Issue link: https://viewer.e-digitaledition.com/i/1496490
WHAT THE RESEARCH SHOWS Scient i st s have lon g su spec t ed t hat EBV was connected to MS, but since an over whelming 95% of the population contracts EBV by young adulthood and only a handful develop MS, it hasn't been feasible to conduct a randomized trial. For this study, researchers partnered with the U.S. Armed Forces to study serum collected over 20 years from over 10 million young servicepeople, 955 of whom developed MS while in service. (Enlistees are screened for HIV every two years, and the samples are archived.) The researchers compared three serum samples from 801 people who developed MS and matched each to two randomly selected personnel who did not develop MS but were the same age, sex and race or ethnicity. The pairings also considered the branch of military service, dates when the blood was collected, and whether the members were on active duty. The samples were also screened for evidence of cytomegalovirus (CMV), another herpes virus primarily transmitted through saliva. Results showed that after EBV infec- tion, risk of developing MS was 32 times greater, but there was no increase after CMV. Additionally, only EBV seroconver- sion increased neurofilament light chain serum levels, a biomarker of neuroaxo- nal degeneration. "Collectively, these findings strongly su g gest t hat t he occu r rence of EBV i n fect ion , detect able by t he el icited immune response, is a cause and not a consequence of MS," the study concludes. THE FUTURE OF TREATMENT Already, anti-CD20 monoclonal antibodies are one of the most potent treatments for MS. The antibodies deplete the primary site of the latent EBV virus, circulating memory B cells. "There may be therapeutic approaches to block the virus from spreading once there's an infection," says Mark Allegretta, PhD, Vice President of Research, National Multiple Sclerosis Society. "If you look at models such as hepatitis C, there have been drugs that have been developed to prevent the spread of hepatitis C in an individual, and those are very effective. But the challenge for Epstein-Barr virus is that it does establish a latent infection. So it has a latent phase and a lytic phase, and it's very active in the lytic phase, but essentially in the latent phase, it's working to hide itself from the immune system. So designing an approach where a drug would block viral replication may be challenging in this case." COULD AN EBV VACCINE PREVENT MS? Moderna has a lready started a clinica l tr ia l for a vacci ne to protect a ga i nst i n fectious mononucleosis (a nd t hus, EBV ). O t her tr ia ls a re li kely com ing soon. Moderna's tria l is in phase 1 and is current ly enrol ling people a ges 18 to 30. Because so many people develop EBV as children, the ultimate hope is for a vaccine delivered in early childhood. However, whether a vaccine given that young will ultimately prevent MS is yet to be determined. " The mR NA technolog y a llows the development of vaccines very quickly now," says study lead author Alberto Ascherio, MD, DrPH, Professor of Epidemiology and Nutrition, Harvard T.H. Chan School of Public Health. "But like the HPV vaccine … it will take several years to demonstrate that the vaccine does reduce the risk of MS." Another hope is that a vaccine could prevent MS from developing in people who have latent EBV, working in a simi- lar manner as a shingles vaccine, which streng thens the immune response to prevent reactivation. Todd finds reason for optimism in all these possibilities, especia lly when he thinks about his three-year-old child. While MS is not an inherited disease, it can have a genetic risk. "I would certainly be comfortable with my daughter participating in a clinical trial [for the EBV vaccine]," Todd says. "I'm optimistic about the stuff coming down the pipeline, but meanwhile I'm just trying to just focus on the here and now, and what's actually available to me." n Epstein-Barr Virus One of the most common viruses in the world, human herpesvirus 4, a.k.a. Epstein-Barr virus (EBV), remains latent in the body after infection. It is usually spread through saliva from kissing or sharing food or drinks. People can spread the virus for weeks before developing symptoms, which are usually mild but can develop into infectious mononucleosis. M D N E W S . C O M /// M D N E W S S O u T H C E N T R A l P E N N S y lvA N i A ■ 2 0 2 3 1 5