Hong Kong CHP: 7 Recent H9N2 Cases Reported From the Mainland
#18,410
Over the past 6 months reporting of novel flu cases from Mainland China has dropped appreciably, with
the last H5N6 case reported in July, and
only 4 H9N2 cases reported between May and the end of October (see chart below).
Of course, a lack of reports doesn't always mean a lack of cases, since
China often only belatedly reports novel flu cases. Sometimes this is because of delays in testing, and sometimes because it its politically expedient.
Today, Hong Kong's CHP has published a bare bones listing of
7 newly announced H9N2 cases, all of which occurred in
just 3 weeks in Mainland China.
While LPAI H9N2 is admittedly not at the very top of our list of pandemic concerns, the CDC has 2 different lineages (
A(H9N2) G1 and
A(H9N2) Y280) on their short list of influenza viruses with zoonotic potential (see
CDC IRAT SCORE), and
several candidate vaccines have been developed.
Only about
140 cases have been officially reported over the past 20 years (see
FluTrackers list), and most
(but not all) of them have reported
mild or moderate illness.
Seroprevalence studies, however, suggest the infection is far more common than we believe.
H9N2 is poorly controlled in Chinese poultry, despite the use of vaccines (see
J. Virus Erad.: Ineffective Control Of LPAI H9N2 By Inactivated Poultry Vaccines - China), which has led to the creation and spread of numerous of genotypes.
Details are scant, and the significant of today's announcement is difficult to determine. It
could be due to increased surveillance, or it
might signify an increase in transmission.
We'll obviously be watching China closely for future reports.
Some earlier (2024) blogs on HPAI H9N2 include:
https://afludiary.blogspot.com/2024/11/hong-kong-chp-7-recent-h9n2-cases.html
