Timing of influenza epidemics and vaccines in the American tropics, 2002-2008, 2011-2014

Lizette Olga Durand, Po-Yung Cheng, Rakhee Palekar, Wilfrido Clara, Jorge Jara, Mauricio Cerpa, Nathalie El Omeiri, Alba Maria Ropero-Alvarez, Juliana Barbosa Ramirez, Jenny Lara Araya, Belsy Acosta, Alfredo Bruno, Celina Calderon de Lozano, Leticia Del Carmen Castillo Signor, Maria Luisa Matute, Sandra Jackson-Betty, Kam Suan Mung, José Alberto Díaz-Quiñonez, Irma López-Martinez, Angel BalmasedaBrechla Morneo Arévalo, Cynthia Vazquez, Victoria Gutierrez, Rebecca Garten, Marc-Alain Widdowson, Eduardo Azziz-Baumgartner

Research output: Contribution to journalA1: Web of Science-articlepeer-review

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BACKGROUND: Influenza-associated illness results in increased morbidity and mortality in the Americas. These effects can be mitigated with an appropriately chosen and timed influenza vaccination campaign. To provide guidance in choosing the most suitable vaccine formulation and timing of administration, it is necessary to understand the timing of influenza seasonal epidemics.

OBJECTIVES: Our main objective was to determine whether influenza occurs in seasonal patterns in the American tropics and when these patterns occurred.

METHODS: Publicly available, monthly seasonal influenza data from the Pan American Health Organization and WHO, from countries in the American tropics, were obtained during 2002-2008 and 2011-2014 (excluding unseasonal pandemic activity during 2009-2010). For each country, we calculated the monthly proportion of samples that tested positive for influenza. We applied the monthly proportion data to a logistic regression model for each country.

RESULTS: We analyzed 2002-2008 and 2011-2014 influenza surveillance data from the American tropics and identified 13 (81%) of 16 countries with influenza epidemics that, on average, started during May and lasted 4 months.

CONCLUSIONS: The majority of countries in the American tropics have seasonal epidemics that start in May. Officials in these countries should consider the impact of vaccinating persons during April with the Southern Hemisphere formulation.

Original languageEnglish
JournalInfluenza and Other Respiratory Viruses
Issue number3
Pages (from-to)170-5
Number of pages6
Publication statusPublished - 2016


  • Brazil/epidemiology
  • Epidemiological Monitoring
  • Humans
  • Influenza Vaccines/chemistry
  • Influenza, Human/epidemiology
  • Nicaragua/epidemiology
  • Pandemics/prevention & control
  • Peru/epidemiology
  • Population Surveillance
  • Seasons
  • Time Factors
  • Tropical Climate
  • United States/epidemiology
  • Vaccination


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