documented immunity or vaccination against hepatitis A or hepatitis B. Clinicians should consider antibody testing and vaccination for this vulnerable population.