• Talbot HK, Nian H, Chen Q, Zhu Y, Edwards KM, Griffin MR. Evaluating the case-positive, control test-negative study design for influenza vaccine effectiveness for the frailty bias. Vaccine. 2016 Apr 4;34(15). 1806-9. PMID: 26930368 [PubMed]. PMCID: PMC4801768. NIHMSID: NIHMS763132.

Abstract 

Previous influenza vaccine effectiveness studies were criticized for their failure to control for frailty. This study was designed to see if the test-negative study design overcomes this bias.