@article{fdi:010065526,
  title = {{S}easonality of absolute humidity explains seasonality of influenza-like illness in {V}ietnam},
  author = {{T}hai, {P}. {Q}. and {C}hoisy, {M}arc and {D}uong, {T}. {N}. and {T}hiem, {V}. {D}. and {Y}en, {N}. {T}. and {H}ien, {N}. {T}. and {W}eiss, {D}. {J}. and {B}oni, {M}. {F}. and {H}orby, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground: {E}xperimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. {I}n particular, low absolute humidity ({AH}) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. {H}ere, we aim to study the potential climatic drivers of influenza-like illness ({ILI}) epidemiology in {V}ietnam, a tropical country characterized by a high diversity of climates. {W}e specifically focus on quantifying and explaining the seasonality of {ILI}. {M}ethods: {W}e used 18 years (1993-2010) of monthly {ILI} notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across {V}ietnam. {S}easonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. {T}he 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of {AH}. {R}esults were extrapolated to the global scale using simulated climatic times series from the {NCEP}/{NCAR} project. {R}esults: {T}he intensity of {ILI} seasonality in {V}ietnam is best explained by the intensity of {AH} seasonality. {W}e find that {ILI} seasonality is weak in provinces experiencing weak seasonal fluctuations in {AH} (annual power <17.6), whereas {ILI} seasonality is strongest in provinces with pronounced {AH} seasonality (power >17.6). {I}n {V}ietnam, {AH} and {ILI} are positively correlated. {C}onclusions: {O}ur results identify a role for {AH} in driving the epidemiology of {ILI} in a tropical setting. {H}owever, in contrast to temperate regions, high rather than low {AH} is associated with increased {ILI} activity. {F}luctuation in {AH} may be the climate factor that underlies and unifies the seasonality of {ILI} in both temperate and tropical regions. {A}lternatively, the mechanism of action of {AH} on disease transmission may be different in cold-dry versus hot-humid settings.},
  keywords = {{A}bsolute humidity ; {I}nfluenza like illness ; {S}easonality ; {R}egression tree ; {V}ietnam ; {VIET} {NAM}},
  booktitle = {},
  journal = {{E}pidemics},
  volume = {13},
  numero = {},
  pages = {65--73},
  ISSN = {1755-4365},
  year = {2015},
  DOI = {10.1016/j.epidem.2015.06.002},
  URL = {https://www.documentation.ird.fr/hor/fdi:010065526},
}