Related Experiment Video
Updated: Jun 10, 2026

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies
Published on: February 23, 2018
Clinical and immunologic predictors of influenza illness among vaccinated older adults
Zainab Shahid1, Alison Kleppinger, Beth Gentleman
1Division of Infectious Diseases, Department of Medicine, University of Connecticut Health Center, Farmington, CT, USA.
Abstract:
The diagnosis of influenza is often missed in older adults and illness presentation may be modified by prior vaccination. We evaluated the symptoms and immunologic markers predicting laboratory-confirmed influenza (LCI) among vaccinated older adults. In subjects with influenza-like illness (ILI), fever distinguished subjects with laboratory-confirmed influenza (LCI) from those with other ILI (39% vs. 12.5%, p=0.009). In LCI subjects who did not seroconvert to influenza infection, pre-infection levels of the cytolytic mediator, granzyme B, correlated with fever (r=1.000; p=0.01) and the IFN-gamma:IL-10 ratio (r=0.999; p=0.03), and increased following influenza infection in LCI vs. ILI subjects (p=0.03). The cell-mediated immune response to influenza distinguishes A/H3N2 LCI from other ILI in older adults, and suggests a link between cell-mediated immunity and influenza illness severity in vaccinated older adults.
Related Concept Videos
Vaccinations
Influenza
Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin create...
Factors Affecting Illness
For instance, risk factors are connected to illness, disability,...
Immunological Memory
What is Immunological Memory?
Immunological memory is an integral function of the immune system that allows it to recognize and react more rapidly and effectively to pathogens previously encountered. This feature is...
Pharmacodynamics in Geriatric Patients: Effects of Age

