@article{PAR00014094,
  title = {{A}ntibody persistence and serological protection among seasonal 2007 influenza {A}({H}1{N}1) infected subjects : results from the {FLUREC} cohort study},
  author = {{D}elabre, {R}. {M}. and {S}alez, {N}. and {L}emaitre, {M}. {L}. and {L}eruez-{V}ille, {M}. and de {L}amballerie, {X}avier and {C}arrat, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}ntroduction: {H}aemagglutination-inhibition ({HI}) antibody titer is a correlate of protection against influenza; its persistence after infection or vaccination is important to determining susceptibility to subsequent infection. {F}ew studies, however, have reported longitudinal data regarding the magnitude and duration of {HI} protection following natural seasonal influenza {A} infection. {M}ethods: {U}sing {F}rench influenza cohort study data collected from 2008 to 2010, we investigated persistence of serological protection among subjects according to influenza-like illness ({ILI}) and laboratory-confirmed seasonal 2007 influenza {A}({H}1{N}1) infection status at inclusion in 2008 ({ILI}-{A}({H}1{N}1) positive, {ILI}-{A}({H}1{N}1) negative, or no-{ILI}). {A}ntibody titers against seasonal 2007 {A}({H}1{N}1) were determined using the {HI} technique for sera. {R}egression models for interval-censored data were used to estimate geometric mean titers ({GMT}) for {HI} assays. {A} logistic regression model adjusted for age group (subjects <30, 30-50 and >50 years old) was used to quantify the association between {HI} titer and protection against infection. {R}esults: {B}ased on 310 total subjects, influenza {A}({H}1{N}1) infection was confirmed in 39 of 115 {ILI} subjects at inclusion. {GMT} associated with 50% probability of protection among {ILI} subjects decreased with age group (subjects <30 yo: {GMT} of 40.8 was associated with 50% [95{CI}: 29.3%; 70.7%] probability of protection, subjects 30-50 yo: 26.8 [95{CI}: 34.4%; 65.6%] and subjects >50 yo: 8.9 [95{CI}: 15.3%; 84.7%]). {GMT} declined after the first annual study visit among {ILI}-{A}({H}1{N}1) positive subjects but remained higher compared to inclusion at the 2010 study visit (41.5 [95{CI}: 34.8; 49.5], p = 0.0157). {GMT} remained stable among {ILI}-{A}({H}1{N}1) negative subjects (p = 0.7502), but decreased among no-{ILI} subjects (p<0.0001). {C}onclusion: {O}ur results confirm the positive relationship between {HI} titer and probability of protection among naturally infected subjects, and provides evidence that protection associated with {HI} titer varies with age. {T}his longitudinal analysis suggests the rise in {HI} titers following seasonal 2007 influenza {A}({H}1{N}1) infection may persist into subsequent influenza seasons.},
  keywords = {{A}ntibody ; {C}ohort studies ; {C}orrelate ; {I}mmunity ; {I}nfluenza {A} virus, {H}1{N}1 subtype ; {FRANCE}},
  booktitle = {},
  journal = {{V}accine},
  volume = {33},
  numero = {49},
  pages = {7015--7021},
  ISSN = {0264-410{X}},
  year = {2015},
  DOI = {10.1016/j.vaccine.2015.09.016},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00014094},
}