Often Hong Kong experiences a second flu season each year - but that usually occurs in late summer - not hot on the heels of the last flu season, which appeared to be over in mid April.
But on May 4th, barely three weeks after declaring the winter epidemic ended, Hong Kong's CHP Reported A Late Season Flu Surge, and reinstated their enhanced surveillance for severe seasonal influenza.Since then we've watched the number of severe flu cases, and deaths, continue to rise (see here and here), due to a mixture of H3N2, H1N1, and influenza B viruses. While they are undoubtedly looking closely at their genetics, we've not seen anything yet to suggest there is anything unusual about these viruses.
The latest Flu Express report from Hong Kong's CHP indicates the number of flu cases continues to increase, and now Taiwan's CDC reports they are seeing a surge in influenza activity as well.First stop, Hong Kong. Then we'll look in on Taiwan.
VOLUME 14, NUMBER 20 (PUBLISHED ON May 25, 2017)
Flu Express is a weekly report produced by the Respiratory Disease Office of the Centre for Health Protection. It monitors and summarizes the latest local and global influenza activities.
Local Situation of Influenza Activity (as of May 24, 2017)
Reporting period: May 14 – 20, 2017 (Week 20)
- The latest surveillance data showed that the local influenza activity continued to increase.
- The Centre for Health Protection (CHP) has collaborated with the Hospital Authority (HA) and private hospitals to reactivate the enhanced surveillance for severe seasonal influenza cases (i.e. influenza-associated admissions to intensive care unit or deaths) among patients aged 18 or above since May 5, 2017. As of May 24, 39 severe cases (including 24 deaths) were recorded. Separately, three cases of severe paediatric influenza-associated complication/death (including one death) (aged below 18 years) were recorded in the same period.
(SNIP)(Continue . . . )
Surveillance of severe influenza cases
(Note: The data reported are provisional figures and subject to further revision)
Since the activation of the enhanced surveillance for severe influenza infection on May 5, 2017, a total of 42 severe cases (including 25 deaths) were recorded cumulatively (as of May 24) (Figure 9). These included:
- 39 cases (including 24 deaths) among adult patients aged 18 years or above. Among them, 21 patients had infection with influenza A(H3N2), 10 patients with influenza A(H1N1)pdm09, four patients with influenza B and four patients with influenza A with subtype pending. Six (15.4%) were known to have received the influenza vaccine for the 2016/17 season. Among the 24 fatal cases, six (25.0%) were known to have received the influenza vaccine. In the winter season in early 2017, 66 adult severe cases (including 41 deaths) were filed.
- Three cases (including one death) of severe paediatric influenza-associated complication/ death. All of them did not receive the influenza vaccine for the 2016/17 season. To date in 2017, 11 paediatric cases (including one death) were filed.
- Enhanced surveillance for severe seasonal influenza (Aged 18 years or above)
- In week 20, 14 cases of influenza associated ICU admission/death were recorded, in which nine of them were fatal. In the first 4 days of week 21 (May 21 to 24), eight cases of influenza associated ICU admission/death were recorded, in which six of them were fatal.
- Surveillance of severe paediatric influenza-associated complication/death (Aged below 18 years)
- In week 20, there were two cases of severe paediatric influenza-associated complication/ death. In the first 4 days of week 21 (May 21 to 24), no cases of severe paediatric influenza-associated complication/ death were reported.
While apparently not as severe, Taiwan - whose flu season seemed to have peaked two months ago - is reporting a May increase in influenza activity as well. The chart below comes from the Taiwan CDC Influenza Surveillance page, and shows the recent increase in influenza positive isolates.
The following press release comes from Taiwan's CDC:
In response to ongoing influenza activity in Taiwan, Taiwan CDC expands target population for government-funded influenza antiviral drugs from May 25 to June 30, 2017( 2017-05-25 )
In light of the increasing influenza activity in Taiwan, a slight decrease in temperatures due to recent cold fronts, the approaching Dragon Boat Festival that falls on a long weekend, and increased holiday travel, the Taiwan Centers for Disease Control (Taiwan CDC) expects outbreaks of mild influenza to persist.
To mitigate the impact of influenza outbreaks, Taiwan CDC decided to expand the target population for the government-funded influenza antiviral drug use to include family members/coworkers/classmates of confirmed influenza cases who display influenza-like illness (ILI) from May 25 to June 20, 2017. Individuals experiencing influenza symptoms may visit one of the over 3,000 contracted healthcare facilities that carry government-funded antivirals in the nation for medical treatment. Physicians are urged to heighten vigilance for patients with influenza and timely prescribe government-funded influenza antiviral drugs to eligible patients without the use of a rapid influenza diagnostic test in order to ensure prompt treatment, prevent further transmission of the disease, and reduce the occurrence of severe cases and deaths.(Continue . . . )
According to the surveillance data compiled by Taiwan CDC, during May 14 and 20, 2017, the number of people seeking ER and outpatient consultation rates for influenza-like illness was 65,116, which is 2,636 more than that the previous week (62,480). During this influenza season that began on July 1, 2016, a cumulative total of 495 complicated influenza cases, including 62 deaths, have been confirmed in Taiwan and the majority of the infections have been caused by H3N2.
It isn't clear what is behind these late season surges in flu activity in Taiwan and Hong Kong (and presumably, Mainland China), but with the Southern Hemisphere's flu season ramping up - and it sometimes being a harbinger of what the Northern Hemisphere might see in the fall - we'll be keeping a close eye on both regions.