Days until return-to-play differ for sub-categories of acute respiratory tract illness in Super Rugby players: A cross-sectional study over 5 seasons (102,738 player-days)

Objectives: To document incidence rate and severity of specific sub-categories of respiratory tract illness (RTill) in rugby players during the Super Rugby tournament.

Design: Cross-sectional study.

Methods: Team physicians completed daily illness logs in 537 professional male rugby players from South African teams participating in the Super Rugby Union tournaments (2013-2017) (1141 player-seasons, 102,738 player-days). The incidence rate (IR: illness episodes/1000 player-days) and severity [%RTill resulting in time-loss, illness burden (IB: days lost to illness/1000 player-days) and days until return-to-play (DRTP)/single illness (mean: 95% Confidence Intervals)] are reported for the following specific sub-categories of RTill: non-infective respiratory tract illness (RTnon-inf), respiratory tract infections (RTinf), influenza-like illness, infective sinusitis, upper respiratory tract infections (URTinf), lower respiratory tract infections (LRTinf).

Results: The overall IR of RTill was 2.9 (2.6-3.3). IR was higher for RTinf (2.5; 2.2-2.9) vs. RTnon-inf (0.4; 0.3-0.6) (p < 0.001). For sub-categories the highest IR was in URTinf (1.9; 1.7-2.2), while the % illness causing time-loss was influenza-like illness (100%), LRTinf (91.7%), infective sinusitis (55.6%), and URTinf (49.0%). IB was highest for URTinf (2.0; 1.6-2.5), and the DRTP/single illness was highest for LRTinf (3.2; 2.3-4.4), and influenza-like illness (2.1; 1.6-2.8).

Conclusions: RTinf accounted for >57% of all illness during the Super Rugby tournament, and mostly URTinf. Influenza-like illness. LRTinf caused time-loss in >90% cases. URTinf, LRTinf and influenza-like illness resulted in the highest burden of illness and LRTinf caused the highest DRTP. Prevention strategies should focus on mitigating the risk of RTinf, specifically URTinf, LRTinf and influenza-like illness.