Influenza Update N° 414

7 March 2022
 | Emergency situation update
Influenza Update N° 414
Download (1.1 MB)

Overview

7 March 2022, based on data up to 20 February 2022

Information in this report is categorized by influenza transmission zones, which are geographical groups of countries, areas or territories with similar influenza transmission patterns. For more information on influenza transmission zones, see the link below:

Influenza Transmission Zones (pdf, 659kb)

  • The current influenza surveillance data should be interpreted with caution as the ongoing COVID-19 pandemic has influenced to varying extents health seeking behaviours, staffing/routines in sentinel sites, as well as testing priorities and capacities in Member States. Various hygiene and physical distancing measures implemented by Member States to reduce SARS-CoV-2 virus transmission have likely played a role in reducing influenza virus transmission. 
  • Globally, influenza activity remained low and decreased this period after a peak at the end of 2021.
  • With the increasing detections of influenza during COVID-19 pandemic, countries are recommended to prepare for co-circulation of influenza and SARS-CoV-2 viruses. They are encouraged to enhance integrated surveillance to monitor influenza and SARS-CoV-2 at the same time, and step-up their influenza vaccination campaign to prevent severe disease and hospitalizations associated with influenza. Clinicians should consider influenza in differential diagnosis especially for high-risk groups for influenza, and test and treat according to national guidance.
  • In the temperate zones of the northern hemisphere, influenza activity decreased with detections of mainly influenza A(H3N2) viruses and B/Victoria lineage viruses reported.
  • In North America, influenza virus detections remained low and were predominantly A(H3N2) among those detected and subtyped. Respiratory syncytial virus (RSV) activity also further decreased in the USA and Canada. 
  • In Europe, influenza activity remained stable at low levels with influenza A(H3N2) predominant. Very little RSV activity was observed.
  • In East Asia, influenza activity with mainly influenza B/Victoria lineage detections decreased in China. Influenza illness indicators and activity remained low in the rest of the subregion. 
  • In Northern Africa, influenza detections of influenza A(H3N2) continued to be reported. 
  • In Western Asia, influenza activity was low across reporting countries.
  • In the Caribbean and Central American countries, influenza activity of predominantly influenza A(H3N2) decreased overall.
  • In tropical South America, low influenza activity was reported with influenza A(H3N2) predominant.
  • In tropical Africa, influenza activity was reported mainly from Eastern Africa with influenza A(H3N2) predominating followed by influenza B/Victoria lineage, and from Middle Africa with influenza B predominantly detected.
  • In Southern Asia, influenza virus detections of predominantly influenza A(H3N2) decreased.
  • In South-East Asia, mainly influenza A(H3N2) detections were reported as well as some influenza B. RSV activity was elevated in Mongolia and Republic of Korea.
  • At the global level, SARS-CoV-2 percent positivity from sentinel surveillance decreased across all WHO regions during this reporting period. However, positivity rate was above 50% in the Eastern Mediterranean and between 20% and 30% in all other Regions of WHO, with exception of the African Region of WHO where positivity remained under 10%. Overall positivity from non-sentinel sites also showed a decreasing trend.
  • In the temperate zones of the southern hemisphere, influenza activity remained low overall, although increased detections of influenza A(H3N2) were reported in some countries in temperate South America.
  • National Influenza Centres (NICs) and other national influenza laboratories from 115 countries, areas or territories reported data to FluNet for the time period from 07 February 2022 to 20 February 2022* (data as of 2022-03-04 08:07:21 UTC). The WHO GISRS laboratories tested more than 419 390 specimens during that time period. A total of 13 619 specimens were positive for influenza viruses, of which 9 346 (68.6%) were typed as influenza A and 4 273 (31.4%) as influenza B. Of the subtyped influenza A viruses, 224 (11.1%) were influenza A(H1N1)pdm09 and 1 797 (88.9%) were influenza A(H3N2). Of the type B viruses for which lineage was determined, 4 085 (100%) belonged to the B-Victoria lineage.

 

 

During the COVID-19 pandemic, WHO encourages countries, especially those that have received the multiplex influenza and SARS-CoV-2 reagent kits from GISRS, to conduct integrated surveillance of influenza and SARS-CoV-2 and report epidemiological and laboratory information in a timely manner to established regional and global platforms. Revised interim guidance has just been published here: https://covid.comesa.int/publications/i/item/WHO-2019-nCoV-integrated_sentinel_surveillance-2022.1.

  • At the global level, SARS-CoV-2 percent positivity from sentinel surveillance decreased across all WHO regions during this reporting period. However, positivity rate was above 50% in the Eastern Mediterranean and between 20% and 30% in all other Regions of WHO, with exception of the African Region of WHO where positivity remained under 10%. Overall positivity from non-sentinel sites also showed a decreasing trend.
  • NICs and other national influenza laboratories from 57 countries, areas or territories from six WHO regions (African Region: 1; Region of the Americas: 16; Eastern Mediterranean Region: 3; European Region: 28; South-East Asia Region: 4; Western Pacific Region: 5) reported to FluNet from sentinel surveillance sites for time period from 07 Feb 2022 to 20 Feb 2022 (data as of 2022-03-04 08:07:21 UTC). The WHO GISRS laboratories tested more than 88 036 sentinel specimens during that time period and 29 789 (33.8%) were positive for SARS-CoV-2. Additionally, more than 2.3 million non-sentinel or undefined reporting source samples were tested in the same period and 694 820 were positive for SARS-CoV-2. Further details are included at the end of this update.

 

Source of data

______________________________________________________________________________________________

The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks. The updates are based on available epidemiological and virological data sources, including FluNet (reported by the WHO Global Influenza Surveillance and Response System), FluID (epidemiological data reported by national focal points) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.

*It includes data only from countries reporting on positive and negative influenza specimens.

 

WHO Team
Global Influenza Programme (GIP)