Heat map of monthly influenza virus incidence patterns, 2003–2014, sorted by latitude.

<p>The Global Influenza B Study, Latin-American countries, 2003–2014.</p

Countries and sub-national regions that were included in the analysis.

<p><b>The Global Influenza B Study, Latin-American countries, 2003–2014</b>. Dark Blue: Central America. Light Blue: Brazil. Yellow: remaining sites in South America.</p

Main features of influenza surveillance systems of countries and sub-national regions included in the analysis.

<p>The Global Influenza B Study, Latin-American countries, 2003–2014.</p

Timing and amplitude of primary (circles) and secondary (triangles) peak of influenza detection by site, against their latitudinal position.

<p><b>The size corresponds to the amplitude of influenza seasonality</b>. Dark Blue: Central America. Light Blue: Brazil. Yellow: remaining sites in South America.</p

Timing and amplitude of primary and secondary peaks of seasonal influenza epidemics.

<p>The Global Influenza B Study, Latin-American countries, 2003–2014.</p

Mean percentage of influenza cases by month (black diamonds) and number of times the peak of the influenza season took place in each month (pink squares) for countries of Northern hemisphere.

<p>Mean percentage of influenza cases by month (black diamonds) and number of times the peak of the influenza season took place in each month (pink squares) for countries of Northern hemisphere.</p

Influenza cases reported to the national influenza surveillance system by each participating country (from southern- to northern-most) and percentages of cases due to influenza type B virus.

<p>Influenza cases reported to the national influenza surveillance system by each participating country (from southern- to northern-most) and percentages of cases due to influenza type B virus.</p

Median percentage of influenza cases that occurred during the 3-month peak period and median number of months to have ≥80% of influenza cases during a season by zone (Southern hemisphere, inter-tropical belt, Northern hemisphere) and proportion of influenza B.

<p>Median percentage of influenza cases that occurred during the 3-month peak period and median number of months to have ≥80% of influenza cases during a season by zone (Southern hemisphere, inter-tropical belt, Northern hemisphere) and proportion of influenza B.</p

Mean percentage of influenza cases by month (black diamonds) and number of times the peak of the influenza season took place in each month (pink squares) for countries in the inter-tropical belt.

<p>Mean percentage of influenza cases by month (black diamonds) and number of times the peak of the influenza season took place in each month (pink squares) for countries in the inter-tropical belt.</p

Median percentage of influenza cases that occurred during the 3-month peak period and median number of months to have ≥80% of influenza cases during a season in countries of the Southern hemisphere, the inter-tropical belt, and the Northern hemisphere.

<p>Median percentage of influenza cases that occurred during the 3-month peak period and median number of months to have ≥80% of influenza cases during a season in countries of the Southern hemisphere, the inter-tropical belt, and the Northern hemisphere.</p