Spatio-temporal patterns of influenza B proportions

TL;DR

This study analyzes the global spatio-temporal patterns of influenza B proportions using data from 139 countries, revealing correlations with effective distance from Mexico and pandemic impacts on influenza type distribution.

Contribution

It provides a comprehensive analysis of influenza B proportions across multiple countries over a decade, highlighting the pandemic's influence on influenza dynamics.

Findings

Pearson's correlation of 0.669 between effective distance from Mexico and influenza B proportion.

Negative correlation of influenza B proportion between pre- and post-pandemic periods in the US.

Wide variations in influenza B proportions over the study period.

Abstract

We study the spatio-temporal patterns of the proportion of influenza B out of laboratory confirmations of both influenza A and B, with data from 139 countries and regions downloaded from the FluNet compiled by the World Health Organization, from January 2006 to October 2015, excluding 2009. We restricted our analysis to 34 countries that reported more than 2000 confirmations for each of types A and B over the study period. We find that Pearson's correlation is 0.669 between effective distance from Mexico and influenza B proportion among the countries from January 2006 to October 2015. In the United States, influenza B proportion in the pre-pandemic period (2003-2008) negatively correlated with that in the post-pandemic era (2010-2015) at the regional level. Our study limitations are the country-level variations in both surveillance methods and testing policies. Influenza B proportion displayed wide variations over the study period. Our findings suggest that even after excluding 2009's data, the influenza pandemic still has an evident impact on the relative burden of the two influenza types. Future studies could examine whether there are other additional factors. This study has potential implications in prioritizing public health control measures.