Background Illness accounts for a significant proportion of consultations with team physicians. Furthermore, intercontinental travel is a risk factor for illness in teams participating in the annual 16-week Super Rugby Tournament.

Objective To determine if the incidence of illness in players participating in the Super Rugby Tournaments changed after illness prevention strategies were recommended before the 2013 tournament.

Design Prospective cohort study.

Setting Super Rugby Tournaments from 2010 to 2015 (6-year period).

Participants Elite rugby players from five South African Super Rugby teams (average squad size=30 players).

Assessment Participating teams and players were followed daily during the ≈16 week competition period for 6 years (96 959 player days). Team physicians recorded daily squad size and completed a daily illness log using an online injury and illness registration system (100% compliance). Following data analysis of the 2010 tournament resulting in two publications in 2012, recommendations to prevent illness were introduced before the 2013 tournament. Furthermore, in 2014, detailed written illness prevention guidelines were distributed to all team physicians.

Main Outcome Measurements Incidence of illness (illness per 1000 player days).

Results The incidence of illness (per 1000 player days; 95% CI) for each year was as follows: 2010 (14.3; 12.2–16.8), 2011 (12.2; 10.3–14.3), 2012 (12.4; 10.6–14.3), 2013 (4.8; 3.8–5.9), 2014 (6.5; 5.3–7.9) and 2015 (6.1; 5.1–7.2). The incidence of all illness in the period 2013 to 2015 was significantly lower in each year compared to the incidence of illness in each year during the period 2010 to 2012.

Conclusions In this 6-year prospective cohort study, there was a significant reduction in the incidence of illness in the years following the publication of illness data in 2012. We suggest that the illness prevention recommendations, introduced from 2013, could account for this reduction in illness incidence.