Schwellnus, Martin Peter2023-02-132023-02-132023-04-212023*https://repository.up.ac.za/handle/2263/89431Thesis (PhD (Sports Medicine))--University of Pretoria, 2023.INTRODUCTION : An acute respiratory infection (ARinf) is the most common illness affecting athletes and can result in days lost to training/competing i.e. time loss, affecting safe return to sport (RTS). The RTS process is a continuum, consisting of two defined time points: days to return to training (RTT) and days to return to full performance (RTFP). AIM : To formulate scientific and medically based RTS guidelines in athletes with recent ARinf, including COVID-19, based on clinical criteria and laboratory investigations. A secondary aim is to determine the incidence, and risk factors of ARinf, including SARS-CoV-2 in a cohort of athletes. OBJECTIVES : To determine the incidence of SARS-CoV-2 in a cohort of athletes, explore factors associated with prolonged RTT, determine frequency of multi-organ involvement and determine factors associated with prolonged RTFP after SARS-CoV-2 infection in athletes. METHODS: Study designs : Literature reviews: Systematic review with meta-analyses (ARinf) and narrative review (SARS-CoV-2). Original research: Cohort studies with retrospective (online questionnaire) and prospective (clinical assessment and follow-up) components. Study setting : Sport, Exercise Medicine and Lifestyle Institute (SEMLI) clinical services, University of Pretoria, South Africa Participants Athletes with recent ARinf/SARS-CoV-2 infection RESULTS : Main findings from the systematic review and meta-analysis were that 20% of suspected/confirmed ARinf result in time loss, with a mean symptom duration of 7 days. The narrative review highlighted the lack of scientific RTS guidelines after SARS-CoV-2 infection in athletes. Main findings from the original research were: 1) the incidence of ARinf (0.31) and SARS-CoV-2 (0.23) per 1000 player days was higher during contact vs. non-contact phases (p<0.01) and no factors were associated with the incidence of ARinf/SARS-CoV-2; 2) days to RTT and factors associated with prolonged (RTT) in athletes with recent SARS-CoV-2 infection were (univariate model): female (p=0.01), reduced training in the seven days pre-infection (p=0.003), presence of symptoms in “chest and neck” (p=0.004) and “whole body” (p=0.025) regions and multiple models showed greater number of symptoms in each anatomical region and total number of symptoms were significantly associated with prolonged RTT; 3) evidence of multi-organ involvement (10-28 days since onset of SARS-CoV-2) was found in 93-100% of athletes, consisting of residual symptoms (87%), abnormal clinical signs (46%) or abnormal laboratory investigations (60-75%), and total number of acute symptoms was a measure of disease severity, with >5 symptoms associated with higher risk for multi-organ involvement; and 4) days to RTFP (median;IQR) in symptomatic athletes was twice as long (64;42-91) than in asymptomatic athletes (30;23-40) (p=0.026). Factors associated with prolonged RTFP (univariate model) were: females (p=0.014), endurance athletes (p<0.0001), number of co-morbidities (p=0.001) and history of respiratory disease (p=0.026), and in multiple models, an increase in the number of total symptoms and symptoms in each anatomical region, remained significantly associated with RTFP. CONCLUSION : Symptoms (type and number) during the acute phase of SARS-CoV-2 infection, may indicate severity of infection (multiple organ involvement), and predict duration for RTT and RTFP - thus forming the basis of practical and scientific RTS guidelines. Future research should determine if acute phase symptoms are associated with RTS outcomes in other ARinf.en© 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.UCTDAthletesAcute respiratory infectionReturn to sportsSARS-CoV-2 infectionThesis98012232