Hong Kong Reports A Decrease In Their Late Season Flu Surge

#12,544

Five weeks into Hong Kong's unusual late season flu surge (see first report CHP Reported A Late Season Flu Surge), in week 23 a small decrease in activity has been detected, although the number of severe cases remains elevated.

So far, at least 98 severe cases (including 67 deaths) have been reported since May 5th, including 10 severe pediatric cases (2 of which were fatal).

The viruses responsible have been a mixture of seasonal influenza A (H3N2 & H1N1), influenza B, and influenza C. The incidence reported in this latest report are 79.2% (H3N2), 14.1% (H1N1), 5.1% (B) and 1.6% (C).

Although the timing and severity of these cases is a bit unusual, we've seen nothing to suggest anything unusual about the viruses circulating in Hong Kong.

Despite the this week's slowdown, 21 new severe cases (including 2 pediatric) and 17 deaths have been added since last week's report.

This from today's Hong Kong's Flu Express.

VOLUME 14, NUMBER 23 (PUBLISHED ON Jun 15, 2017)
FLU EXPRESS

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 Jun 14, 2017)
Reporting period: Jun 4 – 10, 2017 (Week 23)

• The latest surveillance data showed that the local influenza activity has decreased when compared with the previous week, but it still remained at an elevated level.
• 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 Jun 14, 88 severe cases (including 65 deaths) were recorded. Separately, ten cases of severe paediatric influenza-associated complication/death (including two deaths) (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.

 (SNIP)

        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 98 severe cases (including 67 deaths) were recorded cumulatively (as of Jun 14) (Figure 9). These included:

• 88 cases (including 65 deaths) among adult patients aged 18 years or above. Among them, 64 patients had infection with influenza A(H3N2), 14 patients with influenza A(H1N1)pdm09, six patients with influenza B and four patients with influenza A pending subtype. Thirty (34.1%) were known to have received the influenza vaccine for the 2016/17 season. Among the 65 fatal cases, 28 (43.1%) were known to have received the influenza vaccine. In the winter season in early 2017, 66 adult severe cases (including 41 deaths) were filed.
• Ten cases (including two deaths) of severe paediatric influenza-associated complication/ death. Nine (90.0%) cases did not receive the influenza vaccine for the 2016/17 season. To date in 2017, 18 paediatric cases (including three deaths) were filed.

Enhanced surveillance for severe seasonal influenza (Aged 18 years or above)

• In week 23, 17 cases of influenza associated ICU admission/death were recorded, in which 15 of them were fatal. In the first 4 days of week 24 (Jun 11 to 14), ten cases of influenza associated ICU admission/death were recorded, in which eight of them were fatal.

Surveillance of severe paediatric influenza-associated complication/death (Aged below 18 years)

•  In week 23, there was one case of severe paediatric influenza-associated complication. In the first 4 days of week 24 (Jun 11 to 14), one case of severe paediatric influenza-associated complication was reported.

          (Continue . . . )


We'll need another week or two of reporting to know if this week's decrease is an artifact, or a trend.

Meanwhile, with flu activity beginning to ramp up in Australia, southern South America, and South Africa we'll be keeping a keen eye to see if they report similar increased flu severity.