Comparative Effectiveness of High-Dose Versus Standard-Dose Influenza Vaccines Among US Medicare Beneficiaries in Preventing Postinfluenza Deaths During 2012-2013 and 2013-2014.
Recipients of high-dose vs standard-dose influenza vaccines have fewer influenza illnesses. We evaluated the comparative effectiveness of high-dose vaccine in preventing postinfluenza deaths during 2012-2013 and 2013-2014, when influenza viruses and vaccines were similar.



We identified Medicare beneficiaries aged ≥65 years who received high-dose or standard-dose vaccines in community-located pharmacies offering both vaccines. The primary outcome was death in the 30 days following an inpatient or emergency department encounter listing an influenza International of Classification of Diseases, Ninth Revision, Clinical Modification code. Effectiveness was estimated by using multivariate Poisson regression models; effectiveness was allowed to vary by season.



We studied 1039645 recipients of high-dose and 1683264 recipients of standard-dose vaccines during 2012-2013, and 1508176 high-dose and 1877327 standard-dose recipients during 2013-2014. Vaccinees were well-balanced for medical conditions and indicators of frail health. Rates of postinfluenza death were 0.028 and 0.038/10000 person-weeks in high-dose and standard-dose recipients, respectively. Comparative effectiveness was 24.0% (95% confidence interval [CI], .6%-42%); there was evidence of variation by season (P = .12). In 2012-2013, high-dose was 36.4% (95% CI, 9.0%-56%) more effective in reducing mortality; in 2013-2014, it was 2.5% (95% CI, -47% to 35%).



High-dose vaccine was significantly more effective in preventing postinfluenza deaths in 2012-2013, when A(H3N2) circulation was common, but not in 2013-2014.
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
David K
DK
Shay
Acumen LLC, Burlingame, California, USA.
Yoganand
Y
Chillarige
Centers for Medicare and Medicaid Services, Washington, District of Columbia, USA.
Jeffrey
J
Kelman
Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
Richard A
RA
Forshee
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.|Battelle Memorial Institute, Atlanta, Georgia, USA.
Ivo M
IM
Foppa
Acumen LLC, Burlingame, California, USA.
Michael
M
Wernecke
Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
Yun
Y
Lu
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Jill M
JM
Ferdinands
Acumen LLC, Burlingame, California, USA.
Arjun
A
Iyengar
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Alicia M
AM
Fry
Centers for Medicare and Medicaid Services, Washington, District of Columbia, USA.
Chris
C
Worrall
Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.|Department of Health Sciences, Universidad Rey Juan Carlos, Madrid, Spain.
Hector S
HS
Izurieta
D000368:Aged; D000369:Aged, 80 and over; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000627:therapeutic use; D007251:Influenza, Human / Q000401:mortality* / Q000517:prevention & control*; D008297:Male; D006278:Medicare; D012307:Risk Factors; D012621:Seasons; D016896:Treatment Outcome; D014481:United States
D007252:Influenza Vaccines
comparative effectiveness; human; influenza; influenza vaccines; death