Acute sore throat. The following symptoms were recorded daily: feeling of fever, headache, general discomfort or malaise, cough, sore throat, difficulty swallowing (solids or liquids), runny nose, ear pain, diarrhoea, nausea, vomiting, difficulty sleeping and difficulty in carrying out daily life activities. Each symptom was scored following a 0–6 scale.

Rhinosinusitis. The following symptoms were recorded daily: feeling of fever, general discomfort or malaise, headache, sudden pain in the face, pain in the face on touching, runny nose, nasal mucus colour, cough, sore throat, expectoration or phlegm (mucus when coughing), diarrhoea, nausea, vomiting, difficulty sleeping and difficulty in carrying out daily life activities. Each symptom (save for nasal mucus colour) was scored from 0 to 6. In the case of the presence of nasal mucus colour, the colour was assessed: transparent (T), light yellow clear (Y), green (V) or other (O).

Acute bronchitis. The following symptoms were recorded daily: feeling of fever, general discomfort or malaise, cough, expectoration or phlegm (mucus when coughing), shortness of breath (suffocation, fatigue), pain when breathing (chest pain), chest breathing sounds, diarrhoea, nausea, vomiting, difficulty sleeping and difficulty in carrying out daily life activities. Each symptom (save for expectoration or phlegm) was scored from 0 to 6. In the case of expectoration or phlegm, the colour was assessed: transparent (T), light yellow clear (Y), green (V) or other (O).

Influenza. The following symptoms were recorded daily: feeling of fever, runny nose, headache, general discomfort or malaise, cough, muscle pain, sore throat, sweat or chills, shortness of breath, weakness or fatigue, dizziness, diarrhoea, nausea or vomiting, difficulty sleeping and difficulty in carrying out daily life activities. Each symptom was scored from 0 to 6.