A study of more than 2,000 entrants to Edinburgh University has established that Epstein-Barr virus (EBV) is sexually transmitted. Individuals who were sexually active before arrival at university, particularly if they had had numerous sex partners, were more likely to have contracted the virus. The risk of EBV was lower among students who always used a condom than among those who had unprotected sexual intercourse. The research is published in the February 15th edition of the Journal of Infectious Diseases.
EBV is a human herpes virus that causes, and is associated with, a variety of human tumours, the most notable being non-Hodgkin’s lymphoma, an AIDS-defining cancer. Primary infection is often seen in post-pubescent individuals and is characterised by fever, sore throat, leg and muscle soreness and fatigue. Previous investigation has shown that EBV is produced in the saliva of persistently infected individuals, and that transmission almost certainly occurs orally, through close salivary contact during kissing. The virus has also previously been reported in both male and female genital secretions, suggesting that further study could determine a risk of sexual transmission.
A total of 2,006 students with an average age of 18 years were recruited into the study, of whom 1,496 (75%) tested positive for EBV-specific antibodies.
Questionnaires and serum samples were used to identify sexual and nonsexual risk factors for EBV seroconversion overall and, for the first time, separately by EBV type (type 1 or type 2).
Seropositivity was significantly higher among female (79%) than among male (68%) students, among those who were 19 years and older and for those who had lived in a tropical country.
Sexual activity before coming to the university was significantly associated with increased risk of EBV (p
In addition, separate analysis of men and women revealed that condom use only significantly reduced the risk of EBV infection in men (p
Prevalence of EBV was lower amongst gay students.
The investigators also conducted analysis to see if there was any difference in the risk factors for infection with EBV type 1, EBV type 2, and dual EBV infection. Infection with type 1 was associated with sexual activity before university (p
Type 2 infection was also associated with sexual activity, but was as likely to be present in gay students as their heterosexual peers. Condom use did not significantly reduce the risk of type 2 infection.
There were only a small number of dual infections available for analysis. However, it appeared that the risks were similar to type 1, and neither condom use nor sexuality were protective.
“The present study provides further evidence that EBV may be sexually transmitted and new evidence that the risk factors for type 1 and type 2 EBV infection may differ”, conclude the investigators.
An accompanying editorial notes that of the eight human herpes viruses, four - HSV, CMV, KSHV, and EBV – are now known to be sexually transmitted. However, the authors doubt EBV will be “given much priority in STD clinics anytime soon” despite its “still-unfolding virological, oncological, and sociological fascinations.”
Higgins CD et al. A study of risk factors for acquisition of Epstein-Barr virus and its subtypes. J Infect Dis 195: 474 – 482, 2007.
Pagano JS. Is Epstein-Barr virus transmitted sexually? J Infect Dis 195: 469 – 470, 2007.