Effectiveness of the MF59-adjuvanted trivalent or quadrivalent seasonal
influenza vaccine among adults 65 years of age or older, a systematic
review and meta-analysis
Abstract
Background: Standard dose seasonal influenza vaccines often produce
modest immunogenic responses in adults ≥65 years old. MF59 is intended
to elicit a greater magnitude and increased breadth of immune response.
Objective: To determine the effectiveness of seasonal MF59-adjuvanted
trivalent/quadrivalent influenza vaccine (aTIV/aQIV) relative to no
vaccination or vaccination with standard or high dose egg-based
influenza vaccines among people ≥65 years old. Methods: Cochrane
methodological standards and PRISMA-P guidelines were followed.
Real-world evidence from non-interventional studies published in peer
reviewed journals and grey literature from 1997 through to July 15,
2020, including cluster-randomized trials, were eligible. Two reviewers
independently extracted data and risk of bias was assessed using the
ROBINS-I tool. Results: Twenty-one studies conducted during the
2006/07-2019/20 influenza seasons were included in the qualitative
review; 16 in the meta-analyses. Meta-analysis of test-negative studies
found that aTIV reduced medical encounters due to lab-confirmed
influenza with pooled estimates of 40.7% (95% CI: 21.9, 54.9; I2=0%)
for general practitioner visits and 58.5% (40.7, 70.9; I2=52.9%) for
hospitalized patients. The pooled estimate of VE from case-control
studies was 51.3% (39.1, 61.1; I2=0%) against influenza- or
pneumonia-related hospitalization. The pooled estimates for the relative
VE of aTIV for the prevention of influenza related medical encounters
were 13.9% (4.2, 23.5; I2=95.9%) compared with TIV, 13.7% (3.1, 24.2;
I2=98.8%) compared with QIV, and 2.8% (-2.9, 8.5; I2=94.5%) compared
with HD TIV. Conclusions: Among adults ≥65 years aTIV demonstrated
significant absolute VE, improved relative VE compared to non-adjuvanted
standard-dose TIV/QIV, and comparable relative VE to high-dose TIV.