ABSTRACT
OBJECTIVES: To analyse the general and primary outcome-related characteristics of clinical trials protocols on COVID-19 vaccines. STUDY DESIGN AND SETTING: A meta-research study. A search for clinical trial protocols on COVID-19 vaccines was conducted on the ClinicalTrials.gov platform. We considered all protocols of comparative trials registered up to October 26, 2021. RESULTS: Two hundred and eighty-two trials were analysed. The median expected trial duration was 445 days (interquartile range [IQR] = 225), and the median target sample size was 420 participants (IQR = 1638). A retrospective registry (after the start date) was observed for 42.55% of the trials. Randomization procedures were planned by 84.75% and full-blinding procedures by 34.75% of the 282 trials. Most trials were labelled as active or still recruiting, and 14 trials (5%) were completed. None of the 14 trials labelled as completed on our search date had results available. Industry funding was reported by 198 trials (70.2%). Most studies declared more than one primary outcome, usually a safety or immunogenicity outcome, and 59 studies (20.9%) had at least one primary efficacy outcome. The description of the primary efficacy outcomes was limited in most cases, referred to as a non-specified 'efficacy' outcome (18.6%) or described as 'COVID-19 cases' (32.2%). CONCLUSION: the primary outcomes of clinical trials on COVID-19 vaccines are poorly described, and the registers provide insufficient information about them. The registry was retrospectively fulfilled for many trials, which may lead to bias and research waste. Outcomes were generically described and did not provide transparent information for replication in practice, further trials or meta-analyses.
ABSTRACT
Strenuous exercise induces upper respiratory tract infection (URTI), whereas moderate exercise prevents URTI. This study aimed to assess the incidence of URTI and the association between URTI episodes and exercise duration in Japanese collegiate athletes. A cross-sectional survey was conducted with 1,740 participants; 1,235 responses were eligible for analysis. Participants were classified into three groups: control group (weekly total exercise duration <60 min, n=405), exercise group (weekly total exercise duration >60 min, n=193), and athlete group (joined a sports club and weekly exercise frequency >5 days, n=637). We requested the following information from participants: basic characteristics, incidence of URTI symptoms (fever, runny or plugged nose, sore throat, and cough) or influenza for each month over the past year, day of the week exercise is typically performed, and duration of exercise per week. The incidence of URTI episodes per year was significantly lower in the athlete group (2.0 ± 2.4 episodes) compared to the control group (2.6 ± 2.4 episodes, p<0.001). The incidence of URTI episodes did not significantly differ between the control group and exercise group (2.9 ± 2.9 episodes, p=0.607). Although the frequency of URTI episodes and exercise duration were not significantly associated among male athletes (p=0.209), they were positively associated in female athletes (p=0.027). These results indicate that Japanese collegiate athletes experience fewer URTI episodes than non-athletes, but athletes who exercise for long durations may frequently experience URTI, particularly female athletes.
