Post-licensure observational safety study of specific outcomes after Optaflu vaccination among adults in The Health Improvement Network (THIN) database of routine UK primary care records (V58_30OB (FLUPASS1))

Study type

• Study topic:
  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Assessment of risk minimisation measure implementation or effectiveness
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Other
• Non-interventional study design, other:
  Observed-to-expected analysis and estimation of incidence in an exposed population.

Study drug and medical condition

• Medicinal product name, other:
  Cell culture trivalent influenza vaccine (Optaflu)

Population studied

• Short description of the study population:
  All permanently registered patients 18 years of age and over with a record on THIN that they have received at least one dose of cTIV vaccine as a seasonal influenza vaccination between September 2012 and March 2014 inclusive.
• Age groups:
  • Adults (18 to < 46 years)
  • Adults (46 to < 65 years)
  • Adults (65 to < 75 years)
  • Adults (75 to < 85 years)
  • Adults (85 years and over)
• Estimated number of subjects:
  9000

Study design details

• Main study objective:
  To investigate the safety of cTIV vaccination in adults in routine clinical care in the UK with regard to pre-specified outcomes.
• Outcomes:
  Anaphylactic reactions and angioedema, Bell’s palsy, convulsions, demyelination including GBS, neuritis (optic and brachial), non-infectious encephalitis, thrombocytopenia, vasculitis, paraesthesia and inflammatory bowel disease will be studied
• Data analysis plan:
  Study outcomes will be identified from three months before vaccination until six months afterwards. Temporal plots will be prepared which show the distribution of each study outcome in relation to the vaccination date in pre-defined risk-windows. These risk-windows will be based on the biologically plausible time frame when an outcome caused by the vaccine might be expected to occur. If an outcome occurs in the risk window, the ratio of observed to expected cases will be calculated to investigate if a signal of an association between cTIV exposure and a study outcome has been generated. The observed rates will be those in the risk window and the expected will be from outside this period. The incidence of each study outcome in the six months after vaccination, in age and sex categories will also be calculated.