As of 2024 ^[update] , a vaccine against Epstein?Barr virus was not yet available. ^{[1] [2]} The virus establishes latent infection and causes infectious mononucleosis . There is also increasingly more evidence that EBV may be a trigger of multiple sclerosis . ^[3] It is a dual- tropic virus, meaning that it infects two different host cell types ? in this case, both B cells and epithelial cells . One challenge is that the Epstein?Barr virus expresses very different proteins during its lytic and its latent phases . Antiviral agents act by inhibiting viral DNA replication, but as of 2016 ^[update] , there was little evidence that they are effective against Epstein?Barr virus, they are expensive, they risk causing resistance to antiviral agents, and (in 1% to 10% of cases) can cause unpleasant side effects . ^[1]

Several clinical trials for a vaccine were conducted in 2006?2008. ^{[4] [5] [6]} The viral proteins Gp350/220 are a primary target, ^[7] but this would only block infection of B cells, not epithelial cells. A vaccine called MVA-EL has been also proposed as a target for EBV-positive cancers, but this would only be effective in combating EBV-related cancers, not the EBV infection itself. ^[8] VLP ( virus-like particle )-based EBV vaccines are also the subject of intensive research. ^[9]

In April 2018, the first human antibody that blocks Epstein-Barr Virus was discovered, called AMMO1. ^[10] It blocks glycoproteins gH and gL. This discovery defines new sites of vulnerability on Epstein-Barr Virus, and neutralizes the dual-tropic infection (stopping both infection of B cells and epithelial cells). It is the most promising discovery to date, as it is the first that may be able to block both B cell infection and epithelial infection. ^[11]

In 2021, Moderna announced two mRNA vaccine candidates targeting EBV: a prophylactic mRNA-1189 and a therapeutic mRNA-1195. ^[12] Regarding the mRNA-1189, the company said that the "vaccine encodes five glycoproteins to inhibit both mechanisms for viral entry into B cells (gp350 plus gH/gL/gp42), adds protection for epithelial cells (gH/gL), and includes gB for protection of all cells." ^[13] The viral proteins produced by the mRNA in this vaccine are expressed in their native form, bound to the cell membrane , where they are available for recognition by the immune system . ^[12] The company began Phase I clinical trials of mRNA-1189 on 5 January 2022. ^[14] The other candidate, mRNA-1195 vaccine, is being developed to prevent longer-term complications which may be caused by EBV, and it contains additional antigens compared to mRNA-1189. ^[12] In early 2023, Moderna began Phase I clinical trials of mRNA-1195. ^{[ citation needed ]}

References [ edit ]

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