This research during the last decade has focused on the kinetics of the systemic and local immune response to parenteral influenza vaccine in humans. The investigators have shown that normally high numbers of influenza specific antibody secreting cells (ASC) are present in the nasal mucosa of healthy adults but upon parenteral vaccination the numbers remain stable. However, a rapid transient increase in specific ASC is observed in the tonsils and peripheral blood after parenteral vaccination. In the tonsils, this is associated with a significant decrease in both naïve/effector (CD45RA+) and memory (CD45RO+) CD4+ cells upon vaccination. In this study the investigators will extend our work to investigate the characteristics of influenza-specific T- and B-cells induced locally and systemically after intranasal vaccination in man.

The clinical trial will be an open study. All subjects eligible for tonsillectomy at Haukeland University Hospital within the specified age range (children: 2 to less than 18 years old and adults >18-59 years old) will receive an invitation to join the study. The primary endpoints of the trial are the evaluation of the systemic and local immune response after live attenuated influenza vaccine. The vaccine specific immune response will be assessed through the induction of specific local and systemic antibody and cellular immune responses, and analyses of the epitopes to which the response is directed. Furthermore the capacity of the vaccine to elicit cross reactive and long lasting immunity will be evaluated.

Inclusion Criteria:

• Healthy children (age range ≥2 and <18 years old) or adults (>18-59 years old) as concluded from the medical history, physical examination, and clinical judgment) scheduled for tonsillectomy ;
• Signed informed consent from the subject or both parents/ both guardians and from subjects aged 12 years and older;
• Subjects or guardians able to understand and comply with the study protocol and complete the Adverse Event Form:
• Subjects able to attend the scheduled visits.

Exclusion Criteria:

• Persons with a history of anaphylaxis or serious reactions to any vaccine;
• Person with known hypersensitivity to any of the vaccine components (e.g. gelatin, gentamicin, eggs or egg proteins (e.g. ovalbumin);
• Persons who are pregnant
• Persons who have had a temperature >38oC during the previous 72 hours;
• Persons who have had an acute respiratory infection during the last 7 days;
• Persons who are clinically immunodeficient due to conditions or immunosuppressive therapy such as: acute and chronic leukaemias; lymphoma; symptomatic HIV infection; cellular immune deficiencies; and high-dose corticosteroids;
• Persons with severely immunocompromised family members;
• Persons with severe asthma or active wheezing.