|HK Flu Express - Week 19|
Hong Kong is well known for its unique biphasic or `double peaked’ flu season, with their heaviest activity usually from February–April and (a less severe) season in June through August (see Seasonality of Influenza A(H3N2) Virus: A Hong Kong Perspective (1997–2006).
A little over a month ago, Hong Kong's CHP declared the end of this winter's flu epidemic with their Flu Express Week 15 reporting a `low level' of flu activity.
Two weeks ago, quite unexpectedly, the Hong Kong CHP Reported A Late Season Flu Surge, and reinstated their enhanced surveillance for severe seasonal influenza.
Last week, in Follow Up On Hong Kong's Flu Resurgence, the Flu Express (week 18) indicated there were 14 flu-related ICU admissions and 6 deaths. Of those 14 severe cases, half were identified as H3N2, 3 were H1N1, one was Influenza B, and 3 are influenza A with subtype pending.
Today, Hong Kong releases the second Flu Express of this new flu wave (week 19), and we learn that the number of severe flu cases continues to rise, with 30 severe cases (and 14 deaths) over the past 12 days.
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 17, 2017)
Reporting period: May 7 – May 13, 2017 (Week 19)
- The latest surveillance data showed that the local influenza activity has further increased in the past week, signaling that Hong Kong has entered the influenza season.
- 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 17, 27 severe cases (including 14 deaths) were recorded. Separately, three cases of severe paediatric influenza-associated complications (aged below 18 years) were recorded in the same period.
- Apart from adopting personal, hand and environmental hygiene practices against respiratory illnesses, those members of the public who have not received influenza vaccine are urged to get vaccinated as soon as possible for personal protection.
- Influenza can cause serious illnesses in high-risk individuals and even healthy persons. Given that seasonal influenza vaccines are safe and effective, all persons aged 6 months or above except those with known contraindications are recommended to receive influenza vaccine for personal protection.
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 30 severe cases (including 14 deaths) were recorded cumulatively (as of May 17) (Figure 9). These included:
- 27 cases (including 14 deaths) among adult patients aged 18 years or above. Among them, 15 patients had infection with influenza A(H3N2), eight patients with influenza A(H1N1)pdm09, three patients with influenza B and one patient with influenza A without subtype. Three (11.1%) were known to have received the influenza vaccine for the 2016/17 season. Among the 14 fatal cases, two (14.3%) 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 of severe paediatric influenza-associated complication. 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 19, 11 cases of influenza associated ICU admission/death were recorded, in which five of them were fatal. In the first 4 days of week 20 (May 14 to 17), ten cases of influenza associated ICU admission/death were recorded, in which five of them were fatal.
- Surveillance of severe paediatric influenza-associated complication/death (Aged below 18 years)
- In week 19, one case of severe paediatric influenza-associated complication was reported. In the first 4 days of week 20 (May 14 to 17), there were two cases of severe paediatric influenza-associated complication. The case details are as follow:
(Continue . . . )
While more unusual than alarming at this point, this illustrates just how unpredictable influenza can be.
As an international city - one that receives tens of thousands of visitors each day from the Mainland and from around the world - Hong Kong's flu surveillance is uniquely positioned to serve as an early warning system for both seasonal and novel flu.So far, we've not seen any indication of changes to these viruses. But between the experts at the University of Hong Kong and the CHP, I'm confident we'll quickly hear if there's anything new or unusual about these recent flu cases.