Nonannual seasonality of influenza-like illness in a tropical urban setting

Ha Minh Lam, Amy Wesolowski, Nguyen Thanh Hung, Tran Dang Nguyen, Nguyen Thi Duy Nhat, Stacy Todd, Dao Nguyen Vinh, Nguyen Ha Thao Vy, Tran Thi Nhu Thao, Nguyen Thi Le Thanh, Phan Tri Tin, Ngo Ngoc Quang Minh, Juliet E. Bryant, Caroline O. Buckee, Tran Van Ngoc, Nguyen Van Vinh Chau, Guy E. Thwaites, Jeremy Farrar, Dong Thi Hoai Tam, Ha VinhMaciej F. Boni

Research output: Contribution to journalArticle

Abstract

Background: In temperate and subtropical climates, respiratory diseases exhibit seasonal peaks in winter. In the tropics, with no winter, peak timings are irregular. Methods: To obtain a detailed picture of influenza-like illness (ILI) patterns in the tropics, we established an mHealth study in community clinics in Ho Chi Minh City (HCMC). During 2009-2015, clinics reported daily case numbers via SMS, with a subset performing molecular diagnostics for influenza virus. This real-time epidemiology network absorbs 6000 ILI reports annually, one or two orders of magnitude more than typical surveillance systems. A real-time online ILI indicator was developed to inform clinicians of the daily ILI activity in HCMC. Results: From August 2009 to December 2015, 63 clinics were enrolled and 36 920 SMS reports were received, covering approximately 1.7M outpatient visits. Approximately 10.6% of outpatients met the ILI case definition. ILI activity in HCMC exhibited strong nonannual dynamics with a dominant periodicity of 206 days. This was confirmed by time series decomposition, stepwise regression, and a forecasting exercise showing that median forecasting errors are 30%-40% lower when using a 206-day cycle. In ILI patients from whom nasopharyngeal swabs were taken, 31.2% were positive for influenza. There was no correlation between the ILI time series and the time series of influenza, influenza A, or influenza B (all P > 0.15). Conclusion: This suggests, for the first time, that a nonannual cycle may be an essential driver of respiratory disease dynamics in the tropics. An immunological interference hypothesis is discussed as a potential underlying mechanism.

Original languageEnglish (US)
Pages (from-to)742-754
Number of pages13
JournalInfluenza and other Respiratory Viruses
Volume12
Issue number6
DOIs
StatePublished - Nov 2018

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Human Influenza
Outpatients
Molecular Pathology
Telemedicine
Periodicity
Orthomyxoviridae
Climate
Epidemiology
Exercise

All Science Journal Classification (ASJC) codes

  • Epidemiology
  • Pulmonary and Respiratory Medicine
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

Cite this

Lam, Ha Minh ; Wesolowski, Amy ; Hung, Nguyen Thanh ; Nguyen, Tran Dang ; Nhat, Nguyen Thi Duy ; Todd, Stacy ; Vinh, Dao Nguyen ; Vy, Nguyen Ha Thao ; Thao, Tran Thi Nhu ; Thanh, Nguyen Thi Le ; Tin, Phan Tri ; Minh, Ngo Ngoc Quang ; Bryant, Juliet E. ; Buckee, Caroline O. ; Ngoc, Tran Van ; Chau, Nguyen Van Vinh ; Thwaites, Guy E. ; Farrar, Jeremy ; Tam, Dong Thi Hoai ; Vinh, Ha ; Boni, Maciej F. / Nonannual seasonality of influenza-like illness in a tropical urban setting. In: Influenza and other Respiratory Viruses. 2018 ; Vol. 12, No. 6. pp. 742-754.
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abstract = "Background: In temperate and subtropical climates, respiratory diseases exhibit seasonal peaks in winter. In the tropics, with no winter, peak timings are irregular. Methods: To obtain a detailed picture of influenza-like illness (ILI) patterns in the tropics, we established an mHealth study in community clinics in Ho Chi Minh City (HCMC). During 2009-2015, clinics reported daily case numbers via SMS, with a subset performing molecular diagnostics for influenza virus. This real-time epidemiology network absorbs 6000 ILI reports annually, one or two orders of magnitude more than typical surveillance systems. A real-time online ILI indicator was developed to inform clinicians of the daily ILI activity in HCMC. Results: From August 2009 to December 2015, 63 clinics were enrolled and 36 920 SMS reports were received, covering approximately 1.7M outpatient visits. Approximately 10.6{\%} of outpatients met the ILI case definition. ILI activity in HCMC exhibited strong nonannual dynamics with a dominant periodicity of 206 days. This was confirmed by time series decomposition, stepwise regression, and a forecasting exercise showing that median forecasting errors are 30{\%}-40{\%} lower when using a 206-day cycle. In ILI patients from whom nasopharyngeal swabs were taken, 31.2{\%} were positive for influenza. There was no correlation between the ILI time series and the time series of influenza, influenza A, or influenza B (all P > 0.15). Conclusion: This suggests, for the first time, that a nonannual cycle may be an essential driver of respiratory disease dynamics in the tropics. An immunological interference hypothesis is discussed as a potential underlying mechanism.",
author = "Lam, {Ha Minh} and Amy Wesolowski and Hung, {Nguyen Thanh} and Nguyen, {Tran Dang} and Nhat, {Nguyen Thi Duy} and Stacy Todd and Vinh, {Dao Nguyen} and Vy, {Nguyen Ha Thao} and Thao, {Tran Thi Nhu} and Thanh, {Nguyen Thi Le} and Tin, {Phan Tri} and Minh, {Ngo Ngoc Quang} and Bryant, {Juliet E.} and Buckee, {Caroline O.} and Ngoc, {Tran Van} and Chau, {Nguyen Van Vinh} and Thwaites, {Guy E.} and Jeremy Farrar and Tam, {Dong Thi Hoai} and Ha Vinh and Boni, {Maciej F.}",
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Lam, HM, Wesolowski, A, Hung, NT, Nguyen, TD, Nhat, NTD, Todd, S, Vinh, DN, Vy, NHT, Thao, TTN, Thanh, NTL, Tin, PT, Minh, NNQ, Bryant, JE, Buckee, CO, Ngoc, TV, Chau, NVV, Thwaites, GE, Farrar, J, Tam, DTH, Vinh, H & Boni, MF 2018, 'Nonannual seasonality of influenza-like illness in a tropical urban setting', Influenza and other Respiratory Viruses, vol. 12, no. 6, pp. 742-754. https://doi.org/10.1111/irv.12595

Nonannual seasonality of influenza-like illness in a tropical urban setting. / Lam, Ha Minh; Wesolowski, Amy; Hung, Nguyen Thanh; Nguyen, Tran Dang; Nhat, Nguyen Thi Duy; Todd, Stacy; Vinh, Dao Nguyen; Vy, Nguyen Ha Thao; Thao, Tran Thi Nhu; Thanh, Nguyen Thi Le; Tin, Phan Tri; Minh, Ngo Ngoc Quang; Bryant, Juliet E.; Buckee, Caroline O.; Ngoc, Tran Van; Chau, Nguyen Van Vinh; Thwaites, Guy E.; Farrar, Jeremy; Tam, Dong Thi Hoai; Vinh, Ha; Boni, Maciej F.

In: Influenza and other Respiratory Viruses, Vol. 12, No. 6, 11.2018, p. 742-754.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Nonannual seasonality of influenza-like illness in a tropical urban setting

AU - Lam, Ha Minh

AU - Wesolowski, Amy

AU - Hung, Nguyen Thanh

AU - Nguyen, Tran Dang

AU - Nhat, Nguyen Thi Duy

AU - Todd, Stacy

AU - Vinh, Dao Nguyen

AU - Vy, Nguyen Ha Thao

AU - Thao, Tran Thi Nhu

AU - Thanh, Nguyen Thi Le

AU - Tin, Phan Tri

AU - Minh, Ngo Ngoc Quang

AU - Bryant, Juliet E.

AU - Buckee, Caroline O.

AU - Ngoc, Tran Van

AU - Chau, Nguyen Van Vinh

AU - Thwaites, Guy E.

AU - Farrar, Jeremy

AU - Tam, Dong Thi Hoai

AU - Vinh, Ha

AU - Boni, Maciej F.

PY - 2018/11

Y1 - 2018/11

N2 - Background: In temperate and subtropical climates, respiratory diseases exhibit seasonal peaks in winter. In the tropics, with no winter, peak timings are irregular. Methods: To obtain a detailed picture of influenza-like illness (ILI) patterns in the tropics, we established an mHealth study in community clinics in Ho Chi Minh City (HCMC). During 2009-2015, clinics reported daily case numbers via SMS, with a subset performing molecular diagnostics for influenza virus. This real-time epidemiology network absorbs 6000 ILI reports annually, one or two orders of magnitude more than typical surveillance systems. A real-time online ILI indicator was developed to inform clinicians of the daily ILI activity in HCMC. Results: From August 2009 to December 2015, 63 clinics were enrolled and 36 920 SMS reports were received, covering approximately 1.7M outpatient visits. Approximately 10.6% of outpatients met the ILI case definition. ILI activity in HCMC exhibited strong nonannual dynamics with a dominant periodicity of 206 days. This was confirmed by time series decomposition, stepwise regression, and a forecasting exercise showing that median forecasting errors are 30%-40% lower when using a 206-day cycle. In ILI patients from whom nasopharyngeal swabs were taken, 31.2% were positive for influenza. There was no correlation between the ILI time series and the time series of influenza, influenza A, or influenza B (all P > 0.15). Conclusion: This suggests, for the first time, that a nonannual cycle may be an essential driver of respiratory disease dynamics in the tropics. An immunological interference hypothesis is discussed as a potential underlying mechanism.

AB - Background: In temperate and subtropical climates, respiratory diseases exhibit seasonal peaks in winter. In the tropics, with no winter, peak timings are irregular. Methods: To obtain a detailed picture of influenza-like illness (ILI) patterns in the tropics, we established an mHealth study in community clinics in Ho Chi Minh City (HCMC). During 2009-2015, clinics reported daily case numbers via SMS, with a subset performing molecular diagnostics for influenza virus. This real-time epidemiology network absorbs 6000 ILI reports annually, one or two orders of magnitude more than typical surveillance systems. A real-time online ILI indicator was developed to inform clinicians of the daily ILI activity in HCMC. Results: From August 2009 to December 2015, 63 clinics were enrolled and 36 920 SMS reports were received, covering approximately 1.7M outpatient visits. Approximately 10.6% of outpatients met the ILI case definition. ILI activity in HCMC exhibited strong nonannual dynamics with a dominant periodicity of 206 days. This was confirmed by time series decomposition, stepwise regression, and a forecasting exercise showing that median forecasting errors are 30%-40% lower when using a 206-day cycle. In ILI patients from whom nasopharyngeal swabs were taken, 31.2% were positive for influenza. There was no correlation between the ILI time series and the time series of influenza, influenza A, or influenza B (all P > 0.15). Conclusion: This suggests, for the first time, that a nonannual cycle may be an essential driver of respiratory disease dynamics in the tropics. An immunological interference hypothesis is discussed as a potential underlying mechanism.

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DO - 10.1111/irv.12595

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