Missed Opportunities (IMAGE) Brown University Caption A transmission electron microscope image shows particles of the hepatitis B virus. A vaccine has existed since 1982 but many people at high risk for getting the virus nevertheless are not inoculated. Credit CDC/ Dr. Erskine Palmer Usage Restrictions Credit required License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.