During the 18-month observation period, the proportion of symptomatic EBV infections was reduced from 10 percent (nine out of 91) in the control group to 2 percent (two out of 90) in the vaccinated group, indicating that those who did not receive the vaccine were almost 5 times more likely to develop infectious mononucleosis.

With these promising results in a small group of subjects, Dr. Sokal suggested the next step should be “large-scale studies on the benefit in healthy subjects and ability to prevent acute EBV infection and post-transplant lymphoproliferative diseases in transplant patients.” He added, “There is currently no possibility to prevent or to treat acute mononucleosis, which has remained so far an unmet medical problem. This vaccine may decrease the socio-economic impact of acute mononucleosis.”

Development of an EBV vaccine has had a slow and problematic history. These results suggest that the prevention of infectious mononucleosis is possible, and provide a framework for future trials looking to prevent more serious consequences of EBV infection.

In an accompanying editorial, Henry H. Balfour, Jr., MD, of the University of Minnesota Medical School, noted the importance of such studies on EBV vaccines, especially because “the worldwide disease burden due to EBV is enormous.” Balfour agreed that these findings should stimulate future research and larger clinical trials on the prevention and treatment of diseases associated with EBV.

The study was sponsored by Belgian pharmaceutical company Henogen S.A. Authors include employees of Henogen and GlaxoSmithKline Biologicals. Full disclosures are included in the manuscript.

Founded in 1904, The Journal of Infectious Diseases is the premier publication in the Western Hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune mechanisms. Articles in JID include research results from microbiology, immunology, epidemiology, and related disciplines. JID is published under the auspices of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing more than 8,000 physicians and scientists who specialize in infectious diseases. For more information, visit www.idsociety.org.

Fast Facts

1. Epstein-Barr virus (EBV) is one of the most common viruses in humans. Nearly all adults in developed countries such as the United States having been infected, and 30 to 40 percent of adolescences who contract the virus develop infectious mononucleosis.
2. This study showed the efficacy of a vaccine for infectious mononucleosis, reducing the proportion of symptomatic EBV infections from 10 percent in the control group to 2 percent in the vaccinated group.
3. An effective vaccine against mononucleosis is a promising step toward the prevention and treatment of more serious diseases associated with EBV, such as lymphoproliferative diseases or lymphomas.