On 24 January 2021, two new cases of human infection with avian influenza A(H5N6) virus were reported to WHO in the Western Pacific Region. The first case is a three-year-old female from Guizhou Province, China who was admitted to hospital with severe illness and died on 22 December 2020. The second case is a one-year-old female from Anhui Province, China who developed mild illness in December 2020. Both cases were sporadic and had exposure to poultry at markets prior to onset of illness. To date, a total of 29 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including nine deaths have been reported to WHO from China since 2014.
The most recent risk assessment on HPAI H5 viruses from the WHO reads:
Public health risk assessment for human infection with avian influenza A(H5) viruses
Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, sporadic human cases are not unexpected. With continued incidence of avian influenza due to existing and new influenza A(H5) viruses in poultry, there is a need to remain vigilant in the animal and public health sectors. Community awareness of the potential dangers for human health is essential to prevent infection in humans. Surveillance should be continued to detect human cases and early changes in transmissibility and infectivity of the viruses.
For more information on confirmed cases of human infection with avian influenza A(H5) virus reported to WHO, visit: http://www.who.int/influenza/human_animal_interface/en/ For information on monthly risk assessments on Avian Influenza, visit: http://www.who.int/influenza/human_animal_interface/HAI_Risk_Assessment/en/
Up until the middle of 2017 China was a hotbed of both H5 and H7 avian flu viruses, and had been reporting literally hundreds of human infections (mostly H7) each year for nearly a half a decade. H7N9 was, by far, the most worrisome of the viruses, but HPAI H5N6 was growing in stature as well.
EID Journal: Genetic Characterization of Avian Influenza A(H5N6) Virus Clade 2.3.4.4, Russia, 2018
EID Journal: HPAI H5N6 In Domestic Cats - Korea, 2016
J. Infect.: Pathogenicity & Transmissibility of 3 Avian H5N6 Viruses Isolated From Wild Birds
In the summer of 2017, in the wake of a disastrous spring surge in H7N9 infections and the emergence of an HPAI strain, China's MOA announced plans to test a new experimental H5+H7 poultry vaccine in two provinces (Guangdong & Guangxi).
With mounting fears that H7N9 was creeping ever closer to becoming a pandemic strain, less than a month later the MOA Ordered HPAI H7N9 Vaccine Deployed Nationwide by the fall.
The H7N9 epidemic in poultry and in humans was quickly halted, and over the next three years, only a handful of human H5N6 cases have been reported. HPAI H5 outbreaks in poultry, while not completely eliminated, have also been greatly reduced.
Whether simply coincidental or connected to China's vaccination campaign, globally HPAI H5 went into a steep decline in 2017 as well, only starting to show signs of renewed life about a year ago.
Last fall, HPAI H5N8 began its biggest run since the winter of 2016-2017 in Europe (see DEFRA Report Updated Outbreak Assessment #14 Highly pathogenic avian influenza (HPAI) in the UK,and Europe 02 February 2021).
Today's HK Avian Flu Report (Vol 17, No 6) lists 21 countries, from Asia to Europe to Africa reporting outbreaks of HPAI H5 in poultry and/or wild birds over the past week. Given delays and spotting surveillance, this is also likely an under-representation of AI's impact.
As we try to cope with the COVID-19 pandemic, avian flu has returned worldwide with a vengeance. Most of these outbreaks are due to H5N8, which has not been shown to infect humans (yet), but we are also seeing H5N6 and H5N1 increasing around the globe.
Surveillance and reporting is less than optimal even when we aren't in a pandemic, but is undoubtedly even less robust today. In too many ways, we are still Flying Blind In the Age Of Pandemics & Emerging Infectious Diseases.
