Hepatitis A virus (HAV) and hepatitis B virus (HBV) can have fatal consequences for people who already have chronic liver disease, yet widely available vaccines against these viruses are not being used nearly as often as they should, according to a report in the October 2011 issue of Hepatology. In fact, people living with HCV—along with those living with diabetes, another high-risk group—were no more likely to have been vaccinated than members of the general U.S. population.

Though vaccination rates in the United States have increased in recent years—HAV by 70 percent and HBV by 40 percent—they remain low: 60 percent of adults remain vulnerable to HAV infection and only 20 percent have been vaccinated against hepatitis B.

Vaccination against HAV and/or HBV is especially important for people with chronic liver disease, including those living with HCV or HBV. Hepatitis A and hepatitis B can cause serious, rapidly progressive illness leading to liver failure and death in people with underlying liver disease. People with diabetes were included in this study as a high-risk group because non-alcoholic fatty liver disease (NAFLD) is common among diabetics, and diabetes itself increases the risk for liver damage.  

Zobair Younossi, MD, MPH, and Maria Stepanova, PhD, researchers from the Center for Liver Diseases and Department of Medicine at Inova Fairfax Hospital, and the Betty and Guy Beatty Center for Integrated Research in Falls Church, Virginia, used data collected in the National Health and Nutrition Examination Survey (NHANES) from 1999 until 2008. They looked at rates of chronic liver disease and diabetes, among almost 25,000 NHANES participants. Overall, 14 percent of the group had chronic liver disease—such as hepatitis B, hepatitis C, alcohol-related liver disease, iron overload and NAFLD—and 8.6 percent had diabetes.

The researchers also looked at vaccination rates, and immunity to, HAV and HBV. During the period between 2005 and 2008, a mere 20 percent of people with chronic liver disease were vaccinated against HAV. Hepatitis B vaccination was reported by only 32 percent of people with chronic liver disease. Both HAV and HBV vaccination rates among the general public were similar. However, people with diabetes were far less likely to have been vaccinated against hepatitis A (15 percent) or hepatitis B (22 percent).

Vaccination was considered effective when people who reported receiving at least one dose of HAV or HBV vaccine also had evidence of immunity to HAV or HBV.  Shockingly, the researchers found that vaccination against HAV and HBV was ineffective for 50 percent of both high-risk groups as well as the general population. The authors attributed this to incomplete vaccination, since many people did not receive the entire series of injections required for full immunity (two injections for HAV and three injections for HBV). In addition, both vaccines were less effective for obese people, and HBV vaccination was less effective for people over 65 years of age, and people with diabetes.
“Given the epidemic of obesity and diabetes, these findings, though preliminary, pose special interest and should be considered by vaccination manufacturers, healthcare providers, public health leaders, and health policy makers,” the authors wrote.

Although several sets of guidelines provide recommendations for HAV and HBV vaccination for high-risk groups, the authors noted that they are inconsistent and not widely implemented, and suggested that harmonization and implementation of these guidelines is urgent.

The authors strongly recommend prioritizing HAV and HBV vaccination in the United States, where obesity and diabetes are widespread among an aging population. “This situation requires immediate attention, given the public health implication of acute viral hepatitis in older patients, those with CLD as well as patients with obesity- and diabetes-related NAFLD,” they conclude.