Influenza (flu) is caused by a virus (a germ) and is spread by contact with nasal (nose) and oral (mouth) secretions. Symptoms include sudden fever, headache, chills, muscle aches, and cough. The main strategy of prevention and control of flu is vaccination. The virus that causes flu usually changes a little bit each year. Therefore, the flu vaccine might change from year to year.
In this study, the vaccine is made with a new technology using tobacco plants (not the same as cigarettes are made from, but from the same family). This species of plant has been used because much is known about this family of plants.