This is a comparative vaccination study of the reactogenicity and immunogenicity of a thiomersal-free formulation of Influsplit SSW® 2002/2003 versus the standard formulation of Influsplit SSW® 2002/2003 in individuals over 18 years.

Inclusion Criteria:

• Healthy subjects who are capable of being vaccinated and subjects with primary diseases (cardiovascular conditions, metabolic conditions such as diabetes mellitus, respiratory diseases) who are capable of being vaccinated and aged over 18 years who want to be vaccinated against influenza or for whom the doctor considers prophylactic influenza immunisation to be indicated.
• The inclusion of individuals who had not been immunised in the 2001/2002 season is preferred.
• Written consent to vaccination must be available after the subjects have been briefed on the study in understandable language.

Exclusion Criteria:

• Use of study or unlicensed medication or administration of a vaccine other than the study vaccine within 30 days preceding vaccination and/or during the study period
• Acute disease at the beginning of the study
• Acute clinically significant changes in the lungs, cardiovascular system, liver or kidney function, identified by physical examination or laboratory tests
• Pregnancy
• Women who would like to fall pregnant during the period from the day of vaccination to 1 month thereafter
• Known allergic reactions that might have been caused by one or more ingredients of the vaccine