Rationale and Background: Since 2013, Butantan Institute has been performing passive pharmacovigilance activities related to its triavalent, fragmented and inactivated vaccine (IB TIV).

Objetive: To conduct an active surveillance study focusing on the elderly and health care professionals as part of Butantan pharmacovigilance plan, while passive surveillance activities will continue. The pharmacovigilance plan, via active surveillance, is being implemented in response to WHO requirements for pre-qualification of IB TIV.

Study Design: This is a prospective cohort study. Population: Target groups for vaccination defined by The National Immunization Program of Brazil: healthcare workers and elderly (people over 60 years old). Study Size: A total of 400 individuals (150 health care workers and 250 elderly), presenting for immunization with IB TIV, and who agree to participate after providing Informed Consent.

Inclusion Criteria:

• Health Care Professional; or
• Elderly (age 60 or more); and
• To have indication to be vaccinated against influenza, according the the Brazilian National Immunazition Programme; and
• To be available to participate in the study throughout its duration (6 weeks after any vaccine dose administered); and
• To demonstrates interest to participate in the study as registered in the informed consent form (ICF).

Exclusion Criteria:

• Known systemic hypersensitivity to eggs or to any component of the vaccine;
• Suspected or confirmed fever in the 3 days prior to vaccination or axillary temperature greater than 37.8 ° C on the day of vaccination;
• History of severe adverse reaction after previous administration of an Influenza vaccine within 6 weeks following vaccination;
• History of Guillain-Barre Syndrome or other demyelinating disease;
• Behavioral, cognitive or psychiatric disease that in the opinion of the principal investigator or his representative physician, affects the participant ability to understand and cooperate with all study protocol requirements;
• Any other condition in the opinion of the investigator that justifies exclusion from participation.

People eligible for immunization with seasonal influenza vaccine, focusing on: elderly and health care workers.