Figure 1.
Map of 137 studied locations, for which information was retrieved on the seasonality of influenza or RSV viral activity (blue dot = influenza study, red dot = RSV study, yellow dot = both influenza and RSV information were available from the same study).
Table 1.
Summary of information retrieved on influenza and respiratory syncytial virus (RSV) viral activity by literature search and queries of electronic surveillance websites providing sub-national data.
Figure 2.
Global map of influenza peak timing and epidemic duration (n = 77 locations).
Colors illustrate timing of peak influenza activity, based on the bottom left key, while size of the circles is proportional to epidemic duration. For independent observations for the same location, an average was taken. For studies that did not provide enough information to estimate duration, a triangle is shown. Circles filled out with more than one color represent locations experiencing semi-annual peaks of virus activity (methods).
Figure 3.
Distribution of influenza peak month by geographic zone (n = 77 locations).
The black histogram represents observations while the red curve illustrates the fit of a Gaussian density kernel.
Table 2.
Influenza and respiratory syncytial virus (RSV) peak timing and epidemic duration by geographic zone.
Table 3.
Association between absolute latitude, peak timing, and duration of influenza and respiratory syncytial virus (RSV) epidemics, by geographic zone.
Figure 4.
Global map of RSV peak timing and epidemic duration (n = 96 locations).
Colors illustrate timing of peak RSV activity, based on the bottom left key, while size of the circles is proportional to epidemic duration. Independent observations for the same location were averaged out. For studies that did not provide enough information to estimate duration, a triangle is shown. Circles filled out with more than one color represent locations experiencing semi-annual peaks of virus activity (methods).
Figure 5.
Distribution of RSV peak month by geographic zone (n = 96 locations).
The black histogram represents observations while the red curve illustrates the fit of a Gaussian density kernel.
Figure 6.
Latitudinal gradients in the seasonal amplitude, timing, and duration of influenza epidemics, based on time series modeling of weekly influenza virus surveillance data from 85 countries reporting to FluNet.
Analysis was limited to countries providing ≥30 viruses for ≥3 yrs. Different colors represent different continents (blue = Europe; red = America; green = Asia-Pacific; black = Africa). Horizontal grey bars represent estimation error (top panels) or between-year fluctuation in seasonal characteristics (bottom panels, ±2 standard deviations).