The World Health Organization (WHO) Regional Offices and Member States, in collaboration with the Global Influenza Surveillance and Response System (GISRS), collect and submit reports on influenza activity worldwide every two weeks.
National Influenza Centers (NICs) and other national influenza laboratories from 105 countries, regions or territories report data to FluNet.
The latest report updated to October 30, 2022 contains data disaggregated by areas of influenza transmission, i.e. countries/areas with transmission patterns similar to influenza.
In addition, it covers FluNet epidemiological and viral data for the period between October 17, 2022, and October 30, 2022. During this time, WHO’s GISRS laboratories have tested more than 229,940 samples.
the main points
Influenza activity has increased globally, and the influenza virus subtype A (H3N2) has become particularly prevalent. Of the 229,940 samples tested, 15,723 tested positive for influenza viruses. The share of influenza A and influenza B viruses was 14,589 (92.8%) and 1134 (7.2%). While all described B viruses belonged to the B/Victoria strain, 1424 (21.2%) and 5284 (78.8%) of the 14,589 influenza A viruses were H1N1 and H3N2, respectively.
At the hemisphere level, while the upward trend in influenza activity continued in the Northern Hemisphere, it stabilized in the Southern Hemisphere. Based on this observation, the World Health Organization recommended countries in the northern hemisphere, including the United States and Canada, to intensify their influenza vaccination campaign to prevent hospitalizations and deaths. Most importantly, doctors should screen or test people for influenza and treat them according to national guidelines.
Despite a sharp increase in COVID-19 activity in the WHO Region of the Americas and a slight increase in Southeast Asia and the Western Pacific regions, sentinel monitoring results showed that it remained below 10% after a long-term downward trend that began in mid-2022.
Consequently, WHO has encouraged the intensification of integrated surveillance for influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in northern hemisphere harboring countries. They focused particularly on countries that have received multiple influenza and SARS-CoV-2 reagent kits from GISRS. Even the World Health Organization has published revised interim guidance for these countries that stresses the urgent need for timely reporting of epidemiological and laboratory information to its regional and global platforms.
countries of the temperate zone (Northern Hemisphere)
In countries in the temperate zone of the Northern Hemisphere, such as the United States and Canada, activity of influenza-like illness (ILI) and respiratory syncytial virus (RSV) has increased above the seasonal average for this time of year, with influenza A (H3N2) virus predominating. SARS-CoV-2 remains the causative agent behind the death rate above the epidemic level in the USA.
Influenza A (H3N2) predominated in European countries, with the highest percentage of suspected influenza cases recorded in southwestern Europe (3.62% positive). Portugal, followed by Germany and Spain, reported an increasing trend in suspected influenza activity. RSV activity has been the highest in France and is constantly increasing. Likewise, excess deaths in most age groups continued to rise in European countries. Central countries (eg, Kazakhstan) and West Asian countries, such as Saudi Arabia, have reported high/high activity of suspected influenza cases, with B strain influenza viruses prevalent in Kazakhstan. Conversely, in East Asia, influenza A (H3N2) activity remained stable at moderate levels.
countries of the temperate zone (southern hemisphere)
Overall suspected influenza case activity appears to have decreased in this reporting period, with the exception of South America, where suspected influenza case activity has increased in many countries, such as Argentina, Chile and Uruguay. In Chile and Uruguay, influenza A (H3N2) viruses predominated, while in Argentina, influenza B and influenza A (H1N1) were prevalent. Across all Pacific islands, including New Zealand, suspected influenza activity remained low except for a few countries. Similarly, in Australia, suspected influenza activity remained minimal, although influenza A (H1N1), influenza A (H3N2) and some B viruses were detected.
Tropical countries in South America and Africa had low activity of suspected influenza cases during the study period. Notably, RSV activity only increased in Brazil. In Puerto Rico, Guatemala, and parts of the Caribbean and Central America, suspected influenza activity was above average for the time of year and seasonal threshold.