Epstein-Barr Virus (EBV) DNA as a Potential Marker of in vivo Immunity in Professional Footballers.

Introduction: Team sport athletes have increased susceptibility to upper respiratory symptoms (URS) during periods of intensified training and competition. Reactivation of Epstein-Barr Virus (EBV) may be a novel marker for risk of upper respiratory illness (URI) in professional athletes. Aims: To investigate changes in salivary EBV DNA (in addition to the well-established marker, salivary secretory immunoglobulin A), and incidence of URS in professional footballers. Methods: Over a 16-week period (August to November 2016), 15 male players from a professional English football League 1 club provided weekly unstimulated saliva samples (after a rest day) and recorded URS. Saliva samples were analyzed for secretory IgA (ELISA) and EBV DNA (qPCR). Results: Whole squad median (interquartile range) saliva IgA concentration and secretion rate significantly decreased (p < .05) between weeks 8 and 12 (concentration, 107 (76-150) mg/L healthy baseline to 51 (31-80) mg/L at week 12; secretion rate 51 (30-78) µg/min healthy baseline to 22 (18-43) µg/min at week 12). Two players reported URS episodes during week 10, both after IgA secretion rate decreased below 40% of the individual's healthy baseline. EBV DNA was detected in the weeks before URS but also at other times and in healthy players (overall frequency 40%, range 11-78%) and frequency was similar between the URS and healthy group. Conclusion: These findings confirm salivary IgA as a useful marker of URS risk but EBV DNA was not. Further research capturing a greater number of URS episodes is required, however, to fully determine the utility of this marker.

Coldzyme® Mouth Spray reduces duration of upper respiratory tract infection symptoms in endurance athletes under free living conditions.

Upper respiratory tract infection (URTI) can compromise athlete preparation and performance, so countermeasures are desirable. The aim of this study was to assess the effects of ColdZyme® Mouth Spray (ColdZyme) on self-reported upper respiratory tract infection in competitive endurance athletes under free-living conditions. One hundred and twenty-three endurance-trained, competitive athletes (recruited across 4 sites in England, UK) were randomised to control (no treatment, n = 61) or ColdZyme (n = 62) for a 3-month study period (between December 2017 and March 2018; or December 2018 and April 2019). They recorded daily training and illness symptoms (Jackson common cold questionnaire) during the study period. A total of 130 illness episodes were reported during the study with no difference in incidence between groups (episodes per person: 1.1 ± 0.9 Control, 1.0 ± 0.8 ColdZyme, P = 0.290). Episode duration was significantly shorter in ColdZyme compared to Control: Control 10.4 ± 8.5 days vs. ColdZyme 7.7 ± 4.0 days, P = 0.016). Further analysis to compare episodes with poor vs. good compliance with ColdZyme instructions for use (IFU) within the ColdZyme group showed a greater reduction in duration of URTI when compliance was good (9.3 ± 4.5 days in ColdZyme poor IFU compliance vs. 6.9 ± 3.5 days in ColdZyme good IFU compliance, P = 0.040). ColdZyme may be an effective countermeasure to reduce URTI duration, which was significantly lower (by 26-34%) in the ColdZyme treatment group (with no influence on incidence). This may have implications for athlete performance.