Screening for Epstein-Barr virus (EBV) infection status in university freshmen: acceptability of a gingival swab method

Abstract

Prophylactic vaccines against Epstein-Barr virus (EBV) are under development. EBV-naïve college freshmen are ideal candidates for an efficacy trial, because their incidence of infectious mononucleosis (mono) during freshman year is as high as 20%. To assess perceptions about mono and a mono vaccine, and to learn if EBV immune status could be determined using a gingival swab rather than phlebotomy, we performed a cross-sectional study of 235 healthy students at the beginning of their freshman year. Subjects completed questionnaires and donated oral washes, gingival swabs and venous blood. Overall, 90% of students found the swab easy to use and 80% preferred the swab over venepuncture. Of the 193 students with sufficient samples, 108 (56%) had EBV antibodies in blood vs. 87 (45.1%) in the gingival swab. The sensitivity and specificity of the swab compared with blood for detecting EBV antibodies was 75.9% and 94.1%, respectively, with an accuracy of 89.3%. EBV DNA was detected in the oral wash and swab of 39.2% and 30.4% of blood-antibody-positive individuals, respectively. In conclusion, 44% of our freshmen were EBV-naïve and thus vaccine candidates, the gingival swab was an acceptable alternative to phlebotomy for detecting EBV antibody but needs improved sensitivity, and the perceived value of EBV vaccine was high (72% believed they would benefit).

Keywords: EBV antibodies; EBV infection status; EBV shedding; EBV vaccine; Epstein–Barr virus (EBV); gingival swab; oral wash.

Fig. 1.

Enrolment summary and corresponding EBV antibody prevalence. Antibody prevalence was determined using the gold standard method of blood plasma, unless noted. (+)* = EBV VCA IgG antibody-positive; (−)* = EBV VCA IgG antibody negative; *cut-off values previously described.

Fig. 2.

GCF vs. blood plasma EBV VCA IgG EIA antibody units. Cut-off by the manufacturer's instructions.

Fig. 3.

ROC curve of GCF EBV VCA IgG antibody. AUC = 0.91 (0.86, 0.95), P < 0.0001.

Fig. 4.

ROC curve of EBV VCA IgG antibody in GCF by volume of GCF collected. 0.05–0.1 mL AUC = 0.86 (0.78, 0.94), 0.2–0.3 mL AUC = 0.94 (0.89, 0.99), ⩾0.4 mL AUC = 0.90 (0.80, 0.99).

Fig. 5.

Attitudes regarding the gingival swab and the value of an EBV vaccine. Students were asked to answer based on their agreement to each of the questions stated above.