Journal Article

Waning vaccine protection against influenza A (H3N2) illness in children and older adults during a single season

Sundaram, Maria E., McClure, David L., VanWormer, Jeffrey J., Ferdinands, Jill, Belongia, Edward A., Meece, Jennifer K.

2015

Overview

•Waning protection against influenza A (H3N2) occurred in a 2007–2008 community study.•Patients vaccinated earlier were more likely to develop H3N2 illness.•Effects were seen in young children and older adults, but not working age adults. Recent studies have suggested that vaccine-induced protection against influenza may decline within one season. We reanalyzed data from a study of influenza vaccine effectiveness to determine if time since vaccination was an independent predictor of influenza A (H3N2). Patients with acute respiratory illness were actively recruited during the 2007–2008 season. Respiratory swabs were tested for influenza, and vaccination dates were determined by a validated immunization registry. The association between influenza RT-PCR result and vaccination interval (days) was examined using multivariable logistic regression, adjusting for calendar time, age and other confounders. There were 629 vaccinated participants, including 177 influenza A (H3N2) cases and 452 test negative controls. The mean (SD) interval from vaccination to illness onset was 101.7 (25.9) days for influenza cases and 93.0 (29.9) days for controls. There was a significant association between vaccination interval and influenza result in the main effects model. The adjusted odds ratio (aOR) for influenza was 1.12 (CI 1.01, 1.26) for every 14 day increase in the vaccination interval. Age modified the association between vaccination interval and influenza (p=0.005 for interaction). Influenza was associated with increasing vaccination interval in young children and older adults, but not in adolescents or non-elderly adults. Similar results were found when calendar week of vaccine receipt was assessed as the primary exposure variable. Identification of influenza A (H3N2) was associated with increasing time since vaccination among young children and older adults during a single influenza season.

• Publisher: Elsevier Ltd,Elsevier Limited
• Subject: Adolescent / adolescents / Adult / Aged / Aged, 80 and over / Allergy and Immunology / Child / Child, Preschool / Children / elderly / Female / Humans / Illnesses / Immunity / Immunization / Infant / Influenza / Influenza A Virus, H3N2 Subtype - immunology / Influenza A Virus, H3N2 Subtype - isolation & purification / Influenza vaccine / Influenza Vaccines - administration & dosage / Influenza Vaccines - immunology / Influenza, Human - immunology / Influenza, Human - prevention & control / Male / Middle Aged / Nasopharynx - virology / odds ratio / Older people / primary contact / regression analysis / Reverse Transcriptase Polymerase Chain Reaction / Seasons / Time Factors / Treatment Outcome / vaccination / Vaccine effectiveness / Vaccines / Young Adult