Infectious mononucleosis, known as “mono,” is a contagious illness characterized by fatigue, fever, and a sore throat. It is caused by a virus that spreads through bodily fluids, primarily saliva.
The Epstein-Barr Virus and Mononucleosis
The Epstein-Barr virus (EBV) causes infectious mononucleosis. This common virus infects an estimated 9 out of 10 adults globally, often without noticeable symptoms, especially when exposure occurs during childhood. However, initial infection during adolescence or young adulthood is more likely to lead to classic mono symptoms.
Beyond acute mononucleosis, EBV is associated with several serious long-term health conditions. It is linked to certain cancers, including Burkitt lymphoma, Hodgkin lymphoma, and nasopharyngeal carcinoma. Evidence also suggests a connection between EBV infection and autoimmune diseases like multiple sclerosis (MS). These associations underscore the public health motivation for vaccine development.
Current Status of Vaccine Development
As of 2024, no vaccine for infectious mononucleosis or the Epstein-Barr virus is approved for widespread public use. Despite decades of research, an effective vaccine remains a goal. However, active research and clinical trials are underway.
Efforts include those by institutions like the National Institutes of Health (NIH) and companies such as Moderna. Moderna has developed mRNA vaccine candidates, which aim to prevent initial EBV infection by targeting viral glycoproteins involved in cell entry. Other candidates are being developed to prevent longer-term complications associated with EBV, containing additional antigens for broader protection.
Challenges in Creating an EBV Vaccine
Developing an effective vaccine against the Epstein-Barr virus presents biological complexities. EBV is a herpesvirus, able to establish a lifelong, dormant (latent) infection within the body’s B cells. This latency allows the virus to evade the immune system, making it a difficult vaccine target.
The virus expresses different proteins during its active (lytic) and latent phases, complicating vaccine design. Researchers must determine which viral proteins will elicit a robust and long-lasting protective immune response. Additionally, the lack of an animal model that fully mimics human EBV infection and disease progression hinders preclinical testing.
Preventing Mononucleosis Without a Vaccine
Prevention strategies focus on limiting virus transmission. EBV primarily spreads through saliva, so avoiding direct contact with infected bodily fluids is key. This includes refraining from sharing drinks, food, eating utensils, or toothbrushes.
Avoiding kissing someone with an active infection is also recommended. Due to EBV’s widespread nature and the fact that individuals can transmit the virus without showing symptoms, complete avoidance of infection is challenging. Practicing good hygiene and being mindful of close contact can help reduce transmission risk.