Figure 3. Comparison of Influenza Vaccine Effectiveness (VE) in Alberta With Other Published Estimates by Type/Subtype, Season, and Vaccine Type3,6,7,8,20,21,22,23,24,25,26,27,28.
Vaccine effectiveness was calculated as (1 − adjusted odds ratio) × 100% for all studies except HIVE, where VE was calculated using the formula 1 – hazard ratio. All follow this formula except the results from the Household Influenza Vaccine Effectiveness Study (HIVE), where VE is calculated using the hazard ratio (HR); the formula is still (1 − HR). The threshold level of 5% weekly test positivity was used. CDC indicates Centers for Disease Control and Prevention; DoD, Department of Defense; ICICLE, Influenza Clinical Investigation for Children; IIV, inactivated influenza vaccine; LAIV, live attenuated influenza vaccine; and SPSN, Sentinel Practitioner Surveillance Network. Error bars indicate 95% CIs.
aThe lower confidence limit for the vaccine effectiveness estimate from the UK study21 is −457.