Send to

Choose Destination
J Infect Dis. 2018 Dec 18. doi: 10.1093/infdis/jiy716. [Epub ahead of print]

Relative effectiveness of cell-cultured and egg-based influenza vaccines among the U.S. elderly, 2017-18.

Author information

Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
PhD. candidate, Universidad Rey Juan Carlos, Spain.
Acumen LLC, Burlingame, CA, USA.
Centers for Medicare and Medicaid Services, Washington DC, USA.



The low influenza vaccine effectiveness (VE) observed during the A(H3N2)-dominated 2017-18 season may be due to vaccine virus adaptation to growth in eggs. We compared effectiveness of cell-cultured and egg-based vaccines among Medicare beneficiaries.


Retrospective cohort study on beneficiaries ages ≥65 years who received an influenza vaccine (cell-cultured, egg-based quadrivalent; egg-based high-dose, adjuvanted, or standard-dose trivalent) during the 2017-18 season. We used Poisson regression to evaluate relative VE (RVE) in preventing influenza hospital encounters.


Of >13 million beneficiaries, RVE for cell-cultured vaccines relative to egg-based quadrivalent vaccines was 10% (95% CI: 7% to 13%). In a mid-season interim analysis, this estimate was 16.5% (95% CI: 10.3% to 22.2%). In a five-way comparison, cell-cultured (RVE 11%, 95% CI: 8% to 14%) and egg-based high-dose (RVE 8%, 95% CI: 7% to 10%) vaccines were more effective than egg-based quadrivalent vaccines.

Conclusions :

he modest VE difference between cell-cultured and egg-based vaccines only partially explains the low overall VE reported by CDC, suggesting egg adaptation was not the main contributor to the low VE found among individuals ages ≥65 years. The mid-season interim analysis we performed demonstrates that our methods can be used to evaluate VE actively during the flu season.


Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center