Most adults in the United States are not immune to hepatitis A or hepatitis B, a new study indicates.
Scientists based in Minnesota analyzed years of data from a national survey and found that a minority of those with results from hepatitis A and hepatitis B testing showed immunity to the diseases.
Hepatitis B vaccination at birth has been recommended since 1991, and for adults without childhood vaccination in recent years. Hepatitis A vaccination was recommended in the 1990s for certain groups, a recommendation later expanded to nearly all children.
“This study found that viral hepatitis protection among U.S. adults was suboptimal, suggesting that targeted, systematic vaccination strategies for hepatitis A and B is warranted,” Dr. Giovanni Roldan, with the University of Minnesota, and co-authors said in the paper, which was published by the Journal of the American Medical Association on Aug. 17.
The researchers took data from the National Health and Nutrition Examination Survey, which the Centers for Disease Control and Prevention says is the only national health survey that includes laboratory tests for participants of all ages.
There were hepatitis test results for 13,514 adults available for analysis. The researchers said the population represents some 226.1 million U.S. adults.
Just 39.5 percent of the adults had immunity to hepatitis A, representing 89.4 million adults. Only 27.1 percent, including 25.2 percent from vaccination, had immunity to hepatitis B.
People were more likely to be immune to hepatitis A if they were younger or born outside of the United States, among other factors. Hepatitis B immunity was linked to younger age.
Limitations of the study included the survey excluding groups at high risk for viral hepatitis, such as people in prisons.
One author reported funding from Miromatrix, which is developing a therapy for liver issues.
Hepatitis A is inflammation of the liver caused by eating contaminated food, drinking contaminated water, or coming into contact with an infected person. Most people recover from hepatitis A with lifelong immunity, according to the World Health Organization, although a small proportion of those infected can suffer severe issues that sometimes lead to death.
Hepatitis B is a liver infection caused by coming into contact with bodily fluids from infected people. Hepatitis B can be acute, which can resolve fully, or chronic, which typically afflicts for life.
The study came after the CDC stopped recommending hepatitis B vaccination for newborns whose mothers tested negative for the disease, due to concerns about whether the benefits of the vaccine outweighed the risks. The CDC in January also narrowed recommendations for hepatitis A vaccination to select children.
