Latitudinal Variations in Seasonal Activity of Influenza and Respiratory Syncytial Virus (RSV): A Global Comparative Review

• DOI: 10.1371/journal.pone.0054445
• Publication Date: 2013-02-14T22:00:26Z
• Authors: Kimberly Bloom-Fe...; Wladimir J. Alonso; Vivek Charu; James Tamerius; Lone Simonsen; Mark A. Miller; Cécile Viboud
• Keywords: Seasonality; Seasonal influenza; Pneumovirinae

There is limited information on influenza and respiratory syncytial virus (RSV) seasonal patterns in tropical areas, although there renewed interest understanding the drivers of viruses.We review geographic variations seasonality laboratory-confirmed RSV epidemics 137 global locations based literature electronic sources. We assessed peak timing epidemic duration explored their association with geography study settings. fitted time series model to weekly national data available from WHO surveillance system (FluNet) further characterize parameters.Influenza activity consistently peaked during winter months temperate locales, while was greater diversity tropics. Several experienced semi-annual peaks occurring summer. Semi-annual relatively common areas Southeast Asia for both viruses. Biennial cycles were identified Northern Europe. Both viruses exhibited weak latitudinal gradients by hemisphere, later calendar year increasing latitude (P<0.03). Time applied 85 countries confirmed presence timing, duration, amplitude, between-year variability epidemics. Overall, 80% distinct seasons lasting 6 or less, percentage 50% influenza.Our combining sources suggests that a large fraction experience focused individual years. Information remains undersampled regions, included Africa Central America. Future studies should attempt link observed viral climatic population factors, explore regional differences disease transmission dynamics attack rates.