title: A cohort study among university students: identification of risk factors for Epstein-Barr virus seroconversion and infectious mononucleosis.
abstract: BACKGROUND
  A vaccine against Epstein-Barr virus (EBV) infection is in clinical trials. Up-to-date information on risk factors for EBV infection and infectious mononucleosis (IM) among young adults is required to inform a vaccination strategy.
  
  
  METHODS
  We carried out a prospective study on a cohort of university students. All EBV-seronegative students were asked to report symptoms of IM and were followed up 3 years later to undergo repeat EBV testing and to complete a lifestyle questionnaire. EBV typing was performed for these subjects, as well as for students who were EBV seropositive at enrollment and for additional students with IM.
  
  
  RESULTS
  A total of 510 students (25%) who took part in the study were EBV seronegative when they entered the university; of the 241 who donated a second blood sample 3 years later, 110 (46%) had seroconverted to EBV, 27 (25%) of whom developed IM [corrected] Penetrative sexual intercourse was a risk factor for EBV seroconversion (P = .004), but neither condom use nor oral sex significantly altered the rate of seroconversion. EBV type 1 was significantly overrepresented in IM, compared with silent seroconversion (P = .001).
  
  
  CONCLUSIONS
  Our findings suggest that acquisition of EBV is enhanced by penetrative sexual intercourse, although transmission could occur through related sexual behaviors, such as "deep kissing." We also found that EBV type 1 infection is significantly more likely to result in IM. Overall, the results suggest that a large EBV type 1 load acquired during sexual intercourse can rapidly colonize the B cell population and induce the exaggerated T cell response that causes IM. Thus, IM could, perhaps, be prevented with a vaccine that reduces the viral load without necessarily inducing sterile immunity.
authors.affiliation: Clinical and Molecular Virology Laboratory, School of Biomedical Sciences, University of Edinburgh, Summerhall, Edinburgh, EH9 1QH, United Kingdom. D.Crawford@ed.ac.uk
authors.forename: Dorothy H
authors.initials: DH
authors.lastname: Crawford
authors.forename: Karen F
authors.initials: KF
authors.lastname: Macsween
authors.forename: Craig D
authors.initials: CD
authors.lastname: Higgins
authors.forename: Ranjit
authors.initials: R
authors.lastname: Thomas
authors.forename: Karen
authors.initials: K
authors.lastname: McAulay
authors.forename: Hilary
authors.initials: H
authors.lastname: Williams
authors.forename: Nadine
authors.initials: N
authors.lastname: Harrison
authors.forename: Stuart
authors.initials: S
authors.lastname: Reid
authors.forename: Margaret
authors.initials: M
authors.lastname: Conacher
authors.forename: Jill
authors.initials: J
authors.lastname: Douglas
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Swerdlow
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007244:Infectious Mononucleosis / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012698:Serologic Tests; D013334:Students; D014495:Universities