Human respiratory syncytial virus (IMAGE) Johns Hopkins Medicine Caption Scanning electron micrograph of human respiratory syncytial virus (RSV) virions (colorized blue) and tagged with antibodies (colorized yellow) against the virus’ fusion protein — the target of RSV vaccines. Credit National Institute of Allergy and Infectious Diseases, National Institutes of Health Usage Restrictions No restrictions. License Public Domain 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.