@article{fdi:010096875,
  title = {{S}ocial mixing patterns and {C}hikungunya reemergence risk in {F}rench {P}olynesia},
  author = {{C}hung, {K}. {K}. and {A}ubry, {M}. and {T}eiti, {I}. and {M}apotoeke, {M}. and {W}hite, {R}. and {B}ossin, {H}. and {M}athieu-{D}aud{\'e}, {F}ran{\c{c}}oise and {D}ian, {L}. and {P}aoaafaite, {T}. and {W}attiaux, {A}. and {M}allet, {H}. {P}. and {V}anhomwegen, {J}. and {M}anuguerra, {J}. {C}. and {K}ucharski, {A}. and {C}ao-{L}ormeau, {V}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}mportance {C}hikungunya virus has reemerged in some {F}rench overseas territories and mainland {F}rance, raising concern for its reintroduction in {F}rench {P}olynesia. {O}bjective {T}o assess current population immunity to chikungunya virus and estimate future outbreak risk. {D}esign, {S}etting, and {P}articipants {T}his cross-sectional study included data from 2 serosurveys and used a modeling approach that integrated seroprevalence, contact matrices, and demographic characteristics. {T}he first serosurvey was conducted on the island of {T}ahiti ({J}une 2018) among schoolchildren aged 6 to 16 years. {T}he second serosurvey ({N}ovember 2019 to {D}ecember 2021) included adults aged 18 to 69 years across {F}rench {P}olynesia, a {F}rench overseas territory in the {S}outheast {P}acific that comprises 75 inhabited islands grouped into 5 subdivisions with 279 000 people according to the 2022 census. {D}ata analysis was conducted from {A}pril to {J}une 2025. {M}ain {O}utcomes and {M}easures {M}ain outcomes were seroprevalence rates and factors associated with seropositivity; age-stratified infection proportions for the 2014 to 2015 outbreak, pre-outbreak the basic reproduction number ({R}-0), the effective reproduction number ({R}-eff) for 2025, and {R}-eff projections were estimated. {R}esults {S}erological data were available for 2363 participants (457 schoolchildren; median [{IQR}] age, 11 [8-13] years; 244 [53.3%] female, and 1906 adults; 38 [28-52] years; 1003 [52.6%] female). {S}eroprevalence was 62.8% (95% {CI}, 58.0%-67.0%) in schoolchildren, and the weighted seroprevalence was 67.6% (95% {CI}, 64.8%-70.3%) in adults. {I}n adults, lower odds of seropositivity were associated with male sex (adjusted odds ratio [a{OR}], 0.71; 95% {CI}, 0.55-0.92), age groups 30 to 44 years and 45 to 69 years compared with 18 to 29 years (ages 30-44 years: a{OR}, 0.46; 95% {CI}, 0.32-0.66; ages 45-69 years: a{OR}, 0.33; 95% {CI}, 0.22-0.48), living in the {A}ustral subdivision (a{OR}, 0.38; 95% {CI}, 0.27-0.55), and higher education (ie, university or more education: a{OR}, 0.51; 95% {CI}, 0.32-0.81). {L}iving in larger households and being unpartnered were associated with higher odds of seropositivity (larger households: a{OR}, 1.69; 95% {CI}, 1.12-2.56; being unpartnered: a{OR}, 1.95; 95% {CI}, 1.03-3.69). {M}odeled infection rates for 2014 to 2015 ranged from 52.6% (95% credible interval [{C}r{I}], 43.6%-60.0%) in children aged 0 to 4 years to 80.8% (95% {C}r{I}, 73.3%-86.2%) in those aged 10 to 14 years. {I}nferred pre-outbreak {R}-0 was 1.78 (95% {C}r{I}, 1.73-1.82), and {R}-eff for 2025 was estimated at 0.95 (95% {C}r{I}, 0.85-1.04). {A}ssuming assortative mixing, projections suggest {R}-eff would exceed 1 (lower 95% {C}r{I} >1) by 2028, but assuming random mixing, {R}-eff would exceed 1 in 2051, more than 20 years later than the other estimate. {C}onclusions and {R}elevance {I}n this cross-sectional study, high chikungunya seroprevalence was observed, with heterogeneity between subdivisions, age groups, and other sociodemographic characteristics. {M}odeling analysis estimated {R}-eff near 1 in 2025, suggesting sustained transmission could occur if chikungunya is reintroduced. {T}hese findings suggest that incorporating contact matrices could improve outbreak risk assessments, while assuming random mixing might underestimate reemergence timing.},
  keywords = {{POLYNESIE} {FRANCAISE}},
  booktitle = {},
  journal = {{JAMA} {N}etwork {O}pen},
  volume = {9},
  numero = {3},
  pages = {e262270 [15 p.]},
  ISSN = {2574-3805},
  year = {2026},
  DOI = {10.1001/jamanetworkopen.2026.2270},
  URL = {https://www.documentation.ird.fr/hor/fdi:010096875},
}