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PLoS One. 2016 Mar 31;11(3):e0152310. doi: 10.1371/journal.pone.0152310.
Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?
Caini S1, Andrade W2, Badur S3, Balmaseda A4, Barakat A5, Bella A6, Bimohuen A5, Brammer L7, Bresee J7, Bruno A8, Castillo L9, Ciblak MA3, Clara AW10, Cohen C11,12, Cutter J13, Daouda C14, de Lozano C15, De Mora D8, Dorji K16, Emukule GO17, Fasce RA2, Feng L18, Ferreira de Almeida WA19, Guiomar R20, Heraud JM21, Holubka O22, Huang QS23, Kadjo HA14, Kiyanbekova L24, Kosasih H25, Kusznierz G26, Lara J27, Li M18, Lopez L23, Mai Hoang PV28, Pessanha Henriques CM19, Matute ML29, Mironenko A22, Moreno B30, Mott JA17, Njouom R31, Nurhayati25, Ospanova A24, Owen R32, Pebody R33, Pennington K32, Puzelli S34, Quynh Le MT28, Razanajatovo NH21, Rodrigues A35, Rudi JM26, Tzer Pin Lin R13, Venter M36,37, Vernet MA31, Wangchuk S16, Yang J18, Yu H18, Zambon M38, Schellevis F1, Paget J1; Global Influenza B Study.
Author information
Abstract
INTRODUCTION:
Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes.
METHODS:
This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics.
RESULTS:
212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics.
DISCUSSION:
Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.
PMID: 27031105 [PubMed - as supplied by publisher]
Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?
Caini S1, Andrade W2, Badur S3, Balmaseda A4, Barakat A5, Bella A6, Bimohuen A5, Brammer L7, Bresee J7, Bruno A8, Castillo L9, Ciblak MA3, Clara AW10, Cohen C11,12, Cutter J13, Daouda C14, de Lozano C15, De Mora D8, Dorji K16, Emukule GO17, Fasce RA2, Feng L18, Ferreira de Almeida WA19, Guiomar R20, Heraud JM21, Holubka O22, Huang QS23, Kadjo HA14, Kiyanbekova L24, Kosasih H25, Kusznierz G26, Lara J27, Li M18, Lopez L23, Mai Hoang PV28, Pessanha Henriques CM19, Matute ML29, Mironenko A22, Moreno B30, Mott JA17, Njouom R31, Nurhayati25, Ospanova A24, Owen R32, Pebody R33, Pennington K32, Puzelli S34, Quynh Le MT28, Razanajatovo NH21, Rodrigues A35, Rudi JM26, Tzer Pin Lin R13, Venter M36,37, Vernet MA31, Wangchuk S16, Yang J18, Yu H18, Zambon M38, Schellevis F1, Paget J1; Global Influenza B Study.
Author information
Abstract
INTRODUCTION:
Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes.
METHODS:
This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics.
RESULTS:
212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics.
DISCUSSION:
Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.
PMID: 27031105 [PubMed - as supplied by publisher]