A study of the preventive effects of an Echinacea extract upon the occurrence of respiratory infections in healthy students

INTERVENTION: Randomised dose allocation of trial or placebo tablets of same size and shape with their identities concealed from supervisors, investigators and participants until outcome data collected and entered on a spreadsheet. The trial involves 3 academic supervisors, 5 Student Investigators (SIs) and 60 student subjects aged 18‐30 years (12 per SI). Intervention consists of daily oral intakes of either a trial dose of ca. 900 mg dried Echinacea purpurea as powder incorporated in 3 x 294 mg tablets or a control dose consisting of placebo tablets of the same size and shape as the trial dose. Coin‐tossing will be used to randomly allocate codes in pairs to either pre‐filled Echinacea (heads) or placebo (tails) containers, and in their order of recruitment subjects will be allocated to these codes. Dose to be taken with/without food either all together or spread through the day. Dose period: Two consecutive 3‐week periods separated by 1 week off‐dose (i.e., treatment period 7 weeks in total). Subjects: Students aged 18‐30 recruited by personal contact of student investigators. Any person who is on prescribed medication needs to seek medical advice before taking Echinacea. Numbers: This is a pilot study which has a target recruitment of 60 students in total. CONDITION: Upper respiratory tract infections ; Respiratory ; Upper respiratory tract infections PRIMARY OUTCOME: Incidence of illness and number of days of illness in each week ‐ frequency of symptoms of infectious illness related to immunity (e.g., flu, cold, mouth ulcers) measured using appropriate scoring methods, and investigators monitor subjects' compliance and collect information regarding incidence/symptoms of infection weekly by pre‐arranged telephone contact SECONDARY OUTCOME: ; 1. Personal information of volunteer trial subjects (home living arrangements, sleeping habits, medications, supplement usage [including antioxidants], number of URTIs in preceding 12 months, stress, smoking, alcohol intake, exercise frequency), assessed using form completed by volunteer trial subject prior to start of dose‐period (trial intervention); 2. Feelings of illness defined from list of URTI symptoms, recorded using weekly diary forms completed by SI for each of their 12 volunteer trial subjects by recording in daily tick‐boxes (i.e., record of URTI incidence and days ill) weekly throughout the trial intervention; 3. Missed doses, recorded using weekly diary forms completed by SI for each of their 12 volunteer trial subjects by recording in daily tick‐boxes weekly throughout the trial intervention; 4. Ill effects of the dose and where applicable symptoms, recorded using weekly diary forms completed by SI for each of their 12 volunteer trial subjects weekly throughout the trial intervention; 5. Exercise frequency (minimum time‐period per iteration 20 mins), recorded using weekly diary forms completed by SI for each of their 12 volunteer trial subjects by recording in daily tick‐boxes weekly throughout the trial intervention; 6. Doses taken, recorded using form with tick‐boxes for each (dated) day of the trial completed by each of the 12 volunteer trial subjects daily throughout the trial intervention; 7. Dietary intakes, recorded using diet diary of all the food and drink consumed completed by volunteer trial subjects over two 4‐day periods in the 2nd and 7th weeks during the trial intervention; 8. Subjective perceptions of subjects, recorded using follow‐up questionnaire completed by each of the 12 volunteer trial subjects (including dose identity, benefit, side‐effects) following the trial intervention; ; INCLUSION CRITERIA: 1. Age: 18‐30 years 2. Male or female 3. Occupation: student 4. Health status: healthy